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World Journal of Gastroenterology May 2024Cell division cyclin 25C () is a protein that plays a critical role in the cell cycle, specifically in the transition from the G2 phase to the M phase. Recent research...
BACKGROUND
Cell division cyclin 25C () is a protein that plays a critical role in the cell cycle, specifically in the transition from the G2 phase to the M phase. Recent research has shown that could be a potential therapeutic target for cancers, particularly for hepatocellular carcinoma (HCC). However, the specific regulatory mechanisms underlying the role of in HCC tumorigenesis and development remain incompletely understood.
AIM
To explore the impact of on cell proliferation and apoptosis, as well as its regulatory mechanisms in HCC development.
METHODS
Hepa1-6 and B16 cells were transduced with a lentiviral vector containing shRNA interference sequences (LV- shRNA) to knock down . Subsequently, a xenograft mouse model was established by subcutaneously injecting transduced Hepa1-6 cells into mice to assess the effects of knockdown on HCC development . Cell proliferation and migration were evaluated using a Cell Counting Kit-8 cell proliferation assays and wound healing assays, respectively. The expression of endoplasmic reticulum (ER) stress-related molecules (glucose-regulated protein 78, X-box binding protein-1, and C/EBP homologous protein) was measured in both cells and subcutaneous xenografts using quantitative real-time PCR (qRT-PCR) and western blotting. Additionally, apoptosis was investigated using flow cytometry, qRT-PCR, and western blotting.
RESULTS
was stably suppressed in Hepa1-6 and B16 cells through LV- shRNA transduction. A xenograft model with knockdown was successfully established and that downregulation of expression significantly inhibited HCC growth in mice. knockdown not only inhibited cell proliferation and migration but also significantly increased the ER stress response, ultimately promoting ER stress-induced apoptosis in HCC cells.
CONCLUSION
The regulatory mechanism of in HCC development may involve the activation of ER stress and the ER stress-induced apoptosis signaling pathway.
Topics: Animals; Endoplasmic Reticulum Stress; Carcinoma, Hepatocellular; Cell Proliferation; cdc25 Phosphatases; Apoptosis; Liver Neoplasms; Cell Line, Tumor; Mice; Gene Knockdown Techniques; Cell Movement; Mice, Inbred C57BL; Humans; RNA, Small Interfering; Male; Gene Expression Regulation, Neoplastic; Xenograft Model Antitumor Assays; Carcinogenesis
PubMed: 38817663
DOI: 10.3748/wjg.v30.i19.2564 -
BMC Biology May 2024The innate immune system serves as the first line of host defense. Transforming growth factor-β-activated kinase 1 (TAK1) is a key regulator of innate immunity, cell...
BACKGROUND
The innate immune system serves as the first line of host defense. Transforming growth factor-β-activated kinase 1 (TAK1) is a key regulator of innate immunity, cell survival, and cellular homeostasis. Because of its importance in immunity, several pathogens have evolved to carry TAK1 inhibitors. In response, hosts have evolved to sense TAK1 inhibition and induce robust lytic cell death, PANoptosis, mediated by the RIPK1-PANoptosome. PANoptosis is a unique innate immune inflammatory lytic cell death pathway initiated by an innate immune sensor and driven by caspases and RIPKs. While PANoptosis can be beneficial to clear pathogens, excess activation is linked to pathology. Therefore, understanding the molecular mechanisms regulating TAK1 inhibitor (TAK1i)-induced PANoptosis is central to our understanding of RIPK1 in health and disease.
RESULTS
In this study, by analyzing results from a cell death-based CRISPR screen, we identified protein phosphatase 6 (PP6) holoenzyme components as regulators of TAK1i-induced PANoptosis. Loss of the PP6 enzymatic component, PPP6C, significantly reduced TAK1i-induced PANoptosis. Additionally, the PP6 regulatory subunits PPP6R1, PPP6R2, and PPP6R3 had redundant roles in regulating TAK1i-induced PANoptosis, and their combined depletion was required to block TAK1i-induced cell death. Mechanistically, PPP6C and its regulatory subunits promoted the pro-death S166 auto-phosphorylation of RIPK1 and led to a reduction in the pro-survival S321 phosphorylation.
CONCLUSIONS
Overall, our findings demonstrate a key requirement for the phosphatase PP6 complex in the activation of TAK1i-induced, RIPK1-dependent PANoptosis, suggesting this complex could be therapeutically targeted in inflammatory conditions.
Topics: Receptor-Interacting Protein Serine-Threonine Kinases; Humans; Phosphoprotein Phosphatases; MAP Kinase Kinase Kinases; Necroptosis; Immunity, Innate
PubMed: 38807188
DOI: 10.1186/s12915-024-01901-5 -
Open Biology May 2024The precise spatial and temporal control of histone phosphorylations is important for the ordered progression through the different phases of mitosis. The...
The precise spatial and temporal control of histone phosphorylations is important for the ordered progression through the different phases of mitosis. The phosphorylation of H2B at S6 (H2B S6ph), which is crucial for chromosome segregation, reaches its maximum level during metaphase and is limited to the inner centromere. We discovered that the temporal and spatial regulation of this modification, as well as its intensity, are governed by the scaffold protein RepoMan and its associated catalytically active phosphatases, PP1α and PP1γ. Phosphatase activity is inhibited at the area of maximal H2B S6 phosphorylation at the inner centromere by site-specific Aurora B-mediated inactivation of the PP1/RepoMan complex. The motor protein Mklp2 contributes to the relocalization of Aurora B from chromatin to the mitotic spindle during anaphase, thus alleviating Aurora B-dependent repression of the PP1/RepoMan complex and enabling dephosphorylation of H2B S6. Accordingly, dysregulation of Mklp2 levels, as commonly observed in tumour cells, leads to the lack of H2B S6 dephosphorylation during early anaphase, which might contribute to chromosomal instability.
Topics: Aurora Kinase B; Phosphorylation; Humans; Histones; Mitosis; Protein Phosphatase 1; Cell Cycle Proteins; HeLa Cells; Spindle Apparatus; Centromere; Nuclear Proteins
PubMed: 38806145
DOI: 10.1098/rsob.230460 -
Cell Reports Jun 2024Survival from UV-induced DNA lesions relies on nucleotide excision repair (NER) and the Mec1 DNA damage response (DDR). We study DDR and NER in aging cells and find that...
Survival from UV-induced DNA lesions relies on nucleotide excision repair (NER) and the Mec1 DNA damage response (DDR). We study DDR and NER in aging cells and find that old cells struggle to repair DNA and activate Mec1. We employ pharmacological and genetic approaches to rescue DDR and NER during aging. Conditions activating Snf1 rescue DDR functionality, but not NER, while inhibition of the TORC1-Sch9 axis restores NER and enhances DDR by tuning PP2A activity, specifically in aging cells. Age-related repair deficiency depends on Snf1-mediated phosphorylation of Sch9 on Ser160 and Ser163. PP2A activity in old cells is detrimental for DDR and influences NER by modulating Snf1 and Sch9. Hence, the DDR and repair pathways in aging cells are influenced by the metabolic tuning of opposing AMPK and TORC1 networks and by PP2A activity. Specific Sch9 phospho-isoforms control DDR and NER efficiency, specifically during aging.
Topics: DNA Repair; DNA Damage; Saccharomyces cerevisiae Proteins; Cellular Senescence; Phosphorylation; Saccharomyces cerevisiae; Protein Serine-Threonine Kinases; Protein Phosphatase 2; Intracellular Signaling Peptides and Proteins; Aging
PubMed: 38805395
DOI: 10.1016/j.celrep.2024.114281 -
Life Science Alliance Aug 2024FK506-binding protein 52 (FKBP52) is a member of the FKBP family of proline isomerases. FKBP52 is up-regulated in various cancers and functions as a positive regulator...
FK506-binding protein 52 (FKBP52) is a member of the FKBP family of proline isomerases. FKBP52 is up-regulated in various cancers and functions as a positive regulator of steroid hormone receptors. Depletion of FKBP52 is known to inhibit cell proliferation; however, the detailed mechanism remains poorly understood. In this study, we found that FKBP52 depletion decreased transcription, leading to stabilization of p53, and suppressed cell proliferation. We identified NFATc1 and NFATc3 as transcription factors that regulate We also found that FKBP52 associated with NFATc3 and facilitated its nuclear translocation. In addition, calcineurin, a well-known Ca phosphatase essential for activation of NFAT, plays a role in transcription. Supporting this notion, expression was found to be regulated by intracellular Ca Taken together, these findings reveal a new role of FKBP52 in promoting cell proliferation via the NFAT-MDM2-p53 axis, and indicate that inhibition of FKBP52 could be a new therapeutic tool to activate p53 and inhibit cell proliferation.
Topics: Humans; Tumor Suppressor Protein p53; Tacrolimus Binding Proteins; Cell Proliferation; NFATC Transcription Factors; Proto-Oncogene Proteins c-mdm2; Cell Line, Tumor; Calcium; Calcineurin; Gene Expression Regulation, Neoplastic; Neoplasms; Signal Transduction
PubMed: 38803221
DOI: 10.26508/lsa.202302426 -
European Journal of Cell Biology Jun 2024The Microphthalmia-associated Transcription Factor (MITF) governs numerous cellular and developmental processes. In mice, it promotes specification and differentiation...
The Microphthalmia-associated Transcription Factor (MITF) governs numerous cellular and developmental processes. In mice, it promotes specification and differentiation of the retinal pigmented epithelium (RPE), and in humans, some mutations in MITF induce congenital eye malformations. Herein, we explore the function and regulation of Mitf in Drosophila eye development and uncover two roles. We find that knockdown of Mitf results in retinal displacement (RDis), a phenotype associated with abnormal eye formation. Mitf functions in the peripodial epithelium (PE), a retinal support tissue akin to the RPE, to suppress RDis, via the Hippo pathway effector Yorkie (Yki). Yki physically interacts with Mitf and can modify its transcriptional activity in vitro. Severe loss of Mitf, instead, results in the de-repression of retinogenesis in the PE, precluding its development. This activity of Mitf requires the protein phosphatase 2 A holoenzyme STRIPAK-PP2A, but not Yki; Mitf transcriptional activity is potentiated by STRIPAK-PP2A in vitro and in vivo. Knockdown of STRIPAK-PP2A results in cytoplasmic retention of Mitf in vivo and in its decreased stability in vitro, highlighting two potential mechanisms for the control of Mitf function by STRIPAK-PP2A. Thus, Mitf functions in a context-dependent manner as a key determinant of form and fate in the Drosophila eye progenitor epithelium.
Topics: Animals; Drosophila Proteins; Microphthalmia-Associated Transcription Factor; YAP-Signaling Proteins; Trans-Activators; Nuclear Proteins; Eye; Protein Phosphatase 2; Drosophila melanogaster; Epithelium; Cell Differentiation; Homeodomain Proteins
PubMed: 38776620
DOI: 10.1016/j.ejcb.2024.151421 -
Stem Cell Research Jun 2024Spinocerebellar ataxia type 12 (SCA12) is caused by a CAG expansion mutation in PPP2R2B, a gene encoding brain-specific regulatory units of protein phosphatase 2A...
Spinocerebellar ataxia type 12 (SCA12) is caused by a CAG expansion mutation in PPP2R2B, a gene encoding brain-specific regulatory units of protein phosphatase 2A (PP2A); while normal alleles carry 4 to 31 triplets, the disease alleles carry 43 to 78 triplets. Here, by CRISPR/Cas9n genome editing, we have generated a human heterozygous SCA12 iPSC line with 73 triplets for the mutant allele. The heterozygous SCA12 iPSCs have normal karyotype, express pluripotency markers and are able to differentiate into the three germ layers.
Topics: Humans; Induced Pluripotent Stem Cells; Gene Editing; Spinocerebellar Ataxias; Heterozygote; Mutation; Cell Line; CRISPR-Cas Systems; Protein Phosphatase 2; Nerve Tissue Proteins
PubMed: 38759410
DOI: 10.1016/j.scr.2024.103441 -
The Journal of Biological Chemistry Jun 2024Host anti-inflammatory responses are critical for the progression of visceral leishmaniasis, and the pleiotropic cytokine interleukin (IL)-33 was found to be upregulated...
Host anti-inflammatory responses are critical for the progression of visceral leishmaniasis, and the pleiotropic cytokine interleukin (IL)-33 was found to be upregulated in infection. Here, we documented that IL-33 induction is a consequence of elevated cAMP-mediated exchange protein activated by cAMP (EPAC)/calcineurin-dependent signaling and essential for the sustenance of infection. Leishmania donovani-infected macrophages showed upregulation of IL-33 and its neutralization resulted in decreased parasite survival and increased inflammatory responses. Infection-induced cAMP was involved in IL-33 production and of its downstream effectors PKA and EPAC, only the latter was responsible for elevated IL-33 level. EPAC initiated Rap-dependent phospholipase C activation, which triggered the release of intracellular calcium followed by calcium/calmodulin complex formation. Screening of calmodulin-dependent enzymes affirmed involvement of the phosphatase calcineurin in cAMP/EPAC/calcium/calmodulin signaling-induced IL-33 production and parasite survival. Activated calcineurin ensured nuclear localization of the transcription factors, nuclear factor of activated T cell 1 and hypoxia-inducible factor 1 alpha required for IL-33 transcription, and we further confirmed this by chromatin immunoprecipitation assay. Administering specific inhibitors of nuclear factor of activated T cell 1 and hypoxia-inducible factor 1 alpha in BALB/c mouse model of visceral leishmaniasis decreased liver and spleen parasite burden along with reduction in IL-33 level. Splenocyte supernatants of inhibitor-treated infected mice further documented an increase in tumor necrosis factor alpha and IL-12 level with simultaneous decrease of IL-10, thereby indicating an overall disease-escalating effect of IL-33. Thus, this study demonstrates that cAMP/EPAC/calcineurin signaling is crucial for the activation of IL-33 and in effect creates anti-inflammatory responses, essential for infection.
Topics: Animals; Calcineurin; Leishmania donovani; Cyclic AMP; Mice; Leishmaniasis, Visceral; Signal Transduction; Interleukin-33; Mice, Inbred BALB C; Macrophages; Guanine Nucleotide Exchange Factors
PubMed: 38750790
DOI: 10.1016/j.jbc.2024.107366 -
Journal of Applied Oral Science :... 2024Studies have highlighted numerous benefits of ozone therapy in the field of medicine and dentistry, including its antimicrobial efficacy against various pathogenic...
OBJECTIVE
Studies have highlighted numerous benefits of ozone therapy in the field of medicine and dentistry, including its antimicrobial efficacy against various pathogenic microorganisms, its ability to modulate the immune system effectively, reduce inflammation, prevent hypoxia, and support tissue regeneration. However, its effects on dental extraction healing remain to be elucidated. .Therefore, this study aimed to evaluate the effects of systemically administered ozone (O3) at different doses in the healing of dental extraction sockets in rats.
METHODOLOGY
To this end, 72 Wistar rats were randomly divided into four groups after extraction of the right upper central incisor: Group C - control, no systemic treatment; Group OZ0.3 - animals received a single dose of 0.3 mg/kg O3; Group OZ0.7 - a single dose of 0.7 mg/kg O3; and Group OZ1.0 - a single dose of 1.0 mg/kg O3, intraperitoneally. In total, six animals from each group were euthanized at 7, 14, and 21 days after the commencement of treatment. Bone samples were harvested and further analyzed by descriptive histology, histomorphometry, and immunohistochemistry for osteocalcin (OCN) and tartrate-resistant acid phosphatase (TRAP) protein expression.
RESULTS
All applied doses of O3 were shown to increase the percentage of bone tissue (PBT) after 21 days compared to group C. After 14 days, the OZ0.7 and OZ1.0 groups showed significantly higher PBT when compared to group C. The OZ1.0 group presented the most beneficial results regarding PBT among groups, which denotes a dose-dependent response. OCN immunostaining was higher in all groups at 21 days. However, after seven and 14 days, the OZ1.0 group showed a significant increase in OCN immunostaining compared to C group. No differences in TRAP+ osteoclasts were found between groups and time points.
CONCLUSION
Therefore, O3 therapy at higher doses might be beneficial for bone repair of the alveolar socket following tooth extraction.
Topics: Animals; Ozone; Rats, Wistar; Tooth Extraction; Tooth Socket; Wound Healing; Tartrate-Resistant Acid Phosphatase; Immunohistochemistry; Osteocalcin; Time Factors; Male; Random Allocation; Reproducibility of Results; Treatment Outcome; Reference Values
PubMed: 38747807
DOI: 10.1590/1678-7757-2023-0412 -
The Journal of Clinical Investigation May 2024Idiopathic systemic capillary leak syndrome (ISCLS) is a rare, recurrent condition with dramatically increased blood vessel permeability and, therefore, induction of...
Idiopathic systemic capillary leak syndrome (ISCLS) is a rare, recurrent condition with dramatically increased blood vessel permeability and, therefore, induction of systemic edema, which may lead to organ damage and death. In this issue of the JCI, Ablooglu et al. showed that ISCLS vessels were hypersensitive to agents known to increase vascular permeability, using human biopsies, cell culture, and mouse models. Several endothelium-specific proteins that regulate endothelial junctions were dysregulated and thereby compromised the vascular barrier. These findings suggest that endothelium-intrinsic dysregulation underlies hyperpermeability and implicate the cytoplasmic serine/threonine protein phosphatase 2A (PP2A) as a potential drug target for the treatment of ISCLS.
Topics: Humans; Animals; Mice; Capillary Leak Syndrome; Protein Phosphatase 2; Capillary Permeability; Endothelium, Vascular
PubMed: 38747291
DOI: 10.1172/JCI180795