The role of charged multivesicular body protein 5 in programmed cell death in leukemic cells

CHMP5 attenuates osteoarthritis via inhibiting chondrocyte apoptosis and extracellular matrix degradation: involvement of NF-κB pathway

BACKGROUND

Osteoarthritis (OA), the most common joint disease, is linked with chondrocyte apoptosis and extracellular matrix (ECM) degradation. Charged multivesicular body protein 5 (CHMP5), a member of the multivesicular body, has been reported to serve as an anti-apoptotic protein to participate in leukemia development. However, the effects of CHMP5 on apoptosis and ECM degradation in OA remain unclear.

METHODS

In this study, quantitative proteomics was performed to analyze differential proteins between normal and OA patient articular cartilages. The OA mouse model was constructed by the destabilization of the medial meniscus (DMM). In vitro, interleukin-1 beta (IL-1β) was used to induce OA in human chondrocytes. CHMP5 overexpression and silencing vectors were created using an adenovirus system. The effects of CHMP5 on IL-1β-induced chondrocyte apoptosis were investigated by CCK-8, flow cytometry, and western blot. The effects on ECM degradation were examined by western blot and immunofluorescence. The potential mechanism was explored by western blot and Co-IP assays.

RESULTS

Downregulated CHMP5 was identified by proteomics in OA patient cartilages, which was verified in human and mouse articular cartilages. CHMP5 overexpression repressed cell apoptosis and ECM degradation in OA chondrocytes. However, silencing CHMP5 exacerbated OA chondrocyte apoptosis and ECM degradation. Furthermore, we found that the protective effect of CHMP5 against OA was involved in nuclear factor kappa B (NF-κB) signaling pathway.

CONCLUSIONS

This study demonstrated that CHMP5 repressed IL-1β-induced chondrocyte apoptosis and ECM degradation and blocked NF-κB activation. It was shown that CHMP5 might be a novel potential therapeutic target for OA in the future.

The ESCRT protein CHMP5 promotes T cell leukemia by controlling BRD4-p300-dependent transcription

Oncogene activity rewires cellular transcription, creating new transcription networks to which cancer cells become addicted, by mechanisms that are still poorly understood. Using human and mouse models of T cell acute lymphoblastic leukemia (T-ALL), we identify an essential nuclear role for CHMP5, a cytoplasmic endosomal sorting complex required for transport (ESCRT) protein, in establishing and maintaining the T-ALL transcriptional program. Nuclear CHMP5 promoted the T-ALL gene program by augmenting recruitment of the co-activator BRD4 by the histone acetyl transferase p300 selectively at enhancers and super-enhancers, an interaction that potentiated H3K27 acetylation at these regulatory enhancers. Consequently, loss of CHMP5 diminished BRD4 occupancy at enhancers and super-enhancers and impaired RNA polymerase II pause release, which resulted in downregulation of key T-ALL genes, notably MYC. Reinforcing its importance in T-ALL pathogenesis, CHMP5 deficiency mitigated chemoresistance in human T-ALL cells and abrogated T-ALL induction by oncogenic NOTCH1 in vivo. Thus, the ESCRT protein CHMP5 is an essential positive regulator of the transcriptional machinery promoting T-ALL disease.

Bioinformatics-led discovery of ferroptosis-associated diagnostic biomarkers and molecule subtypes for tuberculosis patients

BACKGROUND

Ferroptosis is closely associated with the pathophysiological processes of many diseases, such as infection, and is characterized by the accumulation of excess lipid peroxides on the cell membranes. However, studies on the ferroptosis-related diagnostic markers in tuberculosis (TB) is still lacking. Our study aimed to explore the role of ferroptosis-related biomarkers and molecular subtypes in TB.

METHODS

GSE83456 dataset was applied to identify ferroptosis-related genes (FRGs) associated with TB, and GSE42826, GSE28623, and GSE34608 datasets for external validation of core biomarkers. Core FRGs were identified using weighted gene co-expression network analysis (WGCNA). Subsequently, two ferroptosis-related subtypes were constructed based on ferroptosis score, and differently expressed analysis, GSEA, GSEA, immune cell infiltration analysis between the two subtypes were performed.Affiliations: Please check and confirm that the authors and their respective affiliations have been correctly identified and amend if necessary.correctly RESULTS: A total of 22 FRGs were identified, of which three genes (CHMP5, SAT1, ZFP36) were identified as diagnostic biomarkers that were enriched in pathways related to immune-inflammatory response. In addition, TB patients were divided into high- and low-ferroptosis subtypes (HF and LF) based on ferroptosis score. HF patients had activated immune- and inflammation-related pathways and higher immune cell infiltration levels than LF patients.

CONCLUSION

Three potential diagnostic biomarkers and two ferroptosis-related subtypes were identified in TB patients, which would help to understand the pathogenesis of TB.Author names: Kindly check and confirm the process of the author names [2,4]correctly.

A risk model developed based on necroptosis to assess progression for ischemic cardiomyopathy and identify possible therapeutic drugs

Object: Ischemic cardiomyopathy (ICM), with high morbidity and mortality, is the most common cause of heart failure. Cardiovascular remodeling secondary to chronic myocardial ischemia is the main cause of its progression. A recently identified type of programmed cell death called necroptosis is crucial in the development of various cardiovascular diseases. However, the function role of necroptosis in cardiac remodeling of ICM has not been elucidated. Our study aimed to screen for genes associated with necroptosis and construct a risk score to assess the progression and evaluate the prognosis of ICM patients, and further to search for potentially therapeutic drugs. Methods: The gene expression profiling was obtained from the GEO database. LASSO regression analysis was used to construct necroptosis-related gene signatures associated with ICM progression and prognosis. TF-gene and miRNA-gene networks were constructed to identify the regulatory targets of potential necroptosis-related signature genes. Pathway alterations in patients with high necroptosis-related score (NRS) were analyzed by GO, KEGG, GSEA analysis, and immune cell infiltration was estimated by ImmuCellAI analysis. CMap analysis was performed to screen potential small molecule compounds targeting patients with high NRS. Independent risk analyses were performed using nomograms. Results: Six necroptosis-related signature genes (STAT4, TNFSF10, CHMP5, CHMP18, JAK1, and CFLAR) were used to define the NRS, with areas under the ROC curves of 0.833, 0.765, and 0.75 for training test, test set, and validation set, respectively. Transcription factors FOXC1 and hsa-miR-124-3p miRNA may be regulators of signature genes. Patients with higher NRS have pathway enriched in fibrosis and metabolism and elevated nTreg cells. AZD-7762 may be an effective drug to improve the prognosis of patients with high NRS. A feature-based nomogram was constructed from which patients could derive clinical benefit. Conclusion: Our results reveal 6 necroptosis gene signatures that can evaluate the progression and prognosis of ICM with high clinical value, and identify potential targets that could help improve cardiovascular remodeling.

Mechanism of the growth and development of the posterior silk gland and silk secretion revealed by mutation of the fibroin light chain in silkworm

Silkworm, as a model organism, has very high economic value due to its silk secretion ability. Although a large number of studies have attempted to elucidate the mechanism of silk secretion, it remains unclear. In this study, the fibroin light chain (Fib-L) gene of silkworm was subjected to CRISPR/Cas9 editing, which yielded premature termination of translation at 135 aa. Compared with those of the wild type, the posterior silk glands (PSGs) of the homozygous mutants on the third day of the fifth instar showed obvious premature degeneration. Comparative transcriptome and proteomic analyses of the PSGs of wild-type individuals, heterozygous mutants and homozygous mutants were performed on the fourth day of the fifth instar. A GO enrichment analysis showed that the differentially expressed genes (DEGs) between homozygous mutants and wild-type individuals were enriched in cytoskeleton-related terms, and a KEGG enrichment analysis showed that the upregulated DEGs between homozygous mutants and wild-type individuals were enriched in the phagosome and apoptosis pathways. These results indicated that apoptosis was activated prematurely in the PSGs of homozygous mutants. Furthermore, autophagy and heat shock response were activated in the PSGs of homozygous mutants, as demonstrated by an analysis of the DEGs related to autophagy and heat shock. A comparative proteomic analysis further confirmed that autophagy, apoptosis and the heat shock response were activated in the PSGs of homozygous mutants, which led to premature degradation of the PSGs. These results provide insights for obtaining a more in-depth understanding of the mechanism of silk secretion in silkworms.

Charged MVB protein 5 is involved in T-cell receptor signaling

Charged multivesicular body protein 5 (CHMP5) has a key role in multivesicular body biogenesis and a critical role in the downregulation of signaling pathways through receptor degradation. However, the role of CHMP5 in T-cell receptor (TCR)–mediated signaling has not been previously investigated. In this study, we utilized a short hairpin RNA-based RNA interference approach to investigate the functional role of CHMP5. Upon TCR stimulation, CHMP5-knockdown (CHMP5^KD) Jurkat T cells exhibited activation of TCR downstream signaling molecules, such as PKCθ and IKKαβ, and resulted in the activation of nuclear factor-κB and the marked upregulation of TCR-induced gene expression. Moreover, we found that activator protein-1 and nuclear factor of activated T-cells transcriptional factors were markedly activated in CHMP5^KD Jurkat cells in response to TCR stimulation, which led to a significant increase in interleukin-2 secretion. Biochemical studies revealed that CHMP5 endogenously forms high-molecular-weight complexes, including TCR molecules, and specifically interacts with TCRβ. Interestingly, flow cytometry analysis also revealed that CHMP5^KD Jurkat T cells exhibit upregulation of TCR expression on the cell surface compared with control Jurkat T cells. Taken together, these findings demonstrated that CHMP5 might be involved in the homeostatic regulation of TCR on the cell surface, presumably through TCR recycling or degradation. Thus CHMP5 is implicated in TCR-mediated signaling.

GAS2-Calpain2 axis contributes to the growth of leukemic cells

Growth arrest specific 2 (GAS2) modulates cell cycle, apoptosis, and Calpain activity. GAS2-Calpain2 axis is required for the growth of BCR-ABL(+) hematopoietic cells and chronic myeloid leukemia cells. However, the expression of GAS2 in acute leukemia patients remains unclear and what role GAS2-Calpain2 axis plays in these leukemic cells is not known yet. In this study, GAS2 was found to have significantly higher expression in 16 various leukemic cell lines than in control cells. Using THP-1 cells (from acute myeloid leukemia patient, AML) and Jurkat cells (from acute lymphoid leukemia patient, ALL) as models, we found that GAS2 silence led to elevated Calpain activity, decreased cellular growth, and inhibition of colony-forming cell (CFC) production; and these effects could be rescued by GAS2 re-expression. Moreover, GAS2 silence prevented tumor formation of THP-1 cells in nude mice. In both THP-1 and Jurkat cells, GAS2 interacted with Calpain2 rather than Calpain1. The dominant negative form of GAS2 (GAS2DN, GAS2Δ171-313) had similar effects on leukemic cells through the activation of Calpain. Importantly, Calpain2 silence abolished the proliferation inhibition induced by GAS2 targeting. We also found that GAS2 was aberrantly expressed and Calpain activity was decreased in clinical isolates from acute leukemia patients. Taken together, our results demonstrated the deregulation of GAS2 in both AML and ALL and the requirement of GAS2-Calpain2 axis for the growth of leukemic cells, which will help to understand the molecular pathogenesis of hematological malignancies and possibly to develop novel approaches to treat these deadly diseases.

Identification of Newly Synthesized Proteins by Echinococcus granulosus Protoscoleces upon Induction of Strobilation

Background

The proteins responsible for the key molecular events leading to the structural changes between the developmental stages of Echinococcus granulosus remain unknown. In this work, azidohomoalanine (AHA)-specific labeling was used to identify proteins expressed by E. granulosus protoscoleces (PSCs) upon the induction of strobilar development.

Methodology/Principal Findings

The in vitro incorporation of AHA with different tags into newly synthesized proteins (NSPs) by PSCs was analyzed using SDS-PAGE and confocal microscopy. The LC-MS/MS analysis of AHA-labeled NSPs by PSCs undergoing strobilation allowed for the identification of 365 proteins, of which 75 were differentially expressed in comparison between the presence or absence of strobilation stimuli and 51 were expressed exclusively in either condition. These proteins were mainly involved in metabolic, regulatory and signaling processes.

Conclusions/Significance

After the controlled-labeling of proteins during the induction of strobilar development, we identified modifications in protein expression. The changes in the metabolism and the activation of control and signaling pathways may be important for the correct parasite development and be target for further studies.

In the life cycle of the parasite Echinococcus granulosus, hydatid cysts produce the pre-adult form, which has the ability to either differentiate into an adult worm (strobilation) or dedifferentiate into a secondary hydatid cyst. We used different protein tags that allowed for the visualization and purification of proteins produced specifically after the induction of strobilar development to identify proteins that might be involved in this process (temporally controlled and context-dependent). As a result, we found proteins that are involved in important processes during development, such as energy metabolism, control pathways and cellular communication. We believe that these results will be useful for the development of scientific approaches to controlling and preventing cystic hydatid disease.

LncRNA expression profiles and validation in keloid and normal skin tissue

Keloid is a type of pathological skin scar. Pathogenesis of keloid is complex and is not fully understood. lncRNA can regulate gene expression on different levels. It also participates in cell cycle regulation and cell proliferation. The present study investigated the potential biological function of lncRNA in keloid. We identified differential expression of lncRNAs and mRNAs between 3 pairs of keloid and normal skin tissue by microarray. Differentially expressed lncRNAs were validated by quantitative reverse transcriptase-PCR (qRT-PCR). Gene ontology (GO) and pathway analysis presented the characteristics of associated protein-coding genes. Additionally, a co-expression network of lncRNA and mRNA was constructed to find potential underlying regulation targets. There were 1,731 lncRNAs constantly upregulated and 782 downregulated, 1,079 mRNAs upregulated and 3,282 downregulated in keloid respectively (fold change ≥ 2.0, p<0.05). We chose, respectively, 3 upregulated and 1 downregulated lncRNA for qRT-PCR and results were consistent with microarray. Moreover, 11 pathways were related with upregulated transcripts and 44 with downregulated in keloid. The co-expression network revealed that one lncRNA was connected with numerous mRNAs, and vice versa. Furthermore, bioinformation analysis suggested that lncRNA CACNA1G-AS1 may be crucial to keloid formation. In conclusion, groups of lncRNAs were aberrantly expressed in keloid compared with normal skin tissue, which indicated that differentially expressed lncRNAs may play a key role in keloid formation. The present study provides new insights into keloid pathology and potential targets for treatment of keloid.