51 research outputs found

    Nucleoli and Promyelocytic Leukemia Protein (PML) bodies are phase separated nuclear protein quality control compartments for misfolded proteins

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    We uncovered a role for nucleoli and PML-bodies as phase-separated protein quality control organelles that compartmentalize protein quality control factors and misfolded proteins for their efficient clearance. Failure to dispose misfolded proteins converts nucleoli and PML-bodies into a solid state that immobilizes ubiquitin, limiting its recycling for genome integrity maintenance

    Effect of different drying methods and solvent ratios on biological activities of Phyllanthus acidus extracts

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    The main purpose of this study was to evaluate the antioxidant and α-glucosidase inhibitory activities of Phyllanthus acidus. The P. acidus fruits were dried using three different methods, namely oven (OD), air (AD) and freeze (FD) dryings and extracted with ethanol at different ratios (50 and 100%). The proximate analysis and total phenolic content (TPC) as well as free radical scavenging and α-glucosidase inhibitory activities were determined. The proximate analysis of P. acidus fruit indicated that all the dried samples contained potential nutrient contents. The highest TPC value, α-glucosidase inhibitory and antioxidant activities were observed for 50% ethanolic extract from OD method with TPC value of 28.39 mg GAE/g dried extract, IC50 value of 12.394 μg/mL and 64.17% inhibition, respectively. The study revealed that phenolic compounds could be the main contributors to the antioxidant and α-glucosidase inhibitory activities based on the Pearson correlation coefficients with R values of 95.0 and 73.8%, respectively. The study could provide scientific evidence for some folk uses in the treatment of diseases related to the production of reactive oxygen species and oxidative stress

    BAG3 Pro209 mutants associated with myopathy and neuropathy relocate chaperones of the CASA-complex to aggresomes

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    Three missense mutations targeting the same proline 209 (Pro209) codon in the co-chaperone Bcl2-associated athanogene 3 (BAG3) have been reported to cause distal myopathy, dilated cardiomyopathy or Charcot-Marie-Tooth type 2 neuropathy. Yet, it is unclear whether distinct molecular mechanisms underlie the variable clinical spectrum of the rare patients carrying these three heterozygous Pro209 mutations in BAG3. Here, we studied all three variants and compared them to the BAG3_Glu455Lys mutant, which causes dilated cardiomyopathy. We found that all BAG3_Pro209 mutants have acquired a toxic gain-of-function, which causes these variants to accumulate in the form of insoluble HDAC6- and vimentin-positive aggresomes. The aggresomes formed by mutant BAG3 led to a relocation of other chaperones such as HSPB8 and Hsp70, which, together with BAG3, promote the so-called chaperone-assisted selective autophagy (CASA). As a consequence of their increased aggregation-proneness, mutant BAG3 trapped ubiquitinylated client proteins at the aggresome, preventing their efficient clearance. Combined, these data show that all BAG3_Pro209 mutants, irrespective of their different clinical phenotypes, are characterized by a gain-of-function that contributes to the gradual loss of protein homeostasis

    Defective ribosomal products challenge nuclear function by impairing nuclear condensate dynamics and immobilizing ubiquitin

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    Nuclear protein aggregation has been linked to genome instability and disease. The main source of aggregation-prone proteins in cells is defective ribosomal products (DRiPs), which are generated by translating ribosomes in the cytoplasm. Here, we report that DRiPs rapidly diffuse into the nucleus and accumulate in nucleoli and PML bodies, two membraneless organelles formed by liquid\u2013liquid phase separation. We show that nucleoli and PML bodies act as dynamic overflow compartments that recruit protein quality control factors and store DRiPs for later clearance. Whereas nucleoli serve as constitutive overflow compartments, PML bodies are stress-inducible overflow compartments for DRiPs. If DRiPs are not properly cleared by chaperones and proteasomes due to proteostasis impairment, nucleoli undergo amyloidogenesis and PML bodies solidify. Solid PML bodies immobilize 20S proteasomes and limit the recycling of free ubiquitin. Ubiquitin depletion, in turn, compromises the formation of DNA repair compartments at fragile chromosomal sites, ultimately threatening cell survival

    Small heat-shock protein HSPB3 promotes myogenesis by regulating the lamin B receptor

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    One of the critical events that regulates muscle cell differentiation is the replacement of the lamin B receptor (LBR)-tether with the lamin A/C (LMNA)-tether to remodel transcription and induce differentiation-specific genes. Here, we report that localization and activity of the LBR-tether are crucially dependent on the muscle-specific chaperone HSPB3 and that depletion of HSPB3 prevents muscle cell differentiation. We further show that HSPB3 binds to LBR in the nucleoplasm and maintains it in a dynamic state, thus promoting the transcription of myogenic genes, including the genes to remodel the extracellular matrix. Remarkably, HSPB3 overexpression alone is sufficient to induce the differentiation of two human muscle cell lines, LHCNM2 cells, and rhabdomyosarcoma cells. We also show that mutant R116P-HSPB3 from a myopathy patient with chromatin alterations and muscle fiber disorganization, forms nuclear aggregates that immobilize LBR. We find that R116P-HSPB3 is unable to induce myoblast differentiation and instead activates the unfolded protein response. We propose that HSPB3 is a specialized chaperone engaged in muscle cell differentiation and that dysfunctional HSPB3 causes neuromuscular disease by deregulating LBR

    Identification of new HSPB8 variants linked to familial Amiotrophic Lateral Sclerosis

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    The Heat Shock Protein B8 (HSPB8) is a small heat shock protein involved in the proteostasis network. HSPB8, with its obligatory partner BAG3, promotes the removal of misfolded proteins and protein aggregates, via autophagy. We have demonstrated that the overexpression of HSPB8 enhances the clearance of soluble and insoluble form of mutated SOD1, the C-terminal TDP-43 fragments and RAN translated dipeptide of the C9ORF72 repeats, causative of Amyotrophic Lateral Sclerosis (ALS). Interestingly, mutations in HSPB8 (K141E/N/T) are found in diseases that affect neurons and muscle cells, like distal hereditary motor neuropathy type II and Charcot Marie Tooth (CMT) disease type2L. Using exome sequencing (NGS) on a large cohort of fALS patients, available at the Istituto Auxologico Italiano, novel HSPB8 gene variants predicted to be pathogenic in fALS have been identified. We performed preliminary studies aimed to characterize the behaviour of these new variants compared to the wild type form. We found that one of the ALS-associated HSPB8 variants: i) affects the capability of endogenous HSPB8 to bind to its partner BAG3 (required for HSPB8 stabilization and functions); ii) correlates with a reduced stability, although no changes of HSPB8 solubility was found; ii) presents an altered mobility in native Gel Electrophoresis, iv) reduces the pro-degradative power of HSPB8 on TDP-43 and mutant SOD1. These data strongly indicate that the novel HSPB8 variant may be involved in fALS pathogenesis

    Developing rights-based standards for children having tests, treatments, examinations and interventions: using a collaborative, multi-phased, multi-method and multi-stakeholder approach to build consensus.

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    Children continue to experience harm when undergoing clinical procedures despite increased evidence of the need to improve the provision of child-centred care. The international ISupport collaboration aimed to develop standards to outline and explain good procedural practice and the rights of children within the context of a clinical procedure. The rights-based standards for children undergoing tests, treatments, investigations, examinations and interventions were developed using an iterative, multi-phased, multi-method and multi-stakeholder consensus building approach. This consensus approach used a range of online and face to face methods across three phases to ensure ongoing engagement with multiple stakeholders. The views and perspectives of 203 children and young people, 78 parents and 418 multi-disciplinary professionals gathered over a two year period (2020-2022) informed the development of international rights-based standards for the care of children having tests, treatments, examinations and interventions. The standards are the first to reach international multi-stakeholder consensus on definitions of supportive and restraining holds.    Conclusion: This is the first study of its kind which outlines international rights-based procedural care standards from multi-stakeholder perspectives. The standards offer health professionals and educators clear evidence-based tools to support discussions and practice changes to challenge prevailing assumptions about holding or restraining children and instead encourage a focus on the interests and rights of the child. What is Known: • Children continue to experience short and long-term harm when undergoing clinical procedures despite increased evidence of the need to improve the provision of child-centred care. • Professionals report uncertainty and tensions in applying evidence-based practice to children's procedural care. What is New: • This is the first study of its kind which has developed international rights-based procedural care standards from multi-stakeholder perspectives. • The standards are the first to reach international multi-stakeholder consensus on definitions of supportive and restraining holds

    Developing rights-based standards for children having tests, treatments, examinations and interventions: using a collaborative, multi-phased, multi-method and multi-stakeholder approach to build consensus.

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    Children continue to experience harm when undergoing clinical procedures despite increased evidence of the need to improve the provision of child-centred care. The international ISupport collaboration aimed to develop standards to outline and explain good procedural practice and the rights of children within the context of a clinical procedure. The rights-based standards for children undergoing tests, treatments, investigations, examinations and interventions were developed using an iterative, multi-phased, multi-method and multi-stakeholder consensus building approach. This consensus approach used a range of online and face to face methods across three phases to ensure ongoing engagement with multiple stakeholders. The views and perspectives of 203 children and young people, 78 parents and 418 multi-disciplinary professionals gathered over a two year period (2020-2022) informed the development of international rights-based standards for the care of children having tests, treatments, examinations and interventions. The standards are the first to reach international multi-stakeholder consensus on definitions of supportive and restraining holds. Conclusion: This is the first study of its kind which outlines international rights-based procedural care standards from multi-stakeholder perspectives. The standards offer health professionals and educators clear evidence-based tools to support discussions and practice changes to challenge prevailing assumptions about holding or restraining children and instead encourage a focus on the interests and rights of the child. What is Known: • Children continue to experience short and long-termharm when undergoing clinical procedures despite increased evidence of the need to improve the provision of child-centred care. • Professionals report uncertainty and tensions in applying evidence-based practice to children's procedural care. What is New: • This is the first study of its kind which has developed international rights-based procedural care standards from multi-stakeholder perspectives. • The standards are the first to reach international multi-stakeholder consensus on definitions of supportive and restraining holds. [Abstract copyright: © 2023. The Author(s).

    Developing rights-based standards for children having tests, treatments, examinations and interventions: using a collaborative, multi-phased, multi-method and multi-stakeholder approach to build consensus

    Get PDF
    Children continue to experience harm when undergoing clinical procedures despite increased evidence of the need to improve the provision of child-centred care. The international ISupport collaboration aimed to develop standards to outline and explain good procedural practice and the rights of children within the context of a clinical procedure. The rights-based standards for children undergoing tests, treatments, investigations, examinations and interventions were developed using an iterative, multi-phased, multi-method and multi-stakeholder consensus building approach. This consensus approach used a range of online and face to face methods across three phases to ensure ongoing engagement with multiple stakeholders. The views and perspectives of 203 children and young people, 78 parents and 418 multi-disciplinary professionals gathered over a two year period (2020-2022) informed the development of international rights-based standards for the care of children having tests, treatments, examinations and interventions. The standards are the first to reach international multi-stakeholder consensus on definitions of supportive and restraining holds.Conclusion: This is the first study of its kind which outlines international rights-based procedural care standards from multi-stakeholder perspectives. The standards offer health professionals and educators clear evidence-based tools to support discussions and practice changes to challenge prevailing assumptions about holding or restraining children and instead encourage a focus on the interests and rights of the child
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