Biochimica et biophysica acta. Molecular cell research最新文献

Hepatocellular carcinoma (HCC), the leading cause of cancer-related deaths worldwide, is characterised by rapid growth and marked invasiveness. Accumulating evidence suggests that deubiquitinases play a pivotal role in HCC growth and metastasis. However, the expression of the deubiquitinase FAM188B and its biological functions in HCC remain unknown. The aim of our study was to investigate the potential role of FAM188B in HCC. The expression of FAM188B was significantly upregulated in liver cancer cells compared to normal liver cells, both at the transcriptional and translational levels. Similarly, FAM188B expression was higher in liver cancer tissues than in normal liver tissues. Bioinformatic analysis revealed that high FAM188B expression was associated with poor prognosis in patients with HCC. We further demonstrated that FAM188B knockdown inhibited cell proliferation, epithelial-mesenchymal transition, migration and invasion both in vitro and in vivo. Mechanistically, FAM188B knockdown significantly inhibited the hnRNPA1/PKM2 pathway in HCC cells. FAM188B may inhibit ubiquitin-mediated degradation of hnRNPA1 through deubiquitination. Notably, we observed that the inhibitory effects of FAM188B knockdown on HCC cell proliferation, migration and invasion were reversed when hnRNPA1 expression was restored. In conclusion, FAM188B promotes HCC progression by enhancing the deubiquitination of hnRNPA1 and subsequently activating the hnRNPA1/PKM2 pathway. Therefore, targeting FAM188B is a potential strategy for HCC therapy.

The Endoplasmic Reticulum is a pervasive, dynamic cellular organelle that performs a wide range of functions in the eukaryotic cell, including protein folding and maturation. Upon stress, ER activates an adaptive cellular pathway, namely Unfolded Protein Response, that transduces information from ER to nucleus, restoring homeostasis in the ER milieu. UPR consists of three membrane-tethered sensors; IRE1, PERK and ATF6. Among all the UPR sensors, the IRE1 branch acts as a central pathway that orchestrates several pathways to determine cell fate. However, the detailed knowledge underlying the whole process is not understood yet. Previously, we determined the sMEK1 as one of the interacting partners of IRE1. sMEK1 is a protein phosphatase, which has been indicated in a number of critical cellular functions like apoptosis, cell proliferation, and tumour suppression. In this study, we evaluated the role of sMEK1 on the IRE1 signalling pathway. Our data indicate that sMEK1 can inhibit IRE1 phosphorylation under ER stress. This inhibitory effect of sMEK1 could be reflected in its downstream effectors, Xbp1 and RIDD, which are downregulated in the presence of sMEK1. We also found that the repressing effect of sMEK1 was specific to the IRE1 signalling pathway and could be preserved even under prolonged ER stress. Our findings also indicate that sMEK1 can inhibit IRE1 and its downstream molecules under ER stress irrespective of other UPR sensors. These results help to draw the mechanistic details giving insights into different molecular connections of UPR with other pathways.

The regulatory mechanism of the transcription factor GATA3 in the differentiation and maturation process of extravillous trophoblasts (EVT) in early pregnancy placenta, as well as its relevance to the occurrence of pregnancy disorders, remains poorly understood. This study leveraged single-cell RNA sequencing data from placental organoid models and placental tissue to explore the dynamic changes in GATA3 expression during EVT maturation. The expression pattern exhibited an initial upregulation followed by subsequent downregulation, with aberrant GATA3 localization observed in cases of recurrent miscarriage (RM). By identifying global targets regulated by GATA3 in primary placental EVT cells, JEG3, and HTR8/SVneo cell lines, this study offered insights into its regulatory mechanisms across different EVT cell models. Shared regulatory targets among these cell types and activation of trophoblast cell marker genes emphasized the importance of GATA3 in EVT differentiation and maturation. Knockdown of GATA3 in JEG3 cells led to repression of GATA3-induced epithelial-mesenchymal transition (EMT), as evidenced by changes in marker gene expression levels and enhanced migration ability. Additionally, interference with GATA3 accelerated cellular senescence, as indicated by reduced proliferation rates and increased activity levels for senescence-associated β-galactosidase enzyme, along with elevated expression levels for senescence-associated genes. This study provides comprehensive insights into the dual role of GATA3 in regulating EMT and cellular senescence during EVT differentiation, shedding light on the dynamic changes in GATA3 expression in normal and pathological placental conditions.

Objective

Intervertebral disc degeneration (IVDD) is the leading cause of lower back pain (LBP). β-arrestin 1 (ARRB1) is a multifunctional protein that regulates numerous pathological processes. The aim of this study was to investigate the role of ARRB1 in IVDD.

Methods

The expression of ARRB1 in nucleus pulposus (NP) of rats with IVDD was assayed. Next, rat nucleus pulposus cells (NPCs) were infected with lentiviruses containing shArrb1 (LV-shArrb1) and overexpressing Arrb1 (LV-oeArrb1). The roles of Arrb1 in serum-deprived NPCs were investigated by measuring apoptosis, extracellular matrix degradation, and autophagic flux. For experiments in vivo, LV-oeArrb1 lentivirus was injected into the NP tissues of IVDD rats to evaluate the effects of Arrb1 overexpression on NP.

Results

In the NP tissues of IVDD rats, ARRB1 and cleaved caspase-3 expression increased, and the ratio of LC3II/LC3I protein expression was upregulated. Arrb1 knockdown aggravated extracellular matrix degradation, cellular apoptosis, and impairment of autophagic flux in rat NPCs under serum-deprived conditions, whereas Arrb1 overexpression significantly reversed these effects. ARRB1 interacted with Beclin 1, and Arrb1 knockdown suppressed the formation of the Beclin1-PIK3C3 core complex. The autophagy inhibitor 3-methyladenine (3-MA) offset the protective effects of Arrb1 overexpression in serum-deprived NPCs. Furthermore, Arrb1 overexpression inhibited apoptosis and extracellular matrix degradation, promoted autophagy in NP, and delayed the development of IVDD in rats.

Conclusion

ARRB1 prevents extracellular matrix degradation and apoptosis of NPCs by upregulating autophagy and ameliorating IVDD progression, presenting an innovative strategy for the treatment of IVDD.

FeS clusters are prosthetic groups present in all organisms. Proteins with FeS centers are involved in most cellular processes. ISC and SUF are machineries necessary for the formation and insertion of FeS in proteins. Recently, a phylogenetic analysis on more than 10,000 genomes of prokaryotes have uncovered two new systems, MIS and SMS, which were proposed to be ancestral to ISC and SUF. SMS is composed of SmsBC, two homologs of SufBC(D), the scaffolding complex of SUF. In this review, we will specifically focus on the current knowledge of the SUF system and on the new perspectives given by the recent discovery of its ancestor, the SMS system.

Background

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a bladder syndrome of unknown etiology. Reactive oxygen species (ROS) plays a major role in ferroptosis and bladder dysfunction of IC/BPS, while the role of ferroptosis in IC/BPS progression is still unclear. This study aims to investigate the role and mechanism of ROS-induced ferroptosis in IC/BPS using cell and rat model.

Methods

We collected IC/BPS patient bladder tissue samples and established a LPS-induced IC/BPS rat model (LRM). The level of oxidative stress and ferroptosis in IC/BPS patients and LRM rats was analyzed. Function and regulatory mechanism of ferroptosis in IC/BPS were explored by in vitro and in vivo experiments.

Results

The patients with IC/BPS showed mast cells and inflammatory cells infiltration in bladder epithelial tissues. Expression of NRF2 was up-regulated, and GPX4 was decreased in IC/BPS patients compared with normal tissues. IC model cells underwent oxidative stress, which induced ferroptosis. These above results were validated in LRM rat models, and inhibition of ferroptosis ameliorated bladder dysfunction in LRM rats. Wnt/β-catenin signaling was deactivated in IC/BPS patients and animals, and activation of Wnt/β-catenin signaling reduced cellular free radical production, thereby inhibited ferroptosis in IC model cells. Mechanistically, the Wnt/β-catenin signaling pathway inhibited oxidative stress-induced ferroptosis by down-regulating NF-κB, thus contributing to recover IC/BPS both in vitro and in vivo.

Conclusions

We demonstrate for the first time that oxidative stress-induced ferroptosis plays an important role in the pathology of IC/BPS. Mechanistically, the Wnt/β-catenin signaling suppressed oxidative stress-induced ferroptosis by down-regulating NF-κB to improve bladder injury in IC/BPS.

Background

Metabolic-associated fatty liver disease (MAFLD) is a leading cause of chronic liver disease worldwide. Autophagy plays a pivotal role in lipid metabolism; however, the mechanism underlying the reduced autophagic activity in MAFLD remains elusive.

Methods

Autophagy was monitored by TUNEL assay and immunofluorescence staining of LC3. The expression of autophagy-related proteins, PPARα, HDAC2, and HRD1 was detected by Western blot. The association between HDAC2 and PPARα promoter was assessed by chromatin immunoprecipitation (ChIP) and dual-luciferase assays, and the HRD1-mediated ubiquitin-proteasomal degradation of HDAC2 was detected by co-immunoprecipitation (co-IP). The in vitro findings were validated in a hypoxia-induced MAFLD mouse model. Histological changes, fibrosis, and apoptosis in liver tissues were detected by hematoxylin and eosin staining, Masson's trichrome staining, and TUNEL assay. The immunoreactivities of key molecules were examined by IHC analysis.

Results

Hypoxia-suppressed autophagy in hepatocytes. Hypoxic exposure downregulated HRD1 and PPARα, while upregulating HDAC2 in hepatocytes. Overexpression of PPARα promoted hepatic autophagy, while knocking down HDAC2 or overexpressing HRD1 reduced hypoxia-suppressed autophagy in hepatocytes. Mechanistically, HDAC2 acted as a transcriptional repressor of PPARα, and HRD1 mediated the degradation of HDAC2 through the ubiquitin-proteasome pathway. Functional studies further showed that hypoxia-suppressed hepatic autophagy via the HRD1/HDAC2/PPARα axis in vitro and in vivo.

Conclusion

HRD1-mediated ubiquitination of HDAC2 regulates PPARα-mediated autophagy and ameliorates hypoxia-induced MAFLD.

Akkermansia muciniphila (A. muciniphila), a probiotic, has been linked to macrophage phenotypic polarization in different diseases. However, the role and mechanisms of A. muciniphila in regulating macrophage during ulcerative colitis (UC) are not clear. This research aimed to examine the impact of A. muciniphila on dextran sulfate sodium (DSS)-induced acute colitis and elucidate the underlying mechanism related to macrophage phenotypic polarization. A. muciniphila inhibited weight loss, increased disease activity index, and ameliorated inflammatory injury in colonic tissues in mice induced with DSS. Furthermore, A. muciniphila reduced macrophage M1 polarization and ameliorated epithelial barrier damage in colonic tissues of DSS-induced mice through inhibition of histone deacetylase 5 (HDAC5). In contrast, the effect of A. muciniphila was compromised by HDAC5 overexpression. HDAC5 deacetylated H3K9ac modification of the disabled homolog 2 (DAB2) promoter, which led to repressed DAB2 expression. DAB2 overexpression blocked HDAC5-induced pro-inflammatory polarization of macrophages, whereas knockdown of DAB2 resulted in the loss of effects of A. muciniphila against colonic injury in DSS-induced mice. Taken together, A. muciniphila-induced loss of HDAC5 hampered the deacetylation of DAB2 and enhanced the expression of DAB2. Our findings propose that A. muciniphila may be a possible probiotic agent for alleviating DSS-induced acute colitis.

Preserving a functional mitochondrial network is crucial for cellular well-being, considering the pivotal role of mitochondria in ensuring cellular survival, especially under stressful conditions. Mitophagy, the selective removal of damaged mitochondria through autophagy, plays a pivotal role in preserving cellular homeostasis by preventing the production of harmful reactive oxygen species from dysfunctional mitochondria. While the involvement of mitophagy in neurodegenerative diseases has been thoroughly investigated, it is becoming increasingly evident that mitophagy plays a significant role in cancer biology. Perturbations in mitophagy pathways lead to suboptimal mitochondrial quality control, catalyzing various aspects of carcinogenesis, including establishing metabolic plasticity, stemness, metabolic reconfiguration of cancer-associated fibroblasts, and immunomodulation. While mitophagy performs a delicate balancing act at the intersection of cell survival and cell death, mounting evidence indicates that, particularly in the context of stress responses induced by cancer therapy, it predominantly promotes cell survival. Here, we showcase an overview of the current understanding of the role of mitophagy in cancer biology and its potential as a target for cancer therapy. Gaining a more comprehensive insight into the interaction between cancer therapy and mitophagy has the potential to reveal novel targets and pathways, paving the way for enhanced treatment strategies for therapy-resistant tumors in the near future.