Proteasome dysfunction in T cells causes immunodeficiency via cell cycle disruption and apoptosis
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE291117 | GEO | 2025/05/19
REPOSITORIES: GEO
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Project description:The proteasome plays a pivotal role in protein degradation, and its impairment is associated with various pathological conditions, including neurodegenerative diseases. It is well understood that Nrf1 coordinates the induction of all proteasome genes in response to proteasome dysfunction. However, the molecular mechanism regulating the basal expression of the proteasome remains unclear. Here we identified the transcription factor THAP1, the causative gene of DYT6 dystonia, as a regulator of proteasome activity through genome-wide genetic screens. We demonstrated that THAP1 directly regulates the expression of the PSMB5 gene, which encodes the central protease subunit β5. Depletion of THAP1 disrupted proteasome assembly, leading to reduced proteasome activity and the accumulation of ubiquitinated proteins. These findings reveal a new regulatory mechanism for the proteasome and suggest a potential role for proteasome dysfunction in the pathogenesis of dystonia.
2025-01-13 | GSE283266 | GEO
Project description:J774 cells were treated with MG132, epoxomicin and ONX-0912 for 4 hours, and gene expression was evaluated In order to evaluate the molecular mechanism of inflammatory responses in PRAAS(Proteasome-Associated Autoinflammatory Syndromes ), we established Psmb8-KI mouse that harbors the same mutation in human patients. Psmb8-KI mice showed higher susceptibility to imiquimod-induced skin inflammation (IMS). DNA microarray analysis showed that treatment of J774 cells with proteasome inhibitors increased the expression of the Cxcl9 and Cxcl10 genes, and the skins where imiquimod was painted also expressed both genes at higher levels in Psmb8-KI than control mice. Deficiency in Cxcr3, the gene encoding the receptor of CXCL9 and CXCL10, in wild-type mice did not change IMS susceptibility, while deficiency in Cxcr3 in Psmb8-KI mice ameliorated IMS.
2022-04-01 | GSE189308 | GEO
Project description:The 26S proteasome is a multi-catalytic protease that serves as the endpoint for protein degradation via the ubiquitin-proteasome system. Proteasome function requires the concerted activity of 33 distinct gene products, but how the expression of proteasome subunits is regulated in mammalian cells remains poorly understood. Leveraging coessentiality data from the DepMap project, here we characterize an essential role for the Dystonia gene THAP1 in maintaining the basal expression of PSMB5. PSMB5 insufficiency resulting from loss of THAP1 leads to defects in proteasome assembly, impaired proteostasis and cell death. The toxicity associated with loss of THAP1 can be rescued upon exogenous expression of PSMB5, explaining the molecular basis for their coessentiality. Leveraging a fluorescent reporter knocked-in to the endogenous PSMB5 locus, we define the transcriptional targets of THAP1 through RNA-seq analysis and perform a deep mutational scan to systematically assess the function of thousands of single amino acid THAP1 variants. Altogether, these data identify THAP1 as a new regulator of proteasome function and suggest that aberrant proteostasis may contribute to the pathogenesis of THAP1 Dystonias.
2025-01-18 | GSE264536 | GEO
Project description:Objective: In idiopathic inflammatory myopathies (IIM) infiltration of immune cells into muscle and upregulation of MHC-I expression implies increased antigen presentation and involvement of the proteasome system. To decipher the role of immunoproteasomes in myositis, we investigated individual cell types and muscle tissues and focused on possible immune triggers. Methods: Expression of constitutive (PSMB5, -6, -7) and corresponding immunoproteasomal subunits (PSMB8, -9, -10) was analyzed by real-time RT-PCR in muscle biopsies and sorted peripheral blood cells of patients with IIM, non-inflammatory myopathies (NIM) and healthy donors (HD). Protein analysis in muscle biopsies was performed by western blot. Affymetrix HG-U133 platform derived transcriptome data from biopsies of different muscle diseases and from immune cell types as well as monocyte stimulation experiments were used for validation, coregulation and coexpression analyses. Results: Real-time RT-PCR revealed significantly increased expression of immunoproteasomal subunits (PSMB8/-9/-10) in DC, monocytes and CD8+ T-cells in IIM. In muscle biopsies, the immunosubunits were elevated in IIM compared to NIM and exceeded levels of matched blood samples. Proteins of PSMB8 and -9 were found only in IIM but not NIM muscle biopsies. Reanalysis of 78 myositis and 20 healthy muscle transcriptomes confirmed these results and revealed involvement of the antigen processing and presentation pathway. Comparison with reference profiles of sorted immune cells and healthy muscle confirmed upregulation of PSMB8 and -9 in myositis biopsies beyond infiltration related changes. This upregulation correlated highest with STAT1, IRF1 and IFNM-NM-3 expression. Elevation of T-cell specific transcripts in active IIM muscles was accompanied by increased expression of DC and monocyte marker genes and thus reflects the cell type specific involvement observed in peripheral blood. Conclusions: Immunoproteasomes seem to indicate IIM activity and suggest that dominant involvement of antigen processing and presentation may qualify these diseases exemplarily for the evolving therapeutic concepts of immunoproteasome specific inhibition. Investigation of constitutive and immunoproteasomal subunit expression in muscle tissue of patients with inflammatory and non-inflammatory myopathies These transcriptomes were used as reference signatures of different immune cell types in order to estimate the contribution of immune cell transcripts to the muscle transcriptomes investigated in the datasets GSE2044, GSE3112, GSE5370, GSE39454, GSE3307, GSE13205, GSE10685.
2014-06-04 | E-GEOD-58173 | biostudies-arrayexpress
Project description:The stress proteasome in the animal kingdom facilitates faster conversion of oxidized proteins during stress conditions by incorporating different catalytic β subunits. Plants deal with similar kind of stresses and also carry multiple paralogous genes encoding for each of the three catalytic β subunits. Here we investigated the existence of stress proteasomes upon salt stress in tomato roots. In contrast to Arabidopsis thaliana, tomato has a simplified proteasome gene set with single genes encoding each β subunit except for two genes encoding β2. Using proteasome activity profiling on tomato roots during salt stress we discovered a transient modification of the catalytic subunits of the proteasome coinciding with a loss of viability. This stress-induced proteasome disappears at later time points and coincides with the need to degrade oxidized proteins during salt stress. Subunit-selective proteasome probes and MS analysis of fluorescent 2D gels demonstrated that the stress-induced proteasome is not caused by altered subunit assembly, but involves an increased molecular weight (MW) of both β2 and β5 subunits, and an additional acidic pI shift for β5, whilst β1 remains mostly unchanged. Although the underlying subunit modification is unknown, we can rule out ubiquitination, phosphorylation and glycosylation as underlying molecular mechanisms. This stress-induced proteasome may play an important role in PCD during abiotic stress.
2017-02-22 | PXD005266 | Pride
Project description:Proctor2007 - Age related decline of proteolysis, ubiquitin-proteome system
This
is a stochastic model of the ubiquitin-proteasome system for a
generic pool of native proteins (NatP), which have a half-life of
about 10 hours under normal conditions. It is assumed that these
proteins are only degraded after they have lost their native
structure due to a damage event. This is represented in the model
by the misfolding reaction which depends on the level of reactive
oxygen species (ROS) in the cell. Misfolded proteins (MisP) are
first bound by an E3 ubiquitin ligase. Ubiquitin (Ub) is
activated by E1 (ubiquitin-activating enzyme) and then passed to
E2 (ubiquitin-conjugating enzyme). The E2 enzyme then passes the
ubiquitin molecule to the E3/MisP complex with the net effect
that the misfolded protein is monoubiquitinated and both E2 and
E3 are released. Further ubiquitin molecules are added in a
step-wise manner. When the chain of ubiquitin molecules is of
length 4 or more, the polyubiquitinated misfolded protein may
bind to the proteasome. The model also includes de-ubiquitinating
enzymes (DUB) which cleave ubiquitin molecules from the chain in
a step-wise manner. They work on chains attached to misfolded
proteins both unbound and bound to the proteasomes. Misfolded
proteins bound to the proteasome may be degraded releasing
ubiquitin. Misfolded proteins including ubiquitinated proteins
may also aggregate. Aggregates (AggP) may be sequestered
(Seq_AggP) which takes them out of harm's way or they may bind to
the proteasome (AggP_Proteasome). Proteasomes bound by aggregates
are no longer available for protein degradation.
Figure
2 and Figure 3 has been simulated using Gillespie2.
This model is described in the article:
An in silico model of the
ubiquitin-proteasome system that incorporates normal
homeostasis and age-related decline.
Proctor CJ, Tsirigotis M, Gray
DA.
BMC Syst Biol 2007; 1: 17
Abstract:
BACKGROUND: The ubiquitin-proteasome system is responsible
for homeostatic degradation of intact protein substrates as
well as the elimination of damaged or misfolded proteins that
might otherwise aggregate. During ageing there is a decline in
proteasome activity and an increase in aggregated proteins.
Many neurodegenerative diseases are characterised by the
presence of distinctive ubiquitin-positive inclusion bodies in
affected regions of the brain. These inclusions consist of
insoluble, unfolded, ubiquitinated polypeptides that fail to be
targeted and degraded by the proteasome. We are using a systems
biology approach to try and determine the primary event in the
decline in proteolytic capacity with age and whether there is
in fact a vicious cycle of inhibition, with accumulating
aggregates further inhibiting proteolysis, prompting
accumulation of aggregates and so on. A stochastic model of the
ubiquitin-proteasome system has been developed using the
Systems Biology Mark-up Language (SBML). Simulations are
carried out on the BASIS (Biology of Ageing e-Science
Integration and Simulation) system and the model output is
compared to experimental data wherein levels of ubiquitin and
ubiquitinated substrates are monitored in cultured cells under
various conditions. The model can be used to predict the
effects of different experimental procedures such as inhibition
of the proteasome or shutting down the enzyme cascade
responsible for ubiquitin conjugation. RESULTS: The model
output shows good agreement with experimental data under a
number of different conditions. However, our model predicts
that monomeric ubiquitin pools are always depleted under
conditions of proteasome inhibition, whereas experimental data
show that monomeric pools were depleted in IMR-90 cells but not
in ts20 cells, suggesting that cell lines vary in their ability
to replenish ubiquitin pools and there is the need to
incorporate ubiquitin turnover into the model. Sensitivity
analysis of the model revealed which parameters have an
important effect on protein turnover and aggregation kinetics.
CONCLUSION: We have developed a model of the
ubiquitin-proteasome system using an iterative approach of
model building and validation against experimental data. Using
SBML to encode the model ensures that it can be easily modified
and extended as more data become available. Important aspects
to be included in subsequent models are details of ubiquitin
turnover, models of autophagy, the inclusion of a pool of
short-lived proteins and further details of the aggregation
process.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000105.
To cite BioModels Database, please use:
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To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
2024-09-02 | BIOMD0000000105 | BioModels
Project description:Objective: In idiopathic inflammatory myopathies (IIM) infiltration of immune cells into muscle and upregulation of MHC-I expression implies increased antigen presentation and involvement of the proteasome system. To decipher the role of immunoproteasomes in myositis, we investigated individual cell types and muscle tissues and focused on possible immune triggers. Methods: Expression of constitutive (PSMB5, -6, -7) and corresponding immunoproteasomal subunits (PSMB8, -9, -10) was analyzed by real-time RT-PCR in muscle biopsies and sorted peripheral blood cells of patients with IIM, non-inflammatory myopathies (NIM) and healthy donors (HD). Protein analysis in muscle biopsies was performed by western blot. Affymetrix HG-U133 platform derived transcriptome data from biopsies of different muscle diseases and from immune cell types as well as monocyte stimulation experiments were used for validation, coregulation and coexpression analyses. Results: Real-time RT-PCR revealed significantly increased expression of immunoproteasomal subunits (PSMB8/-9/-10) in DC, monocytes and CD8+ T-cells in IIM. In muscle biopsies, the immunosubunits were elevated in IIM compared to NIM and exceeded levels of matched blood samples. Proteins of PSMB8 and -9 were found only in IIM but not NIM muscle biopsies. Reanalysis of 78 myositis and 20 healthy muscle transcriptomes confirmed these results and revealed involvement of the antigen processing and presentation pathway. Comparison with reference profiles of sorted immune cells and healthy muscle confirmed upregulation of PSMB8 and -9 in myositis biopsies beyond infiltration related changes. This upregulation correlated highest with STAT1, IRF1 and IFNγ expression. Elevation of T-cell specific transcripts in active IIM muscles was accompanied by increased expression of DC and monocyte marker genes and thus reflects the cell type specific involvement observed in peripheral blood. Conclusions: Immunoproteasomes seem to indicate IIM activity and suggest that dominant involvement of antigen processing and presentation may qualify these diseases exemplarily for the evolving therapeutic concepts of immunoproteasome specific inhibition.
2014-06-04 | GSE58173 | GEO
Project description:Proteasomes degrade most intracellular proteins. Several different forms of proteasomes are known. Proteasome inhibitors targeting different proteasome forms are used in clinical practice and were shown to modulate long-term potentiation (LTP) in hippocampal slices of untreated animals. Here we studied the effect of chronic administration of non-constitutive proteasome inhibitor ONX-0914 on the LTP induced by two different protocols: tetanic stimulation and theta-burst stimulation (TBS). Excitatory postsynaptic potentials (fEPSPs) in hippocampal slices from control animals and animals treated with DMSO or ONX-0914 were compared. The TBS stimulation did not change LTP kinetics in hippocampal slices, however chronic administration of ONX-0914 led to the decrease in fEPSP slopes after tetanic stimulation. Observed effects correlated with differential expression of genes involved in synaptic plasticity, glutaminergic synapse and synaptic signaling. Obtained results indicate that non-constitutive proteasomes are likely involved in the tetanus-evoked LTP but not the LTP occurring after TBS, supporting the relevance and complexity of the role of proteasomes in the synaptic plasticity.
2023-04-05 | GSE229000 | GEO
Project description:As the major protein degradation machinery of eukaryotic cells, the 26S proteasome is generally thought to localize in the nucleus and cytosol. A portion of proteasomes are known to associate with various membrane structures of the cell, the mechanism and biological meaning of which have been elusive. Here we show that N-myristoylation of the proteasome subunit Rpt2 is an evolutionarily conserved determinant of proteasome-membrane interaction. Loss of this modification leads to embryonic lethality in mice, significant reduction of migration ability in MEFs and profound changes in the membrane-associated proteome as determined by SILAC-MS, suggesting a key role of membrane-tethered proteasomes in carrying out compartmentalized protein degradation. And the tumorigenicity is reduced in the oncogene-transformed MEF without modification. Serendipitously, we found that the Rpt2-G2A mutation cell lines confers partial resistance to proteasome inhibitors, such as Bortezomib and MG132. Thus, N-myristoylation of Rpt2 determines the localization and activity of the proteasome at the membrane, which is critical for embryogenesis, cellular homeostasis and tumorigenesis.
2023-05-16 | GSE232308 | GEO
Project description:Disruption in proteostasis is a hallmark of cancer, with aberrations in proteasome-mediated degradation highly implicated in this malignancy. Proteasomes further bear critical importance in tumor immunogenicity by regulating inflammatory signaling, promoting immune cell activation and playing a crucial role in antigen processing and presentation. Indeed, response to immunotherapy in melanoma patients has been recently linked to increased expression of immunoproteasomes, a specialized form of proteasomes that are upregulated under inflammatory conditions. Yet, the percentage of patients that respond to therapy remains low, and the underlying mechanisms driving resistance remain poorly understood. Further, comprehensive analysis of the role proteasomes play in the pathophysiology of cancer and as a modulator of anti-tumor immunity is remains lacking. Here, we show that proteasome complex composition varies across cancer types and can be used to stratify patient response to immunotherapy. Specifically, we found that the proteasome regulator PSME4 is upregulated in NSCLC and associated with poor prognosis. We show that PSME4 alters proteasome activity and antigen processing attenuating the antigenic diversity and presentation. Through exacting biochemical assays, proteasome profiling of patient-derived NSCLC samples, combined with scRNA-seq, immunopeptidomics and in vivo analyses we uncovered a novel mechanism of immune evasion mediated by PSME4, which promotes an immunosuppressive tumor microenvironment and abrogates anti-tumor immunity. Collectively, our approach may be adapted to other cancer types and pathological settings and affords a novel paradigm by which proteasome composition heterogeneity should be examined and targeted in the context of precision oncology.
2023-02-26 | GSE201460 | GEO