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PloS One 2024Prenatal alcohol exposure (PAE) causes cognitive impairment and a distinctive craniofacial dysmorphology, due in part to apoptotic losses of the pluripotent cranial...
Prenatal alcohol exposure (PAE) causes cognitive impairment and a distinctive craniofacial dysmorphology, due in part to apoptotic losses of the pluripotent cranial neural crest cells (CNCs) that form facial bones and cartilage. We previously reported that PAE rapidly represses expression of >70 ribosomal proteins (padj = 10-E47). Ribosome dysbiogenesis causes nucleolar stress and activates p53-MDM2-mediated apoptosis. Using primary avian CNCs and the murine CNC line O9-1, we tested whether nucleolar stress and p53-MDM2 signaling mediates this apoptosis. We further tested whether haploinsufficiency in genes that govern ribosome biogenesis, using a blocking morpholino approach, synergizes with alcohol to worsen craniofacial outcomes in a zebrafish model. In both avian and murine CNCs, pharmacologically relevant alcohol exposure (20mM, 2hr) causes the dissolution of nucleolar structures and the loss of rRNA synthesis; this nucleolar stress persisted for 18-24hr. This was followed by reduced proliferation, stabilization of nuclear p53, and apoptosis that was prevented by overexpression of MDM2 or dominant-negative p53. In zebrafish embryos, low-dose alcohol or morpholinos directed against ribosomal proteins Rpl5a, Rpl11, and Rps3a, the Tcof homolog Nolc1, or mdm2 separately caused modest craniofacial malformations, whereas these blocking morpholinos synergized with low-dose alcohol to reduce and even eliminate facial elements. Similar results were obtained using a small molecule inhibitor of RNA Polymerase 1, CX5461, whereas p53-blocking morpholinos normalized craniofacial outcomes under high-dose alcohol. Transcriptome analysis affirmed that alcohol suppressed the expression of >150 genes essential for ribosome biogenesis. We conclude that alcohol causes the apoptosis of CNCs, at least in part, by suppressing ribosome biogenesis and invoking a nucleolar stress that initiates their p53-MDM2 mediated apoptosis. We further note that the facial deficits that typify PAE and some ribosomopathies share features including reduced philtrum, upper lip, and epicanthal distance, suggesting the facial deficits of PAE represent, in part, a ribosomopathy.
Topics: Animals; Neural Crest; Zebrafish; Ribosomes; Ethanol; Tumor Suppressor Protein p53; Apoptosis; Mice; Proto-Oncogene Proteins c-mdm2; Cell Nucleolus; Ribosomal Proteins; Skull; Zebrafish Proteins
PubMed: 38941348
DOI: 10.1371/journal.pone.0304557 -
The Journal of Clinical Investigation Jun 2024Clear cell renal cell carcinoma (ccRCC) is an aggressive cancer driven by VHL loss and aberrant HIF-2α signaling. Identifying means to regulate HIF-2α thus has...
Clear cell renal cell carcinoma (ccRCC) is an aggressive cancer driven by VHL loss and aberrant HIF-2α signaling. Identifying means to regulate HIF-2α thus has potential therapeutic benefit. Acetyl-CoA synthetase 2 (ACSS2) converts acetate to acetyl-CoA and is associated with poor patient prognosis in ccRCC. Here we tested the effects of ACSS2 on HIF-2α and cancer cell metabolism and growth in ccRCC models and clinical samples. ACSS2 inhibition reduced HIF-2α levels and suppressed ccRCC cell line growth in vitro, in vivo, and in cultures of primary ccRCC patient tumors. This treatment reduced glycolytic signaling, cholesterol metabolism, and mitochondrial integrity, all of which are consistent with loss of HIF-2α. Mechanistically, ACSS2 inhibition decreased chromatin accessibility and HIF-2α expression and stability. While HIF-2α protein levels are widely regulated through pVHL-dependent proteolytic degradation, we identify a potential pVHL-independent pathway of degradation via the E3 ligase MUL1. We show that MUL1 can directly interact with HIF-2α and that overexpression of MUL1 decreased HIF-2α levels in a manner partially dependent on ACSS2. These findings identify multiple mechanisms to regulate HIF-2α stability and ACSS2 inhibition as a strategy to complement HIF-2α-targeted therapies and deplete pathogenically stabilized HIF-2α.
Topics: Carcinoma, Renal Cell; Humans; Basic Helix-Loop-Helix Transcription Factors; Kidney Neoplasms; Cell Line, Tumor; Acetate-CoA Ligase; Signal Transduction; Animals; Mice; Gene Expression Regulation, Neoplastic; Von Hippel-Lindau Tumor Suppressor Protein; Ubiquitin-Protein Ligases; Neoplasm Proteins
PubMed: 38941296
DOI: 10.1172/JCI164249 -
Metabolomics : Official Journal of the... Jun 2024Exploring metabolic changes within host E. coli through an untargeted metabolomic study of T7L variants overexpression to optimize engineered endolysins for...
INTRODUCTION
Exploring metabolic changes within host E. coli through an untargeted metabolomic study of T7L variants overexpression to optimize engineered endolysins for clinical/therapeutic use.
AIM AND OBJECTIVE
This study aims to assess the impact of overexpressing T7L variants on the metabolic profiles of E. coli. The two variants considered include T7L-H37A, which has enhanced lytic activity compared to its wild-type protein, and T7L-H48K, a dead mutant with no significant activity.
METHODS
H NMR-based metabolomics was employed to compare the metabolic profiles of E. coli cells overexpressing T7L wild-type protein and its variants.
RESULTS
Overexpression of the T7L wild-type (T7L-WT) protein and its variants (T7L-H48K and T7L-H37A) was compared to RNAP overexpression in E. coli cells using H NMR-based metabolomics, analyzing a total of 75 annotated metabolites, including organic acids, amino acids, sugars, and nucleic acids. The results showed distinct clustering patterns for the two T7L variant groups compared with the WT, in which the dead mutant (H48K) group showed clustering close to that of RNAP. Pathway impact analysis revealed different effects of T7L variants on E. coli metabolic profiles, with T7L-H48K showing minimal alterations in energy and amino acid pathways linked to osmotic stress compared to noticeable alterations in these pathways for both T7L-H37A and T7L-WT.
CONCLUSIONS
This study uncovered distinct metabolic fingerprints when comparing the overexpression of active and inactive mutants of T7L lytic enzymes in E. coli cells. These findings could contribute to the optimization and enhancement of suitable endolysins as potential alternatives to antibiotics.
Topics: Escherichia coli; Metabolome; Metabolomics; Viral Proteins; Bacteriophage T7; Mutation; DNA-Directed RNA Polymerases
PubMed: 38941046
DOI: 10.1007/s11306-024-02133-y -
BdRCN4, a Brachypodium distachyon TFL1 homologue, is involved in regulation of apical meristem fate.Plant Molecular Biology Jun 2024In higher plants, the shift from vegetative to reproductive development is governed by complex interplay of internal and external signals. TERMINALFLOWER1 (TFL1) plays a...
In higher plants, the shift from vegetative to reproductive development is governed by complex interplay of internal and external signals. TERMINALFLOWER1 (TFL1) plays a crucial role in the regulation of flowering time and inflorescence architecture in Arabidopsis thaliana. This study aimed to explore the function of BdRCN4, a homolog of TFL1 in Brachypodium distachyon, through functional analyses in mutant and transgenic plants. The results revealed that overexpression of BdRCN4 in B. distachyon leads to an extended vegetative phase and reduced production of spikelets. Similar results were found in A. thaliana, where constitutive expression of BdRCN4 promoted a delay in flowering time, followed by the development of hypervegetative shoots, with no flowers or siliques produced. Our results suggest that BdRCN4 acts as a flowering repressor analogous to TFL1, negatively regulating AP1, but no LFY expression. To further validate this hypothesis, a 35S::LFY-GR co-transformation approach on 35::BdRCN4 lines was performed. Remarkably, AP1 expression levels and flower formation were restored to normal in co-transformed plants when treated with dexamethasone. Although further molecular studies will be necessary, the evidence in B. distachyon support the idea that a balance between LFY and BdRCN4/TFL1 seems to be essential for activating AP1 expression and initiating floral organ identity gene expression. This study also demonstrates interesting conservation through the molecular pathways that regulate flowering meristem transition and identity across the evolution of monocot and dicot plants.
Topics: Brachypodium; Meristem; Gene Expression Regulation, Plant; Plant Proteins; Flowers; Plants, Genetically Modified; Arabidopsis; Arabidopsis Proteins
PubMed: 38940986
DOI: 10.1007/s11103-024-01467-4 -
Alternative Therapies in Health and... Jun 2024Osteoporosis (OP) is a chronic skeletal disorder characterized by low bone mass and microarchitectural deterioration of bone tissue, resulting in increased bone...
Study on the Mechanism of Xianling Gubao Capsule Regulating Runt-Related Transcription Factor 2 (RUNX2) and Promoting Osteoblast Differentiation by N6-Methyladenosine (m6A) Methyltransferase-Like 3 (METTL3).
BACKGROUND
Osteoporosis (OP) is a chronic skeletal disorder characterized by low bone mass and microarchitectural deterioration of bone tissue, resulting in increased bone fragility and a higher risk of fractures. It is a significant public health concern, particularly among postmenopausal women and older adults. The imbalance between bone formation and resorption is the fundamental cause of OP. Current clinical drugs for OP have limited efficacy and can cause side effects. Therefore, there is a need to explore alternative treatments and investigate their mechanisms to improve OP management. The Xianling Gubao capsule, a traditional Chinese medicine, is commonly used to treat OP by tonifying the kidney. However, the specific mechanism of action of the Xianling Gubao capsule in improving OP remains unclear, necessitating further research in this area.
METHODS
The N6-methyladenosine (m6A) content was evaluated by dot blot and m6A ribonucleic acid (RNA) methylation assay kit. The contents of methyltransferase-like 3 (METTL3), runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), and bone gamma-carboxyglutamate protein (BGLAP) were appraised by quantitative Reverse Transcription polymerase chain reaction (qRT-PCR) and western blot. The bilateral ovariectomy (OVX) method was used to establish an animal model of OP. OP bone marrow mesenchymal stem cells (OP-BMSCs) were extracted from mice in the OVX group by the whole bone marrow method. METTL3 overexpression and control vectors were transfected to OP-BMSCs using X-tremeGENE HP DNA Transfection Reagent. The ALP activity in OP-BMSCs was assessed by ALP staining. The calcium nodules in OP-BMSCs were detected by Alizarin Red S (ARS) assay. The Xianling Gubao capsule solution was employed to gavage mice, and the drug-containing serum was used to treat OP-BMSCs. Dot blot allows for the assessment of relative levels of m6A modification. The m6A RNA methylation assay kit is a specialized kit designed to quantitatively measure m6A levels in RNA samples. qRT-PCR allows for the measurement of mRNA levels of target genes. Western blot is used to detect and quantify specific proteins in a sample, and provides information about protein expression levels. OVX mimics the hormonal changes occurring in postmenopausal women and leads to bone loss and osteoporotic conditions in animals. This model allows for the investigation of the effects of the Xianling Gubao capsule on OP in a controlled experimental setting.
RESULTS
The m6A modification and METTL3, RUNX2, ALP, and BGLAP levels were reduced in bone samples of patients with OP and OVX mice compared with the corresponding control groups. Upregulated METTL3 enhanced the osteogenic ability of OP-BMSCs. METTL3 overexpression obviously increased m6A modification and METTL3, RUNX2, ALP, and BGLAP levels in OP-BMSCs. Xianling Gubao capsule treatment could weaken the impact of OP in mice by regulating the m6A modification and METTL3, RUNX2, ALP, and BGLAP levels. Serum containing Xianling Gubao capsule could enhance the osteogenic capability of OP-BMSCs and boost METTL3, RUNX2, ALP, and BGLAP levels. Treatment with the Xianling Gubao capsule shows promising effects in attenuating the impact of OP. The capsule is found to regulate m6A modification and increase the levels of METTL3, RUNX2, ALP, and BGLAP in OP-BMSCs. This indicates that the Xianling Gubao capsule may rescue the diminished osteogenic capability of OP-BMSCs by modulating METTL3. These findings suggest that the Xianling Gubao capsule has the potential to be an effective drug for the treatment of OP.
CONCLUSION
Taken together, the m6A modification and contents of osteogenic-related factors were reduced in OP. Upregulated METTL3 improved the osteogenic ability, m6A modification, and osteogenic-related factor abundances in OP-BMSCs. Xianling Gubao capsule rescued the diminished osteogenic capability of OP-BMSCs by modulating METTL3 and might serve as an effective drug for OP. The Xianling Gubao capsule, as a traditional Chinese medicine, could potentially complement existing therapeutic approaches for OP. By targeting the m6A modification pathway and promoting osteogenic differentiation, the capsule may help to expedite bone formation and repair, which are critical for managing OP and reducing the risk of fractures.
PubMed: 38940781
DOI: No ID Found -
Journal of Integrative Plant Biology Jun 2024Tiller angle is a key agricultural trait that establishes plant architecture, which in turn strongly affects grain yield by influencing planting density in rice. The...
Tiller angle is a key agricultural trait that establishes plant architecture, which in turn strongly affects grain yield by influencing planting density in rice. The shoot gravity response plays a crucial role in the regulation of tiller angle in rice, but the underlying molecular mechanism is largely unknown. Here, we report the identification of the BIG TILLER ANGLE2 (BTA2), which regulates tiller angle by controlling the shoot gravity response in rice. Loss-of-function mutation of BTA2 dramatically reduced auxin content and affected auxin distribution in rice shoot base, leading to impaired gravitropism and therefore a big tiller angle. BTA2 interacted with AUXIN RESPONSE FACTOR7 (ARF7) to modulate rice tiller angle through the gravity signaling pathway. The BTA2 protein was highly conserved during evolution. Sequence variation in the BTA2 promoter of indica cultivars harboring a less expressed BTA2 allele caused lower BTA2 expression in shoot base and thus wide tiller angle during rice domestication. Overexpression of BTA2 significantly increased grain yield in the elite rice cultivar Huanghuazhan under appropriate dense planting conditions. Our findings thus uncovered the BTA2-ARF7 module that regulates tiller angle by mediating the shoot gravity response. Our work offers a target for genetic manipulation of plant architecture and valuable information for crop improvement by producing the ideal plant type.
PubMed: 38940609
DOI: 10.1111/jipb.13726 -
Pathology International Jun 2024Exosomes from cancer cells function as carriers to spread or transport specific microRNAs (miRNAs) to distant sites to exert their effects, but the mechanism of exosomal...
Exosomes from cancer cells function as carriers to spread or transport specific microRNAs (miRNAs) to distant sites to exert their effects, but the mechanism of exosomal miRNA action in esophageal squamous cell carcinoma (ESCC) has not been fully explained. Therefore, in this study, we were interested in the impact of exosomal miR-196a-5p in ESCC progression. We found that miR-196a-5p was expressed enriched in clinical tissues, ESCC cells, and exosomes. Functionally, depletion of miR-196a-5p impeded ESCC cell growth, migration, and invasion, whereas overexpression of miR-196a-5p produced the opposite results. Moreover, enhancement of exosomal miR-196a-5p in recipient ESCC cells triggered more intense proliferation and migration. Mechanistically, we identified integral membrane protein 2B (ITM2B) as a direct target of miR-196a-5p. Silencing of ITM2B partially counteracted the inhibitory effect of miR-196a-5p inhibitors on the malignant phenotype of ESCC. Furthermore, in vivo, lower miR-196a-5p levels triggered by the introduction of antagomiR-196a-5p resulted in the generation of smaller volume and weight xenograft tumors. Thus, our results demonstrated novel mechanisms of exosomal and intracellular miR-196a-5p-mediated ESCC growth and migration and identify the interaction of miR-196a-5p with ITM2B. These works might provide new targets and basis for the development of clinical treatment options for ESCC.
PubMed: 38940569
DOI: 10.1111/pin.13459 -
MBio Jun 2024Merkel cell polyomavirus (MCPyV) is a double-stranded tumor virus that is the main causative agent of Merkel cell carcinoma (MCC). The MCPyV large T antigen (LT), an...
UNLABELLED
Merkel cell polyomavirus (MCPyV) is a double-stranded tumor virus that is the main causative agent of Merkel cell carcinoma (MCC). The MCPyV large T antigen (LT), an essential viral DNA replication protein, maintains viral persistence by interacting with host Skp1-Cullin 1-F-box (SCF) E3 ubiquitin ligase complexes, which subsequently induces LT's proteasomal degradation, restricting MCPyV DNA replication. SCF E3 ubiquitin ligases require their substrates to be phosphorylated to bind them, utilizing phosphorylated serine residues as docking sites. The MCPyV LT unique region (MUR) is highly phosphorylated and plays a role in multiple host protein interactions, including SCF E3 ubiquitin ligases. Therefore, this domain highly governs LT stability. Though much work has been conducted to identify host factors that restrict MCPyV LT protein expression, the kinase(s) that cooperates with the SCF E3 ligase remains unknown. Here, we demonstrate that casein kinase 1 alpha (CK1α) negatively regulates MCPyV LT stability and LT-mediated replication by modulating interactions with the SCF β-TrCP. Specifically, we show that numerous CK1 isoforms (α, δ, ε) localize in close proximity to MCPyV LT through proximity ligation assays (PLA) and CK1α overexpression mainly resulted in decreased MCPyV LT protein expression. Inhibition of CK1α using short hairpin RNA (shRNA) and treatment of a CK1α inhibitor or an mTOR inhibitor, TORKinib, resulted in decreased β-TrCP interaction with LT, increased LT expression, and enhanced MCPyV replication. The expression level of the gene transcripts is higher in MCPyV-positive MCC, suggesting a vital role of CK1α in limiting MCPyV replication required for establishing persistent infection.
IMPORTANCE
Merkel cell polyomavirus (MCPyV) large tumor antigen is a polyphosphoprotein and the phosphorylation event is required to modulate various functions of LT, including viral replication. Therefore, cellular kinase pathways are indispensable for governing MCPyV polyomavirus infection and life cycle in coordinating with the immunosuppression environment at disease onset. Understanding the regulation mechanisms of MCPyV replication by viral and cellular factors will guide proper prevention strategies with targeted inhibitors for MCPyV-associated Merkel cell carcinoma (MCC) patients, who currently lack therapies.
PubMed: 38940554
DOI: 10.1128/mbio.01117-24 -
Advanced Science (Weinheim,... Jun 2024Transmembrane protein 52B (TMEM52B), a newly identified tumor-related gene, has been reported to regulate various tumors, yet its role in nasopharyngeal carcinoma (NPC)...
Transmembrane protein 52B (TMEM52B), a newly identified tumor-related gene, has been reported to regulate various tumors, yet its role in nasopharyngeal carcinoma (NPC) remains unclear. Transcriptomic analysis of NPC cell lines reveals frequent overexpression of TMEM52B, and immunohistochemical results show that TMEM52B is associated with advanced tumor stage, recurrence, and decreased survival time. Depleting TMEM52B inhibits the proliferation, migration, invasion, and oncogenesis of NPC cells in vivo. TMEM52B encodes two isoforms, TMEM52B-P18 and TMEM52B-P20, differing in their N-terminals. While both isoforms exhibit similar pro-oncogenic roles and contribute to drug resistance in NPC, TMEM52B-P20 differentially promotes metastasis. This functional discrepancy may be attributed to their distinct subcellular localization; TMEM52B-P18 is confined to the cytoplasm, while TMEM52B-P20 is found both at the cell membrane and in the cytoplasm. Mechanistically, cytoplasmic TMEM52B enhances AKT phosphorylation by interacting with phosphoglycerate kinase 1 (PGK1), fostering NPC growth and metastasis. Meanwhile, membrane-localized TMEM52B-P20 promotes E-cadherin ubiquitination and degradation by facilitating its interaction with the E3 ubiquitin ligase NEDD4, further driving NPC metastasis. In conclusion, the TMEM52B-P18 and TMEM52B-P20 isoforms promote the metastasis of NPC cells through different mechanisms. Drugs targeting these TMEM52B isoforms may offer therapeutic benefits to cancer patients with varying degrees of metastasis.
PubMed: 38940427
DOI: 10.1002/advs.202402457 -
Histology and Histopathology Jun 2024Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumor. Among the S100 protein family members, the imbalance of S100 calcium-binding protein A2 (S100A2) was...
Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumor. Among the S100 protein family members, the imbalance of S100 calcium-binding protein A2 (S100A2) was related to the pathogenesis of several types of cancer, and S100A2 has been reported to be upregulated in the plasma of NPC patients; however, its specific role in NPC pathogenesis remains unclear. Thus, this study aims to determine the potential role of S100A2 in NPC to provide novel insights into NPC management. C666-1 and NPC/HK-1 cells were transfected with S100A2 silencing/overexpression (si/oe) constructs. For investigations, NPC/HK-1 cells were transfected with si/oe-S100A2 to induce tumor formation in nude mice. Cellular viability and apoptosis were assessed using the CCK8 assay, colony-forming assay, and flow cytometry. Glucose uptake and lactate production levels were quantified using biochemical assays. S100A2 expression was measured via RT-qPCR, Western blot, immunohistochemistry, and immunofluorescence were performed to determine the levels of S100A2, PI3K, AKT, p-PI3K, p-AKT, GLUT1, HK-2, LDHA, and ki-67 proteins. S100A2 expression levels were significantly higher in NPC cancer tissues than in adjacent tissues. Similarly, C666-1 and NPC/HK-1 cells exhibited increased S100A2 expression, and silencing S100A2 significantly inhibited NPC cell viability, proliferation, glucose uptake, and lactate production, and induced apoptosis and decreased the protein levels of GLUT1, LDHA, and HK2 in NPC cells. Conversely, S100A2 overexpression enhanced these characteristics in NPC cells but could be mitigated by the PI3K/AKT inhibitor (LY294002). Silencing S100A2 suppressed the tumor formation of NPC/HK-1 cells, while S100A2 overexpression promoted tumor formation and could be hindered by a GLUT1 inhibitor (WZB117). S100A2 is upregulated in cancer tissues of NPC patients and was found to promote proliferation, glycolysis, and tumor formation in NPC cells through its interaction with GLUT1.
PubMed: 38940398
DOI: 10.14670/HH-18-778