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BMC Plant Biology Jun 2024Plant heterotrimeric G proteins respond to various environmental stresses, including high salinity. It is known that Gβ subunit AGB1 functions in maintaining local and...
BACKGROUND
Plant heterotrimeric G proteins respond to various environmental stresses, including high salinity. It is known that Gβ subunit AGB1 functions in maintaining local and systemic Na/K homeostasis to accommodate ionic toxicity under salt stress. However, whether AGB1 contributes to regulating gene expression for seedling's survival under high salinity remains unclear.
RESULTS
We showed that AGB1-Venus localized to nuclei when facing excessive salt, and the induction of a set of bZIP17-dependent salt stress-responsive genes was reduced in the agb1 mutant. We confirmed both genetic and physical interactions of AGB1 and bZIP17 in plant salinity response by comparing salt responses in the single and double mutants of agb1 and bzip17 and by BiFC assay, respectively. In addition, we show that AGB1 depletion decreases nuclei-localization of transgenic mRFP-bZIP17 under salt stress, as shown in s1p s2p double mutant in the Agrobacteria-mediated transient mRFP-bZIP17 expression in young seedlings.
CONCLUSIONS
Our results indicate that AGB1 functions in S1P and/or S2P-mediated proteolytic processing of bZIP17 under salt stress to regulate the induction of salinity-responsive gene expression.
Topics: Arabidopsis; Arabidopsis Proteins; GTP-Binding Protein beta Subunits; Basic-Leucine Zipper Transcription Factors; Unfolded Protein Response; Salinity; Salt Stress; Gene Expression Regulation, Plant; Seedlings
PubMed: 38902609
DOI: 10.1186/s12870-024-05296-x -
Scientific Reports Jun 2024Treatment of advanced triple-negative breast cancer (TNBC) is a great challenge in clinical practice. The immune checkpoints are a category of immunosuppressive...
Treatment of advanced triple-negative breast cancer (TNBC) is a great challenge in clinical practice. The immune checkpoints are a category of immunosuppressive molecules that cancer could hijack and impede anti-tumor immunity. Targeting immune checkpoints, such as anti-programmed cell death 1 (PD-1) therapy, is a promising therapeutic strategy in TNBC. The efficacy and safety of PD-1 monoclonal antibody (mAb) with chemotherapy have been validated in TNBC patients. However, the precise mechanisms underlying the synergistic effect of chemotherapy and anti-PD-1 therapy have not been elucidated, causing the TNBC patients that might benefit from this combination regimen not to be well selected. In the present work, we found that IL-23, an immunological cytokine, is significantly upregulated after chemotherapy in TNBC cells and plays a vital role in enhancing the anti-tumor immune response of cytotoxic T cells (CTLs), especially in combination with PD-1 mAb. In addition, the combination of IL-23 and PD-1 mAb could synergistically inhibit the expression of Phosphoinositide-3-Kinase Regulatory Subunit 1 (PIK3R1), which is a regulatory subunit of PI3K and inhibit p110 activity, and promote phosphorylation of AKT in TNBC-specific CTLs. Our findings might provide a molecular marker that could be used to predict the effects of combination chemotherapy therapy and PD-1 mAb in TNBC.
Topics: Humans; Proto-Oncogene Proteins c-akt; Triple Negative Breast Neoplasms; Signal Transduction; Phosphatidylinositol 3-Kinases; Programmed Cell Death 1 Receptor; Cell Line, Tumor; Female; T-Lymphocytes, Cytotoxic; Interleukin-23 Subunit p19; Animals; Mice; Antibodies, Monoclonal
PubMed: 38902343
DOI: 10.1038/s41598-024-65129-7 -
Nature Communications Jun 2024During pulmonary mucormycosis, inhaled sporangiospores adhere to, germinate, and invade airway epithelial cells to establish infection. We provide evidence that HIF1α...
During pulmonary mucormycosis, inhaled sporangiospores adhere to, germinate, and invade airway epithelial cells to establish infection. We provide evidence that HIF1α plays dual roles in airway epithelial cells during Mucorales infection. We observed an increase in HIF1α protein accumulation and increased expression of many known HIF1α-responsive genes during in vitro infection, indicating that HIF1α signaling is activated by Mucorales infection. Inhibition of HIF1α signaling led to a substantial decrease in the ability of R. delemar to invade cultured airway epithelial cells. Transcriptome analysis revealed that R. delemar infection induces the expression of many pro-inflammatory genes whose expression was significantly reduced by HIF1α inhibition. Importantly, pharmacological inhibition of HIF1α increased survival in a mouse model of pulmonary mucormycosis without reducing fungal burden. These results suggest that HIF1α plays two opposing roles during mucormycosis: one that facilitates the ability of Mucorales to invade the host cells and one that facilitates the ability of the host to mount an innate immune response.
Topics: Mucormycosis; Animals; Hypoxia-Inducible Factor 1, alpha Subunit; Mucorales; Humans; Epithelial Cells; Mice; Signal Transduction; Mice, Inbred C57BL; Disease Models, Animal; Lung; Female; Gene Expression Profiling
PubMed: 38902255
DOI: 10.1038/s41467-024-49637-8 -
ENeuro Jun 2024Formation and retrieval of remote contextual memory depends on cortical engram neurons that are defined during learning. Manipulation of astrocytic G and G associated...
Formation and retrieval of remote contextual memory depends on cortical engram neurons that are defined during learning. Manipulation of astrocytic G and G associated G-protein coupled receptor (GPCR) signaling has been shown to affect memory processing, but little is known about the role of cortical astrocytic G-GPCR signaling in remote memory acquisition and the functioning of cortical engram neurons. We assessed this by chemogenetic manipulation of astrocytes in the medial prefrontal cortex (mPFC) of male mice, during either encoding or consolidation of a contextual fear memory, while simultaneously labeling cortical engram neurons. We found that stimulation of astrocytic G signaling during memory encoding and consolidation did not alter remote memory expression. In line with this, the size of the mPFC engram population and the recall-induced reactivation of these neurons was unaffected. Hence, our data indicate that activation of G-GPCR signaling in cortical astrocytes is not sufficient to alter memory performance and functioning of cortical engram neurons.
Topics: Animals; Astrocytes; Male; Prefrontal Cortex; Signal Transduction; Neurons; Fear; Mice, Inbred C57BL; GTP-Binding Protein alpha Subunits, Gs; Mice; Memory; Memory, Long-Term
PubMed: 38902023
DOI: 10.1523/ENEURO.0056-24.2024 -
PLoS Pathogens Jun 2024Coronavirus (CoV) nonstructural protein 1 (nsp1) is considered a pathogenic factor due to its ability to inhibit host antiviral responses by inducing general shutoff of...
Coronavirus (CoV) nonstructural protein 1 (nsp1) is considered a pathogenic factor due to its ability to inhibit host antiviral responses by inducing general shutoff of host protein synthesis. Nsp1 is expressed by α- and β-CoVs, but its functions and strategies to induce host shutoff are not fully elucidated. We compared the nsp1s from two β-CoVs (SARS-CoV and SARS-CoV-2) and two α-CoVs (NL63 and 229E) and found that NL63 nsp1 has the strongest shutoff activity. Unlike SARS-CoV nsp1s, which bind to 40S ribosomes and block translation of cellular mRNA, NL63 nsp1 did not inhibit translation of mRNAs transfected into cells. Instead, NL63 nsp1 localized to the nucleus and specifically inhibited transcription of genes under an RNA polymerase II (RNAPII) promoter. Further analysis revealed that NL63 nsp1 induces degradation of the largest subunit of RNAPII, Rpb1. This degradation was detected regardless of the phosphorylation state of Rpb1 and was blocked by the proteasome inhibitor MG132. We also found that Rpb1 was ubiquitinated in NL63-infected cells, and inhibition of ubiquitination by a ubiquitin activating enzyme inhibitor (TAK243) prevented degradation of Rpb1 in virus-infected cells. These data reveal an unrecognized strategy of host shutoff by human α-CoV NL63: targeting host transcription by inducing Rpb1 degradation to prevent host protein expression. Our study indicates that viruses within the same family can use completely distinct mechanisms to regulate host antiviral responses.
PubMed: 38900816
DOI: 10.1371/journal.ppat.1012329 -
Oncotarget Jun 2024
Topics: Humans; Signal Transduction; Proto-Oncogene Proteins c-akt; Muscle, Smooth, Vascular; Phenotype; Aorta; Hypoxia-Inducible Factor 1, alpha Subunit; Phosphatidylinositol 3-Kinases; Myocytes, Smooth Muscle
PubMed: 38900608
DOI: 10.18632/oncotarget.28575 -
Journal of Cancer Research and Clinical... Jun 2024Targeted therapies have markedly improved the prognosis of lung cancer patients; nevertheless, challenges persist, including limited beneficiary populations and the...
PURPOSE
Targeted therapies have markedly improved the prognosis of lung cancer patients; nevertheless, challenges persist, including limited beneficiary populations and the emergence of drug resistance. This study investigates the molecular mechanisms of mutant TP53 in lung cancer, aiming to contribute to novel strategies for targeted therapy.
METHODS
The TCGA database was employed to delineate the mutational landscape of TP53 in lung cancer patients. Differential gene expression between TP53-mutant and wild-type patients was analyzed, followed by functional enrichment. DSG3 protein expression in lung cancer patients was assessed using IHC, and its impact on prognosis was analyzed in the TCGA database. The influence of TP53 on the downstream gene DSG3 was investigated using qPCR, ChIP-qPCR, and luciferase reporter gene assays. Protein enrichment in the DSG3 promoter region was examined through IP-MS, and the regulatory role of the HIF1-α/TP53 complex on DSG3 was explored using Co-IP, luciferase assays, and ChIP-qPCR. Molecular interactions between TP53 (R273H) and HIF1-α were detected through immunoprecipitation and molecular docking. The effects and mechanisms of DSG3 on lung cancer phenotypes were assessed through WB, transwell, and wound healing assays.
RESULTS
TP53 mutations were present in 47.44% of patients, predominantly as missense mutations. DSG3 exhibited high expression in TP53-mutant lung cancer patients, and this elevated expression correlated with a poorer prognosis. TP53 interference led to a reduction in DSG3 mRNA expression, with TP53 mutant P53 enriching at the P2 site of the DSG3 promoter region, a recruitment facilitated by HIF1-α. The DBD region of TP53 (R273H) demonstrated interaction with HIF1-α. DSG3, activated through Ezrin phosphorylation, played a role in promoting invasion and metastasis.
CONCLUSIONS
Mutant TP53 facilitates lung cancer cell invasion by modulating desmoglein 3.
Topics: Humans; Lung Neoplasms; Tumor Suppressor Protein p53; Mutation; Neoplasm Invasiveness; Desmoglein 3; Female; Prognosis; Male; Gene Expression Regulation, Neoplastic; Cell Line, Tumor; Middle Aged; Hypoxia-Inducible Factor 1, alpha Subunit
PubMed: 38900156
DOI: 10.1007/s00432-024-05778-3 -
MBio Jun 2024Inositol pyrophosphates are signaling molecules that regulate cellular phosphate homeostasis in eukaryal taxa. In fission yeast, where the phosphate regulon (comprising...
Inositol pyrophosphates are signaling molecules that regulate cellular phosphate homeostasis in eukaryal taxa. In fission yeast, where the phosphate regulon (comprising phosphate acquisition genes , , and ) is repressed under phosphate-replete conditions by lncRNA-mediated transcriptional interference, mutations of inositol pyrophosphatases that increase IP levels derepress the regulon by eliciting precocious termination of lncRNA transcription. Asp1 pyrophosphatase mutations resulting in too much IP are cytotoxic in YES medium owing to overexpression of glycerophosphodiester transporter Tgp1. IP toxicosis is ameliorated by mutations in cleavage/polyadenylation and termination factors, perturbations of the Pol2 CTD code, and mutations in SPX domain proteins that act as inositol pyrophosphate sensors. Here, we show that IP toxicity is alleviated by deletion of , the gene encoding the ATPase subunit of the SWI/SNF chromatin remodeling complex, by an ATPase-inactivating () allele, and by deletion of the gene encoding SWI/SNF subunit Sol1. Deletion of hyper-repressed expression in phosphate-replete cells; suppressed the derepression elicited by mutations in Pol2 CTD, termination factor Seb1, Asp1 pyrophosphatase, and 14-3-3 protein Rad24 (that favor precocious lncRNA termination); and delayed induction during phosphate starvation. RNA analysis and lack of mutational synergies suggest that Snf22 is not impacting 3'-processing/termination. Using reporter assays, we find that Snf22 is important for the activity of the and promoters, but not for the promoters that drive the synthesis of the -repressive lncRNAs. Transcription profiling of ∆ and () cells identified an additional set of 66 protein-coding genes that were downregulated in both mutants.IMPORTANCERepression of the fission yeast genes , , and by lncRNA-mediated interference is sensitive to inositol pyrophosphate dynamics. Cytotoxic alleles derepress the genes via the action of IP as an agonist of precocious lncRNA 3'-processing/termination. IP toxicosis is alleviated by mutations of the Pol2 CTD and the 3'-processing/termination machinery that dampen the impact of toxic IP levels on termination. In this study, a forward genetic screen revealed that IP toxicity is suppressed by mutations of the Snf22 and Sol1 subunits of the SWI/SNF chromatin remodeling complex. Genetic and biochemical evidence indicates that the SWI/SNF is not affecting 3'-processing/termination or lncRNA promoter activity. Rather, SWI/SNF is critical for firing the mRNA promoters. Our results implicate the ATP-dependent nucleosome remodeling activity of SWI/SNF as necessary to ensure full access of -activating transcription factor Pho7 to its binding sites in the mRNA promoters.
PubMed: 38899862
DOI: 10.1128/mbio.01252-24 -
Journal of Cellular and Molecular... Jun 2024Hypoxia poses a significant challenge to the effectiveness of radiotherapy in head and neck squamous cell carcinoma (HNSCC) patients, and it is imperative to discover...
Hypoxia poses a significant challenge to the effectiveness of radiotherapy in head and neck squamous cell carcinoma (HNSCC) patients, and it is imperative to discover novel approaches to overcome this. In this study, we investigated the underlying mechanisms contributing to x-ray radioresistance in HPV-negative HNSCC cells under mild hypoxic conditions (1% oxygen) and explored the potential for autophagy modulation as a promising therapeutic strategy. Our findings show that HNSCC cells exposed to mild hypoxic conditions exhibit increased radioresistance, which is largely mediated by the hypoxia-inducible factor (HIF) pathway. We demonstrate that siRNA knockdown of HIF-1α and HIF-1β leads to increased radiosensitivity in HNSCC cells under hypoxia. Hypoxia-induced radioresistance was not attributed to differences in DNA double strand break repair kinetics, as these remain largely unchanged under normoxic and hypoxic conditions. Rather, we identify autophagy as a critical protective mechanism in HNSCC cells following irradiation under mild hypoxia conditions. Targeting key autophagy genes, such as BECLIN1 and BNIP3/3L, using siRNA sensitizes these cells to irradiation. Whilst autophagy's role in hypoxic radioresistance remains controversial, this study highlights the importance of autophagy modulation as a potential therapeutic approach to enhance the effectiveness of radiotherapy in HNSCC.
Topics: Humans; Autophagy; Radiation Tolerance; Cell Line, Tumor; Squamous Cell Carcinoma of Head and Neck; Cell Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Beclin-1; Head and Neck Neoplasms; Membrane Proteins; DNA Repair; RNA, Small Interfering; Proto-Oncogene Proteins; X-Rays; DNA Breaks, Double-Stranded; Tumor Suppressor Proteins
PubMed: 38899556
DOI: 10.1111/jcmm.18482 -
World Journal of Gastroenterology Jun 2024Pancreatic cancer (PC) is associated with some of the worst prognoses of all major cancers. Thymoquinone (TQ) has a long history in traditional medical practice and is...
BACKGROUND
Pancreatic cancer (PC) is associated with some of the worst prognoses of all major cancers. Thymoquinone (TQ) has a long history in traditional medical practice and is known for its anti-cancer, anti-inflammatory, anti-fibrosis and antioxidant pharmacological activities. Recent studies on hypoxia-inducible factor-1α (HIF-1α) and PC have shown that HIF-1α affects the occurrence and development of PC in many aspects. In addition, TQ could inhibit the development of renal cancer by decreasing the expression of HIF-1α. Therefore, we speculate whether TQ affects HIF-1α expression in PC cells and explore the mechanism.
AIM
To elucidate the effect of TQ in PC cells and the regulatory mechanism of HIF-1α expression.
METHODS
Cell counting kit-8 assay, Transwell assay and flow cytometry were performed to detect the effects of TQ on the proliferative activity, migration and invasion ability and apoptosis of PANC-1 cells and normal pancreatic duct epithelial (hTERT-HPNE) cells. Quantitative real-time polymerase chain reaction and western blot assay were performed to detect the expression of HIF-1α mRNA and protein in PC cells. The effects of TQ on the HIF-1α protein initial expression pathway and ubiquitination degradation in PANC-1 cells were examined by western blot assay and co-immunoprecipitation.
RESULTS
TQ significantly inhibited proliferative activity, migration, and invasion ability and promoted apoptosis of PANC-1 cells; however, no significant effects on hTERT-HPNE cells were observed. TQ significantly reduced the mRNA and protein expression levels of HIF-1α in PANC-1, AsPC-1, and BxPC-3 cells. TQ significantly inhibited the expression of the HIF-1α initial expression pathway (PI3K/AKT/mTOR) related proteins, and promoted the ubiquitination degradation of the HIF-1α protein in PANC-1 cells. TQ had no effect on the hydroxylation and von Hippel Lindau protein mediated ubiquitination degradation of the HIF-1α protein but affected the stability of the HIF-1α protein by inhibiting the interaction between HIF-1α and HSP90, thus promoting its ubiquitination degradation.
CONCLUSION
The regulatory mechanism of TQ on HIF-1α protein expression in PC cells was mainly to promote the ubiquitination degradation of the HIF-1α protein by inhibiting the interaction between HIF-1α and HSP90; Secondly, TQ reduced the initial expression of HIF-1α protein by inhibiting the PI3K/AKT/mTOR pathway.
Topics: Benzoquinones; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; HSP90 Heat-Shock Proteins; Pancreatic Neoplasms; Proto-Oncogene Proteins c-akt; TOR Serine-Threonine Kinases; Cell Line, Tumor; Signal Transduction; Cell Proliferation; Apoptosis; Cell Movement; Phosphatidylinositol 3-Kinases; Gene Expression Regulation, Neoplastic; Neoplasm Invasiveness
PubMed: 38899332
DOI: 10.3748/wjg.v30.i21.2793