RÉSUMÉ
HNRNPA1 variants are known to cause degenerative motoneuron and muscle diseases which manifests in middle age or later. We report on a girl with early childhood onset, rapidly progressive generalized myopathy including ultrastructural findings in line with a proteinopathy. Proteomics of patient-derived muscle and combined screening of genomic data for copy number variations identified a HNRNPA1 de novo intragenic deletion as causative for the phenotype. Our report expands the spectrum of HNRNPA1-related diseases towards early-childhood onset and adds HNRNPA1 to the growing list of ALS and myopathy genes for which certain mutations may cause severe pediatric phenotypes.
RÉSUMÉ
PURPOSE: Cancer is a life threatening disease with negative impact on quality of life and psychological well-being. In international studies, one-to-one peer support and counseling have been shown to improve the psychological well-being of cancer patients. In the study presented, we developed and evaluated an innovative program of peer-coaching. In this program at the University Hospital of Freiburg, cancer survivors were trained to support peers by sharing experience. METHODS: In the project, N = 25 cancer survivors were trained to conduct supportive one-to-one conversations with acute patients or patients in aftercare. Based on a prospective observational study, patients were interviewed using questionnaires before and after the conversations. We assessed expectations and experiences with the peer-coaching as well as psychosocial parameters (PHQ9, GAD7, SSUK, NCCN-distress thermometer). RESULTS: A total of 52 patients had at least one contact with a peer-coach. Most of the patients attended 1-3 sessions. In total, 85 contacts pairing peer-coaches with patients were conducted. Patients showed on average a high level of distress but a low rate of psychiatric comorbidity. The supportive conversations met the patients` needs. Sharing experiences and empowerment were the most relevant benefits for the patients. Both patients and trained peers showed high satisfaction levels with the program. CONCLUSION: Our findings support the feasibility and utility of a peer-coaching program in which trained cancer survivors, acting as peer-coaches, support other patients during or after their oncological treatment. In a further study, the efficacy of peer-coaching should be investigated based on a randomized-controlled trial. TRIAL REGISTRATION: The trial was registered in the German Clinical Trials Register (No. DRKS DRKS00017500) on 12.12.2019.
Sujet(s)
Tumeurs , Groupe de pairs , Humains , Projets pilotes , Femelle , Mâle , Adulte d'âge moyen , Tumeurs/psychologie , Tumeurs/thérapie , Sujet âgé , Études prospectives , Adulte , Survivants du cancer/psychologie , Qualité de vie , Mentorat/méthodes , Soutien social , Assistance/méthodes , Enquêtes et questionnairesRÉSUMÉ
Medulloblastomas (MBs) are malignant pediatric brain tumors that are molecularly and clinically heterogenous. The application of omics technologies-mainly studying nucleic acids-has significantly improved MB classification and stratification, but treatment options are still unsatisfactory. The proteome and their N-glycans hold the potential to discover clinically relevant phenotypes and targetable pathways. We compile a harmonized proteome dataset of 167 MBs and integrate findings with DNA methylome, transcriptome and N-glycome data. We show six proteome MB subtypes, that can be assigned to two main molecular programs: transcription/translation (pSHHt, pWNT and pG3myc), and synapses/immunological processes (pSHHs, pG3 and pG4). Multiomic analysis reveals different conservation levels of proteome features across MB subtypes at the DNA methylome level. Aggressive pGroup3myc MBs and favorable pWNT MBs are most similar in cluster hierarchies concerning overall proteome patterns but show different protein abundances of the vincristine resistance-associated multiprotein complex TriC/CCT and of N-glycan turnover-associated factors. The N-glycome reflects proteome subtypes and complex-bisecting N-glycans characterize pGroup3myc tumors. Our results shed light on targetable alterations in MB and set a foundation for potential immunotherapies targeting glycan structures.
Sujet(s)
Médulloblastome , Polyosides , Protéome , Médulloblastome/métabolisme , Médulloblastome/génétique , Humains , Polyosides/métabolisme , Protéome/métabolisme , Tumeurs du cervelet/métabolisme , Tumeurs du cervelet/génétique , Méthylation de l'ADN , Transcriptome , Enfant , Protéomique/méthodes , Femelle , Régulation de l'expression des gènes tumoraux , Mâle , Enfant d'âge préscolaire , Analyse de profil d'expression de gènes/méthodesRÉSUMÉ
Myositis with anti-Ku-autoantibodies is a rare inflammatory myopathy associated with various connective tissue diseases. Histopathological studies have identified inflammatory and necrotizing aspects, but a precise morphological analysis and pathomechanistic disease model are lacking. We therefore aimed to carry out an in-depth morpho-molecular analysis to uncover possible pathomechanisms. Muscle biopsy specimens from 26 patients with anti-Ku-antibodies and unequivocal myositis were analyzed by immunohistochemistry, immunofluorescence, transcriptomics, and proteomics and compared to biopsy specimens of non-disease controls, immune-mediated necrotizing myopathy (IMNM), and inclusion body myositis (IBM). Clinical findings and laboratory parameters were evaluated retrospectively and correlated with morphological and molecular features. Patients were mainly female (92%) with a median age of 56.5 years. Isolated myositis and overlap with systemic sclerosis were reported in 31%, respectively. Isolated myositis presented with higher creatine kinase levels and cardiac involvement (83%), whereas systemic sclerosis-overlap patients often had interstitial lung disease (57%). Histopathology showed a wide spectrum from mild to pronounced myositis with diffuse sarcolemmal MHC-class I (100%) and -II (69%) immunoreactivity, myofiber necrosis (88%), endomysial inflammation (85%), thickened capillaries (84%), and vacuoles (60%). Conspicuous sarcoplasmic protein aggregates were p62, BAG3, myotilin, or immunoproteasomal beta5i-positive. Proteomic and transcriptomic analysis identified prominent up-regulation of autophagy, proteasome, and hnRNP-related cell stress. To conclude, Ku + myositis is morphologically characterized by myofiber necrosis, MHC-class I and II positivity, variable endomysial inflammation, and distinct protein aggregation varying from IBM and IMNM, and it can be placed in the spectrum of scleromyositis and overlap myositis. It features characteristic sarcoplasmic protein aggregation on an acquired basis being functionally associated with altered chaperone, proteasome, and autophagy function indicating that Ku + myositis exhibit aspects of an acquired inflammatory protein-aggregate myopathy.
Sujet(s)
Autoanticorps , Autoantigène Ku , Myosite , Humains , Femelle , Adulte d'âge moyen , Mâle , Myosite/anatomopathologie , Myosite/immunologie , Myosite/métabolisme , Sujet âgé , Autoanticorps/immunologie , Adulte , Autoantigène Ku/métabolisme , Muscles squelettiques/anatomopathologie , Muscles squelettiques/métabolisme , Études rétrospectives , Myosite à inclusions/anatomopathologie , Myosite à inclusions/métabolismeRÉSUMÉ
Patient-reported outcomes (PROs) offer a diverse array of potential applications within medical research and clinical practice. In comparative research, they can serve as tools for delineating the trajectories of health-related quality of life (HRQoL) across various cancer types. We undertook a secondary data analysis of a cohort of 1498 hospitalized cancer patients from 13 German cancer centers. We assessed the Physical and Mental Component Scores (PCS and MCS) of the 12-Item Short-Form Health Survey at baseline (t0), 6 (t1), and 12 months (t2), using multivariable generalized linear regression models. At baseline, the mean PCS and MCS values for all cancer patients were 37.1 and 44.3 points, respectively. We observed a significant improvement in PCS at t2 and in MCS at t1. The most substantial and significant improvements were noted among patients with gynecological cancers. We found a number of significant differences between cancer types at baseline, t1, and t2, with skin cancer patients performing best across all time points and lung cancer patients performing the worst. MCS trajectories showed less pronounced changes and differences between cancer types. Comparative analyses of HRQoL scores across different cancer types may serve as a valuable tool for enhancing health literacy, both among the general public and among cancer patients themselves.
Sujet(s)
Hospitalisation , Tumeurs , Qualité de vie , Humains , Femelle , Mâle , Allemagne , Adulte d'âge moyen , Tumeurs/psychologie , Hospitalisation/statistiques et données numériques , Sujet âgé , Mesures des résultats rapportés par les patients , Adulte , Analyse de données , Établissements de cancérologie , Analyses secondaires des donnéesRÉSUMÉ
Background: NEFL encodes for the neurofilament light chain protein. Pathogenic variants in NEFL cause demyelinating, axonal and intermediate forms of Charcot-Marie-Tooth disease (CMT) which present with a varying degree of severity and somatic mutations have not been described yet. Currently, 34 different CMT-causing pathogenic variants in NEFL in 174 patients have been reported. Muscular involvement was also described in CMT2E patients mostly as a secondary effect. Also, there are a few descriptions of a primary muscle vulnerability upon pathogenic NEFL variants. Objectives: To expand the current knowledge on the genetic landscape, clinical presentation and muscle involvement in NEFL-related neurological diseases by retrospective case study and literature review. Methods: We applied in-depth phenotyping of new and already reported cases, molecular genetic testing, light-, electron- and Coherent Anti-Stokes Raman Scattering-microscopic studies and proteomic profiling in addition to in silico modelling of NEFL-variants. Results: We report on a boy with a muscular phenotype (weakness, myalgia and cramps, Z-band alterations and mini-cores in some myofibers) associated with the heterozygous p.(Phe104Val) NEFL-variant, which was previously described in a neuropathy case. Skeletal muscle proteomics findings indicated affection of cytoskeletal proteins. Moreover, we report on two further neuropathic patients (16 years old girl and her father) both carrying the heterozygous p.(Pro8Ser) variant, which has been identified as 15% somatic mosaic in the father. While the daughter presented with altered neurophysiology,neurogenic clump feet and gait disturbances, the father showed clinically only feet deformities. As missense variants affecting proline at amino acid position 8 are leading to neuropathic manifestations of different severities, in silico modelling of these different amino acid substitutions indicated variable pathogenic impact correlating with disease onset. Conclusions: Our findings provide new morphological and biochemical insights into the vulnerability of denervated muscle (upon NEFL-associated neuropathy) as well as novel genetic findings expanding the current knowledge on NEFL-related neuromuscular phenotypes and their clinical manifestations. Along this line, our data show that even subtle expression of somatic NEFL variants can lead to neuromuscular symptoms.
Sujet(s)
Maladie de Charcot-Marie-Tooth , Protéines neurofilamenteuses , Phénotype , Humains , Mâle , Protéines neurofilamenteuses/génétique , Maladie de Charcot-Marie-Tooth/génétique , Muscles squelettiques/anatomopathologie , Muscles squelettiques/métabolisme , Études rétrospectives , Enfant , Adolescent , Femelle , MutationSujet(s)
Maladies musculaires , Humains , Mâle , Femelle , Enfant , Maladies musculaires/génétique , Mutation , Âge de début , PedigreeRÉSUMÉ
Myelin protein zero (MPZ/P0) is a major structural protein of peripheral nerve myelin. Disease-associated variants in the MPZ gene cause a wide phenotypic spectrum of inherited peripheral neuropathies. Previous nerve biopsy studies showed evidence for subtype-specific morphological features. Here, we aimed at enhancing the understanding of these subtype-specific features and pathophysiological aspects of MPZ neuropathies. We examined archival material from two Central European centers and systematically determined genetic, clinical, and neuropathological features of 21 patients with MPZ mutations compared to 16 controls. Cases were grouped based on nerve conduction data into congenital hypomyelinating neuropathy (CHN; n = 2), demyelinating Charcot-Marie-Tooth (CMT type 1; n = 11), intermediate (CMTi; n = 3), and axonal CMT (type 2; n = 5). Six cases had combined muscle and nerve biopsies and one underwent autopsy. We detected four MPZ gene variants not previously described in patients with neuropathy. Light and electron microscopy of nerve biopsies confirmed fewer myelinated fibers, more onion bulbs and reduced regeneration in demyelinating CMT1 compared to CMT2/CMTi. In addition, we observed significantly more denervated Schwann cells, more collagen pockets, fewer unmyelinated axons per Schwann cell unit and a higher density of Schwann cell nuclei in CMT1 compared to CMT2/CMTi. CHN was characterized by basal lamina onion bulb formation, a further increase in Schwann cell density and hypomyelination. Most late onset axonal neuropathy patients showed microangiopathy. In the autopsy case, we observed prominent neuromatous hyperinnervation of the spinal meninges. In four of the six muscle biopsies, we found marked structural mitochondrial abnormalities. These results show that MPZ alterations not only affect myelinated nerve fibers, leading to either primarily demyelinating or axonal changes, but also affect non-myelinated nerve fibers. The autopsy case offers insight into spinal nerve root pathology in MPZ neuropathy. Finally, our data suggest a peculiar association of MPZ mutations with mitochondrial alterations in muscle.
Sujet(s)
Maladie de Charcot-Marie-Tooth , Protéine P0 de la myéline , Humains , Protéine P0 de la myéline/génétique , Maladie de Charcot-Marie-Tooth/génétique , Maladie de Charcot-Marie-Tooth/anatomopathologie , Mutation/génétique , Protéines/génétique , BiopsieRÉSUMÉ
PURPOSE: Patients with cancer suffer from a wide range of psychological distress. Nevertheless, in the literature low utilization rates of psychooncological services are reported. Various factors may influence the utilization of professional support during inpatient care. Up to now it is unclear to what extent patients' attitude towards psychooncological support and physicians' recommendation for psychooncological care may influence the utilization. METHODS: In a multicenter longitudinal observational study in Comprehensive Cancer Centers Germany, 1398 patients with mixed cancer diagnoses were assessed at baseline during their hospital stay with respect to psychooncological distress and the need for and use of psychooncological services. RESULTS: Psychooncological support was used by almost 28.4% of patients up to this time. A positive attitude towards psychooncological support was reported by 41.6%. A recommendation of psychooncological support by a physician was received by 16.2%. These patients reported a significant higher level of distress compared to patients who did not received a recommendation. Multivariable logistic regression detected that the utilization rate was 3.79 times higher among patients with positive attitude towards psychooncological support (OR, 3.79; 95% CI 2.51-5.73, p < 0.001). Utilization was 4.21 times more likely among patients who received a physician´s recommendation (OR, 4.21; 95% CI 2.98-5.95, p < 0.001). CONCLUSION: The results of the study provide evidence of the relevance of giving more attention to psychooncological distress and attitudes towards psychooncological care. To reduce reservations, patients need low-threshold information about the psychooncological services offered.
Sujet(s)
Tumeurs , Médecins , Humains , Anxiété , Acceptation des soins par les patients/psychologie , Patients , Tumeurs/thérapie , Tumeurs/psychologieRÉSUMÉ
BACKGROUND: Older primary central nervous system lymphoma (PCNSL) patients have an inferior prognosis compared to younger patients because available evidence on best treatment is scarce and treatment delivery is challenging due to comorbidities and reduced performance status. High-dose chemotherapy and autologous stem cell transplantation (HCT-ASCT) after high-dose methotrexate (MTX)-based immuno-chemotherapy has become an increasingly used treatment approach in eligible elderly PCNSL patients with promising feasibility and efficacy, but has not been compared with conventional chemotherapy approaches. In addition, eligibility for HCT-ASCT in elderly PCNSL is not well defined. Geriatric assessment (GA) may be helpful in selecting patients for the best individual treatment choice, but no standardized GA exists to date. A randomized controlled trial, incorporating a GA and comparing age-adapted HCT-ASCT treatment with conventional chemotherapy is needed. METHODS: This open-label, multicenter, randomized phase III trial with two parallel arms will recruit 310 patients with newly diagnosed PCNSL > 65 years of age in 40 centers in Germany and Austria. The primary objective is to demonstrate that intensified chemotherapy followed by consolidating HCT-ASCT is superior to conventional chemotherapy with rituximab, MTX, procarbazine (R-MP) followed by maintenance with procarbazine in terms of progression free survival (PFS). Secondary endpoints include overall survival (OS), event free survival (EFS), (neuro-)toxicity and quality of life (QoL). GA will be conducted at specific time points during the course of the study. All patients will be treated with a pre-phase rituximab-MTX (R-MTX) cycle followed by re-assessment of transplant eligibility. Patients judged transplant eligible will be randomized (1:1). Patients in arm A will be treated with 3 cycles of R-MP followed by maintenance therapy with procarbazine for 6 months. Patients in arm B will be treated with 2 cycles of MARTA (R-MTX/AraC) followed by busulfan- and thiotepa-based HCT-ASCT. DISCUSSION: The best treatment strategy for elderly PCNSL patients remains unknown. Treatments range from palliative to curative but more toxic therapies, and there is no standardized measure to select patients for the right treatment. This randomized controlled trial will create evidence for the best treatment strategy with the focus on developing a standardized GA to help define eligibility for an intensive treatment approach. TRIAL REGISTRATION: German clinical trials registry DRKS00024085 registered March 29, 2023.
Sujet(s)
Transplantation de cellules souches hématopoïétiques , Lymphomes , Sujet âgé , Humains , Qualité de vie , Procarbazine , Rituximab , Transplantation autologue , Lymphomes/traitement médicamenteuxRÉSUMÉ
Summary The S3-guideline on endometrial cancer, first published in April 2018, was reviewed in its entirety between April 2020 and January 2022 and updated. The review was carried out at the request of German Cancer Aid as part of the Oncology Guidelines Program and the lead coordinators were the German Society for Gynecology and Obstetrics (DGGG), the Gynecology Oncology Working Group (AGO) of the German Cancer Society (DKG) and the German Cancer Aid (DKH). The guideline update was based on a systematic search and assessment of the literature published between 2016 and 2020. All statements, recommendations and background texts were reviewed and either confirmed or amended. New statements and recommendations were included where necessary. Aim The use of evidence-based risk-adapted therapies to treat women with endometrial cancer of low risk prevents unnecessarily radical surgery and avoids non-beneficial adjuvant radiation therapy and/or chemotherapy. For women with endometrial cancer and a high risk of recurrence, the guideline defines the optimum level of radical surgery and indicates whether chemotherapy and/or adjuvant radiation therapy is necessary. This should improve the survival rates and quality of life of these patients. The S3-guideline on endometrial cancer and the quality indicators based on the guideline aim to provide the basis for the work of certified gynecological cancer centers. Methods The guideline was first compiled in 2018 in accordance with the requirements for S3-level guidelines and was updated in 2022. The update included an adaptation of the source guidelines identified using the German Instrument for Methodological Guideline Appraisal (DELBI). The update also used evidence reviews which were created based on selected literature obtained from systematic searches in selected literature databases using the PICO process. The Clinical Guidelines Service Group was tasked with carrying out a systematic search and assessment of the literature. Their results were used by interdisciplinary working groups as a basis for developing suggestions for recommendations and statements which were then modified during structured online consensus conferences and/or additionally amended online using the DELPHI process to achieve a consensus. Recommendations Part 1 of this short version of the guideline provides recommendations on epidemiology, screening, diagnosis, and hereditary factors. The epidemiology of endometrial cancer and the risk factors for developing endometrial cancer are presented. The options for screening and the methods used to diagnose endometrial cancer are outlined. Recommendations are given for the prevention, diagnosis, and therapy of hereditary forms of endometrial cancer. The use of geriatric assessment is considered and existing structures of care are presented.
RÉSUMÉ
Schwann cell (SC) transplantation represents a promising therapeutic approach for traumatic spinal cord injury but is frustrated by barrier formation, preventing cell migration, and axonal regeneration at the interface between grafted SCs and reactive resident astrocytes (ACs). Although regenerating axons successfully extend into SC grafts, only a few cross the SC-AC interface to re-enter lesioned neuropil. To date, research has focused on identifying and modifying the molecular mechanisms underlying such scarring cell-cell interactions, while the influence of substrate topography remains largely unexplored. Using a recently modified cell confrontation assay to model SC-AC barrier formation in vitro, highly oriented poly(ε-caprolactone) nanofibers were observed to reduce AC reactivity, induce extensive oriented intermingling between SCs and ACs, and ultimately enable substantial neurite outgrowth from the SC compartment into the AC territory. It is anticipated that these findings will have important implications for the future design of biomaterial-based scaffolds for nervous tissue repair.
Sujet(s)
Astrocytes , Neurites , Humains , Axones , Régénération nerveuse , Cicatrice/anatomopathologie , Cellules de Schwann/anatomopathologie , Cellules de Schwann/physiologie , Cellules de Schwann/transplantationRÉSUMÉ
BACKGROUND: Mobile health (mHealth) tools were developed during the past decades and are increasingly used by patients in cancer care too. Scientific research in the development of mHealth services is required in order to meet the various needs of patients and test usability. OBJECTIVE: The aim of this study is to assess patients' needs, preferences, and usability of an app (My University Clinic [MUC] app) developed by the Comprehensive Cancer Center Freiburg (CCCF) Germany. METHODS: Based on a qualitative cross-sectional approach, we conducted semistructured interviews with patients with cancer, addressing their needs, preferences, and usability of the designed MUC app. Patients treated by the CCCF were recruited based on a purposive sampling technique focusing on age, sex, cancer diagnoses, and treatment setting (inpatient, outpatient). Data analysis followed the qualitative content analysis according to Kuckartz and was performed using computer-assisted software (MAXQDA). RESULTS: For the interviews, 17 patients with cancer were selected, covering a broad range of sampling parameters. The results showed that patients expect benefits in terms of improved information about the disease and communication with the clinic staff. Demands for additional features were identified (eg, a list of contact persons and medication management). The most important concerns referred to data security and the potential restriction of personal contacts with health care professionals of the clinical departments of the CCCF. In addition, some features for improving the design of the MUC app with respect to usability or for inclusion of interacting tools were suggested by the patients. CONCLUSIONS: The results of this qualitative study were discussed within the multidisciplinary team and the MUC app providers. Patients' perspectives and needs will be included in further development of the MUC app. There will be a second study phase in which patients will receive a test version of the MUC app and will be asked about their experiences with it. TRIAL REGISTRATION: Deutsches Register Klinischer Studien DRKS00022162; https://drks.de/search/de/trial/DRKS00022162.
RÉSUMÉ
OBJECTIVE: More than one in 10 cancer patients care for dependent children. It is unclear whether this status makes a difference in terms of the distress and associated problems they experience, or whether it is linked to differences in the need for or utilization of psychosocial support. METHODS: Secondary analysis of a cross-sectional German study in National Comprehensive Cancer Centers using self-report standardized questionnaires administered to inpatients. Patients living with dependent children (n = 161) were matched by age and sex with a subsample of 161 cancer patients not living with dependent children. The resulting sample was tested for between-group differences in Distress Thermometer (DT) scores and the corresponding DT Problem List. Additionally, between-group differences in measures of the need for and utilization of psychosocial support were examined. RESULTS: More than 50% of all patients suffered from clinically relevant distress. Patients living with dependent children reported significantly more practical (p < 0.001, η2 p = 0.04), family (p < 0.001, η2 p = 0.03), and emotional problems (p < 0.001, η2 p = 0.01). Although reporting a greater need for psychological support, parents with cancer were not found to more frequently utilize any type of psychosocial support. CONCLUSIONS: The specific problems and needs of parents with cancer who care for dependent children are currently not sufficiently addressed in the clinical care pathways. All families should be helped to establish open and honest communication as well as understand the available support systems and what they can provide. Tailored interventions should be implemented for highly distressed families.
Sujet(s)
Dysfonctionnement cognitif , Tumeurs , Humains , Enfant , Stress psychologique/psychologie , Études transversales , Parents , Anxiété , Tumeurs/thérapie , Tumeurs/psychologieRÉSUMÉ
Filamin-A-interacting protein 1 (FILIP1) is a structural protein that is involved in neuronal and muscle function and integrity and interacts with FLNa and FLNc. Pathogenic variants in filamin-encoding genes have been linked to neurological disorders (FLNA) and muscle diseases characterized by myofibrillar perturbations (FLNC), but human diseases associated with FILIP1 variants have not yet been described. Here, we report on five patients from four unrelated consanguineous families with homozygous FILIP1 variants (two nonsense and two missense). Functional studies indicated altered stability of the FILIP1 protein carrying the p.[Pro1133Leu] variant. Patients exhibit a broad spectrum of neurological symptoms including brain malformations, neurodevelopmental delay, muscle weakness and pathology and dysmorphic features. Electron and immunofluorescence microscopy on the muscle biopsy derived from the patient harbouring the homozygous p.[Pro1133Leu] missense variant revealed core-like zones of myofibrillar disintegration, autophagic vacuoles and accumulation of FLNc. Proteomic studies on the fibroblasts derived from the same patient showed dysregulation of a variety of proteins including FLNc and alpha-B-crystallin, a finding (confirmed by immunofluorescence) which is in line with the manifestation of symptoms associated with the syndromic phenotype of FILIP1opathy. The combined findings of this study show that the loss of functional FILIP1 leads to a recessive disorder characterized by neurological and muscular manifestations as well as dysmorphic features accompanied by perturbed proteostasis and myopathology.
Sujet(s)
Maladies musculaires , Protéomique , Humains , Filamines/génétique , Mutation/génétique , Maladies musculaires/génétique , Faiblesse musculaire , Protéines de transport/génétique , Protéines du cytosquelette/génétiqueRÉSUMÉ
Membrane-shaping proteins characterized by reticulon homology domains play an important part in the dynamic remodelling of the endoplasmic reticulum (ER). An example of such a protein is FAM134B, which can bind LC3 proteins and mediate the degradation of ER sheets through selective autophagy (ER-phagy)1. Mutations in FAM134B result in a neurodegenerative disorder in humans that mainly affects sensory and autonomic neurons2. Here we report that ARL6IP1, another ER-shaping protein that contains a reticulon homology domain and is associated with sensory loss3, interacts with FAM134B and participates in the formation of heteromeric multi-protein clusters required for ER-phagy. Moreover, ubiquitination of ARL6IP1 promotes this process. Accordingly, disruption of Arl6ip1 in mice causes an expansion of ER sheets in sensory neurons that degenerate over time. Primary cells obtained from Arl6ip1-deficient mice or from patients display incomplete budding of ER membranes and severe impairment of ER-phagy flux. Therefore, we propose that the clustering of ubiquitinated ER-shaping proteins facilitates the dynamic remodelling of the ER during ER-phagy and is important for neuronal maintenance.
Sujet(s)
Autophagie , Stress du réticulum endoplasmique , Réticulum endoplasmique , Protéines ubiquitinées , Ubiquitination , Animaux , Humains , Souris , Autophagie/génétique , Réticulum endoplasmique/métabolisme , Protéines et peptides de signalisation intracellulaire/déficit , Protéines et peptides de signalisation intracellulaire/génétique , Protéines et peptides de signalisation intracellulaire/métabolisme , Protéines membranaires/déficit , Protéines membranaires/génétique , Protéines membranaires/métabolisme , Protéines ubiquitinées/métabolisme , Cellules réceptrices sensorielles/métabolisme , Cellules réceptrices sensorielles/anatomopathologie , Membranes intracellulaires/métabolismeRÉSUMÉ
The retinal degeneration 10 (rd10) mouse model is widely used to study retinitis pigmentosa (RP) pathomechanisms. It offers a rather unique opportunity to study trans-neuronal degeneration because the cell populations in question are separated anatomically and the mutated Pde6b gene is selectively expressed in rod photoreceptors. We hypothesized that RNA binding protein (RBP) aggregation and abnormal autophagy might serve as early pathogenic events, damaging non-photoreceptor retinal cell types that are not primarily targeted by the Pde6b gene defect. We used a combination of immunohistochemistry (DAB, immunofluorescence), electron microscopy (EM), subcellular fractionation, and Western blot analysis on the retinal preparations obtained from both rd10 and wild-type mice. We found early, robust increases in levels of the protective endoplasmic reticulum (ER) calcium (Ca2+) buffering chaperone Sigma receptor 1 (SigR1) together with other ER-Ca2+ buffering proteins in both photoreceptors and non-photoreceptor neuronal cells before any noticeable photoreceptor degeneration. In line with this, we found markedly altered expression of the autophagy proteins p62 and LC3, together with abnormal ER widening and large autophagic vacuoles as detected by EM. Interestingly, these changes were accompanied by early, prominent cytoplasmic and nuclear aggregation of the key RBPs including pTDP-43 and FET family RBPs and stress granule formation. We conclude that progressive neurodegeneration in the rd10 mouse retina is associated with early disturbances of proteostasis and autophagy, along with abnormal cytoplasmic RBP aggregation.
Sujet(s)
Dégénérescence de la rétine , Rétinite pigmentaire , Souris , Animaux , Dégénérescence de la rétine/anatomopathologie , Rétinite pigmentaire/génétique , Homéostasie , Autophagie , Protéines de liaison à l'ARNRÉSUMÉ
Proteins of the secretory pathway undergo glycosylation in the endoplasmic reticulum (ER) and the Golgi apparatus. Altered protein glycosylation can manifest in serious, sometimes fatal malfunctions. We recently showed that mutations in GDP-mannose pyrophosphorylase A (GMPPA) can cause a syndrome characterized by alacrima, achalasia, mental retardation, and myopathic alterations (AAMR syndrome). GMPPA acts as a feedback inhibitor of GDP-mannose pyrophosphorylase B (GMPPB), which provides GDP-mannose as a substrate for protein glycosylation. Loss of GMPPA thus enhances the incorporation of mannose into glycochains of various proteins, including α-dystroglycan (α-DG), a protein that links the extracellular matrix with the cytoskeleton. Here, we further characterized the consequences of loss of GMPPA for the secretory pathway. This includes a fragmentation of the Golgi apparatus, which comes along with a regulation of the abundance of several ER- and Golgi-resident proteins. We further show that the activity of the Golgi-associated endoprotease furin is reduced. Moreover, the fraction of α-DG, which is retained in the ER, is increased. Notably, WT cells cultured at a high mannose concentration display similar changes with increased retention of α-DG, altered structure of the Golgi apparatus, and a decrease in furin activity. In summary, our data underline the importance of a balanced mannose homeostasis for the secretory pathway.
RÉSUMÉ
In the diagnosis of diseases of the central and peripheral nervous systems, the use of electron microscopic analyses has become rare these days. However, there are questions in which the method is helpful in confirming the etiopathogenesis of the disease. Hereditary neurodegenerative and metabolic diseases, such as the lysosomal storage disease neuronal ceroid lipofuscinosis, are associated with pathognomonic storage products not only in the central nervous system (CNS) but also in extracerebral tissues such as sweat glands and lymphocytes. These tissues are easily accessible and thus function as "windows to the CNS". In addition, there are new methods that overcome limitations of conventional electron microscopy and may improve ultrastructural diagnostics. This is particularly important for the correct classification of viral particles such as SARS-CoV2, leading to a better understanding of COVID19-associated diseases in the CNS and peripheral nervous system.