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1.
ObjectivesHepatitis B virus X (HBx) is closely associated with HBV‐related hepatocarcinogenesis via the inactivation of tumour suppressors. Protein phosphatase 2A (PP2A) regulatory subunit B56 gamma (B56γ), as a tumour suppressor, plays a critical role in regulating cellular phosphorylation signals via dephosphorylation of signalling proteins. However, the underlying mechanism that B56γ involved in regulating HBx‐associated hepatocarcinogenesis phenotypes and mediating anti‐HBx antibody‐mediated tumour suppression remains unknown.Materials and MethodsWe used bioinformatics analysis, paired HCC patient specimens, HBx transgenic (HBx‐Tg) mice, xenograft nude mice, HBV stable replication in the HepG2.2.15 cells, and anti‐HBx antibody intervention to systematically evaluate the biological function of protein kinase B (AKT) dephosphorylation through B56γ in HBx‐associated hepatocarcinogenesis.ResultsBioinformatics analysis revealed that AKT, matrix metalloproteinase 2 (MMP2), and MMP9 were markedly upregulated, while cell migration and viral carcinogenesis pathways were activated in HBV‐infected liver tissues and HBV‐associated HCC tissues. Our results demonstrated that HBx‐expression promotes AKT phosphorylation (p‐AKTThr308/Ser473), mediating the migration and invasion phenotypes in vivo and in vitro. Importantly, in clinical samples, HBx and B56γ were downregulated in HBV‐associated HCC tumour tissues compared with peritumor tissues. Moreover, intervention with site‐directed mutagenesis (AKTT308A, AKTS473A) of p‐AKTThr308/Ser473 mimics dephosphorylation, genetics‐based B56γ overexpression, and intracellular anti‐HBx antibody inhibited cell growth, migration, and invasion in HBx‐expressing HCC cells.ConclusionsOur results demonstrated that B56γ inhibited HBV/HBx‐dependent hepatocarcinogenesis by regulating the dephosphorylation of p‐AKTThr308/Ser473 in HCC cells. The intracellular anti‐HBx antibody and the activator of B56γ may provide a multipattern chemopreventive strategy against HBV‐related HCC.

Schematic diagram of PP2A‐B56γ mediated the dephosphorylation of p‐AKTThr308/Ser473 in HBx‐expressing HCC cells to regulate the migration and invasion phenotypes of HBV/HBx‐related hepatocarcinogenesis. In current study, HBx‐expression induced the phosphorylation of specific AKT sites (p‐AKTThr308/Ser473) involved in mediating the migration and invasion phenotypes of HCC cells. The inducible upregulation of B56γ mediated the dephosphorylation of p‐AKTThr308/Ser473 in HBx‐expressing HCC cells. Specific blockade of HBx‐expression via pTT5‐anti‐HBx plasmid‐mediated targeting intracellular anti‐HBx mAb production and genetic activation of B56γ would help to target the p‐AKTThr308/Ser473‐MMP2/9 signalling axis to mediate the multipattern chemoprevention and intervention in HBV/HBx‐related hepatocarcinogenesis.  相似文献   

2.
The molecular mechanism of hepatic cell growth and differentiation is ill defined. In the present study, we examined the putative role of tyrosine phosphorylation in normal rat liver development and in an in vitro model, the α-fetoprotein-producing (AFP+) and AFP-nonproducing (AFP) clones of the McA-RH 7777 rat hepatoma. We demonstrated in vivo and in vitro that the AFP+ phenotype is clearly associated with enhanced tyrosine phosphorylation, as assessed by immunoblotting and flow cytometry. Moreover, immunoprecipitation of proteins with anti-phosphotyrosine antibody showed that normal fetal hepatocytes expressed the same phosphorylation pattern as stable AFP+ clones and likewise for adult hepatocytes and AFP clones. The tyrosine phosphorylation of several proteins, including the β-subunit of the insulin receptor, insulin receptor substrate-1, p85 regulatory subunit of phosphatidylinositol-3-kinase, and ras-guanosine triphosphatase-activating protein, was observed in AFP+ clones, whereas the same proteins were not phosphorylated in AFP clones. We also observed that fetal hepatocytes and the AFP+ clones express 4 times more of the insulin receptor β-subunit compared with adult hepatocytes and AFP clones and, accordingly, that these AFP+ clones were more responsive to exogenous insulin in terms of protein tyrosine phosphorylation. Finally, growth rate in cells of AFP+ clones was higher than that measured in cells of AFP clones, and inhibition of phosphatidylinositol-3-kinase by LY294002 and Wortmannin blocked insulin- and serum-stimulated DNA synthesis only in cells of AFP+ clones. These studies provide evidences in support of the hypothesis that signaling via insulin prevents hepatocyte differentiation by promoting fetal hepatocyte growth.  相似文献   

3.
Hutchinson‐Gilford progeria syndrome (HGPS) is a lethal premature aging disorder without an effective therapeutic regimen. Because of their targetability and influence on gene expression, microRNAs (miRNAs) are attractive therapeutic tools to treat diseases. Here we identified that hsa‐miR‐59 (miR‐59) was markedly upregulated in HGPS patient cells and in multiple tissues of an HGPS mouse model (Lmna G609G/G609G ), which disturbed the interaction between RNAPII and TFIIH, resulting in abnormal expression of cell cycle genes by targeting high‐mobility group A family HMGA1 and HMGA2. Functional inhibition of miR‐59 alleviated the cellular senescence phenotype of HGPS cells. Treatment with AAV9‐mediated anti‐miR‐59 reduced fibrosis in the quadriceps muscle, heart, and aorta, suppressed epidermal thinning and dermal fat loss, and yielded a 25.5% increase in longevity of Lmna G609G/G609G mice. These results identify a new strategy for the treatment of HGPS and provide insight into the etiology of HGPS disease.  相似文献   

4.
Previous studies have found that alpha‐fetoprotein (AFP) can promote the proliferation of hepatoma cells and accelerate the progression of hepatocellular carcinoma (HCC). However, the exact mechanism of action remains unclear. Recent bioinformatics studies have predicted the possible interaction between AFP and retinoic acid receptors (RARs). Thus, the purpose of this study was to investigate the molecular mechanism through which AFP promotes tumour cell proliferation by interfering with the RA‐RAR signal pathway. Our data indicated that AFP could significantly promote the proliferation and weaken ATRA‐induced apoptosis of hepatoma cells. Besides, cytoplasmic AFP interacts with RAR, disrupting its entrance into the nucleus, which in turn affects the expression of the Bcl‐2 gene. In addition, knockdown of AFP in HepG2 cells was synchronously associated with an incremental increase of RAR binding to DNA, as well as down‐regulation of Bcl‐2; the opposite effect was observed in AFP gene‐transfected HLE cells. Moreover, a similar effect of AFP was detected in tumour tissues with high serum AFP, but not in adjacent non‐cancerous liver tissues, or HCC tissues with low serum AFP levels. These results indicate that AFP acts as signalling molecule and prevents RAR from entering into the nucleus by interacting with RAR, thereby promoting the expression of Bcl‐2. Our data reveal a novel mechanism through which AFP regulates Bcl‐2 expression and further suggest that AFP may be used as a novel target for treating HCC.  相似文献   

5.
Circular RNAs (circRNAs) have been demonstrated to play important roles in cancer progress. However, the roles in hepatocellular carcinoma (HCC) are still unclear. Here, we found has_circRNA_001306 (circ_1306) was up‐regulated in HCC tissues and cell lines. Knockdown the expression circ_1306 significantly suppressed HCC cell proliferation and induced the cell apoptosis in vitro and in vivo. Furthermore, we identified circ_1306 could up‐regulate the expression of CDK16 by sponging miR‐584‐5p. The expression of miR‐584‐5p was decreased, and the expression of CDK16 was increased in HCC tissues and cell lines. Meanwhile, either knockdown of miR‐584‐5p or overexpression of CDK16 could suppress the HCC cell proliferation. In vivo, overexpression of miR‐584‐5p or knockdown of circ_1306 could inhibit the expression of CDK16, and suppress tumour growth. Altogether, our findings suggested that circ_1306 could promoter HCC progress by miR‐584‐5p/CDK16 axis, which provided a novel marker for HCC diagnosis and treatment.  相似文献   

6.
Macrophages are fundamental components of inflammation in post‐myocardial infarction (MI) and contribute to adverse cardiac remodelling and heart failure. However, the regulatory mechanisms in macrophage activation have not been fully elucidated. Previous studies showed that myeloid‐associated immunoglobulin–like receptor II (MAIR‐II) is involved in inflammatory responses in macrophages. However, its role in MI is unknown. Thus, this study aimed to determine a novel role and mechanism of MAIR‐II in MI. We first identified that MAIR‐II–positive myeloid cells were abundant from post‐MI days 3 to 5 in infarcted hearts of C57BL/6J (WT) mice induced by permanent left coronary artery ligation. Compared to WT, MAIR‐II–deficient (Cd300c2 −/−) mice had longer survival, ameliorated cardiac remodelling, improved cardiac function and smaller infarct sizes. Moreover, we detected lower pro‐inflammatory cytokine and fibrotic gene expressions in Cd300c2 −/−‐infarcted hearts. These mice also had less infiltrating pro‐inflammatory macrophages following MI. To elucidate a novel molecular mechanism of MAIR‐II, we considered macrophage activation by Toll‐like receptor (TLR) 9–mediated inflammation. In vitro, we observed that Cd300c2 −/− bone marrow–derived macrophages stimulated by a TLR9 agonist expressed less pro‐inflammatory cytokines compared to WT. In conclusion, MAIR‐II may enhance inflammation via TLR9‐mediated macrophage activation in MI, leading to adverse cardiac remodelling and poor prognosis.  相似文献   

7.
Mitochondrial homeostasis is essential for providing cellular energy, particularly in resource‐demanding neurons, defects in which cause neurodegeneration, but the function of interferons (IFNs) in regulating neuronal mitochondrial homeostasis is unknown. We found that neuronal IFN‐β is indispensable for mitochondrial homeostasis and metabolism, sustaining ATP levels and preventing excessive ROS by controlling mitochondrial fission. IFN‐β induces events that are required for mitochondrial fission, phosphorylating STAT5 and upregulating PGAM5, which phosphorylates serine 622 of Drp1. IFN‐β signaling then recruits Drp1 to mitochondria, oligomerizes it, and engages INF2 to stabilize mitochondria–endoplasmic reticulum (ER) platforms. This process tethers damaged mitochondria to the ER to separate them via fission. Lack of neuronal IFN‐β in the Ifnb –/– model of Parkinson disease (PD) disrupts STAT5‐PGAM5‐Drp1 signaling, impairing fission and causing large multibranched, damaged mitochondria with insufficient ATP production and excessive oxidative stress to accumulate. In other PD models, IFN‐β rescues dopaminergic neuronal cell death and pathology, associated with preserved mitochondrial homeostasis. Thus, IFN‐β activates mitochondrial fission in neurons through the pSTAT5/PGAM5/S622Drp1 pathway to stabilize mitochondria/ER platforms, constituting an essential neuroprotective mechanism.  相似文献   

8.
The sodium–potassium–chloride transporter NKCC1 of the SLC12 family performs Na+‐dependent Cl‐ and K+‐ion uptake across plasma membranes. NKCC1 is important for regulating cell volume, hearing, blood pressure, and regulation of hyperpolarizing GABAergic and glycinergic signaling in the central nervous system. Here, we present a 2.6 Å resolution cryo‐electron microscopy structure of human NKCC1 in the substrate‐loaded (Na+, K+, and 2 Cl) and occluded, inward‐facing state that has also been observed for the SLC6‐type transporters MhsT and LeuT. Cl binding at the Cl1 site together with the nearby K+ ion provides a crucial bridge between the LeuT‐fold scaffold and bundle domains. Cl‐ion binding at the Cl2 site seems to undertake a structural role similar to conserved glutamate of SLC6 transporters and may allow for Cl‐sensitive regulation of transport. Supported by functional studies in mammalian cells and computational simulations, we describe a putative Na+ release pathway along transmembrane helix 5 coupled to the Cl2 site. The results provide insight into the structure–function relationship of NKCC1 with broader implications for other SLC12 family members.  相似文献   

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ObjectivesThe purpose of the study aims to understand the regeneration process and its cytology mechanism in economic echinoderms.Materials and MethodsThe intestine regeneration process of Apostichopus japonicus was investigated by immunohistochemistry and the cell proliferation was detected by immunofluorescence and flow cytometry. Fibroblast growth factor 4 of A. japonicus (AjFGF4) was screened by RNA‐seq analysis and validated to regulate cell proliferation by siAjFGF4 and recombinant‐AjFGF4 treatment. The binding and co‐localization of AjFGF4 and AjFGFR2 were verified by Co‐IP, GST‐pull down, and immunofluorescence. Then, the AjFGF4‐AjFGFR2‐ERK‐cell cycle axis was examined by western blot, immunofluorescence, and flow cytometry techniques.ResultsThe mesentery was served as the epicenter of intestinal regeneration via activating cell proliferation and other cellular events. Mechanically, AjFGF4‐mediated cell proliferation was dependent on the binding to its receptor AjFGFR2, and then triggered the conserved ERK–MAPK pathway but not JNK and p38 pathway. The activated ERK–MAPK subsequently mediated the expression of cell cycle regulatory proteins of CDK2, Cyclin A, and Cyclin B to promote cell proliferation.ConclusionsWe provide the first functional evidence that AjFGF4‐AjFGFR2‐ERK‐cell cycle axis mediated cell proliferation was the engine for mesentery‐derived intestine regeneration in echinoderms.

Mesentery served as the epicenter of intestinal regeneration to form a new intestine mainly via cell proliferation. Fibroblast growth factor 4 (AjFGF4) was found to regulate cell proliferation by specifically binding to AjFGFR2, and then triggered the conserved ERK–MAPK pathway but not JNK and p38 pathway. The activated ERK–MAPK subsequently mediated the expression of cell cycle regulatory proteins of CDK2, Cyclin A, and Cyclin B to promote cell proliferation.  相似文献   

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DNA damage is a causative factor in ageing of the vasculature and other organs. One of the most important vascular ageing features is reduced nitric oxide (NO)soluble guanylate cyclase (sGC)—cyclic guanosine monophosphate (cGMP) signaling. We hypothesized that the restoration of NO‐sGC‐cGMP signaling with an sGC activator (BAY 54–6544) may have beneficial effects on vascular ageing and premature death in DNA repair‐defective mice undergoing accelerated ageing. Eight weeks of treatment with a non‐pressor dosage of BAY 54–6544 restored the decreased in vivo microvascular cutaneous perfusion in progeroid Ercc1 ∆/− mice to the level of wild‐type mice. In addition, BAY 54–6544 increased survival of Ercc1 ∆/− mice. In isolated Ercc1 ∆/− aorta, the decreased endothelium‐independent vasodilation was restored after chronic BAY 54–6544 treatment. Senescence markers p16 and p21, and markers of inflammation, including Ccl2, Il6 in aorta and liver, and circulating IL‐6 and TNF‐α were increased in Ercc1 ∆/− , which was lowered by the treatment. Expression of antioxidant genes, including Cyb5r3 and Nqo1, was favorably changed by chronic BAY 54–6544 treatment. In summary, BAY 54–6544 treatment improved the vascular function and survival rates in mice with accelerated ageing, which may have implication in prolonging health span in progeria and normal ageing.  相似文献   

14.
As a member of the deoxyribonuclease 1 family, DNASE1L3 plays a significant role both inside and outside the cell. However, the role of DNASE1L3 in hepatocellular carcinoma (HCC) and its molecular basis remains to be further investigated. In this study, we report that DNASE1L3 is downregulated in clinical HCC samples and evaluate the relationship between its expression and HCC clinical features. In vivo and in vitro experiments showed that DNASE1L3 negatively regulates the proliferation, invasion and metastasis of HCC cells. Mechanistic studies showed that DNASE1L3 recruits components of the cytoplasmic β‐catenin destruction complex (GSK‐3β and Axin), promotes the ubiquitination degradation of β‐catenin, and inhibits its nuclear transfer, thus, decreasing c‐Myc, P21 and P27 level. Ultimately, cell cycle and EMT signals are restrained. In general, this study provides new insight into the mechanism for HCC and suggests that DNASE1L3 can become a considerable target for HCC.

Decreased expression of DNASE1L3 is associated with poor prognosis in patients with HCC DNASE1L3 inhibits the proliferation and cell cycle of HCC cells in vitro and promotes the invasion and metastasis of HCC cells DNASE1L3 inhibits the tumorigenicity and metastasis of HCC cells in vivo DNASE1L3 interacts with β‐catenin and promotes its binding to the β‐catenin destroying complex DNASE1L3 interacts with P21 and stabilizes P21 by mediating the deubiquitin activity  相似文献   

15.
METTL3 is an important regulatory molecule in the process of RNA biosynthesis. It mainly regulates mRNA translation, alternative splicing and microRNA maturation by mediating m6A‐dependent methylation. Interleukin 1β (IL‐1β) is an important inducer of cartilage degeneration that can induce an inflammatory cascade reaction in chondrocytes and inhibit the normal biological function of cells. However, it is unclear whether IL‐1β is related to METTL3 expression or plays a regulatory role in endplate cartilage degeneration. In this study, we found that the expression level of METTL3 and methylation level of m6A in human endplate cartilage with different degrees of degeneration were significantly different, indicating that the methylation modification of m6A mediated by METTL3 was closely related to the degeneration of human endplate cartilage. Next, through a series of functional experiments, we found that miR‐126‐5p can play a significant role in IL‐1β–induced degeneration of endplate chondrocytes. Moreover, we found that miR‐126‐5p can inhibit the PI3K/Akt signalling pathway by targeting PIK3R2 gene, leading to the disorder of cell vitality and functional metabolism. To further determine whether METTL3 could regulate miR‐126‐5p maturation, we first confirmed that METTL3 can bind the key protein underlying pri‐miRNA processing, DGCR8. Additionally, when METTL3 expression was inhibited, the miR‐126‐5p maturation process was blocked. Therefore, we hypothesized that METTL3 can promote cleavage of pri‐miR‐126‐5p and form mature miR‐126‐5p by combining with DGCR8.  相似文献   

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Tris (dibenzylideneacetone) dipalladium (Tris DBA), a small‐molecule palladium complex, can inhibit cell growth and proliferation in pancreatic cancer, lymphocytic leukaemia and multiple myeloma. Given that this compound is particularly active against B‐cell malignancies, we have been suggested that it can alleviate immune complexes (ICs)–mediated conditions, especially IgA nephropathy (IgAN). The therapeutic effects of Tris DBA on glomerular cell proliferation and renal inflammation and mechanism of action were examined in a mouse model of IgAN. Treatment of IgAN mice with Tris DBA resulted in markedly improved renal function, albuminuria and renal pathology, including glomerular cell proliferation, neutrophil infiltration, sclerosis and periglomerular inflammation in the renal interstitium, together with (Clin J Am Soc Nephrol. 2011, 6, 1301‐1307) reduced mitochondrial ROS generation; (Am J Physiol‐Renal Physiol. 2011. 301, F1218‐F1230) differentially regulated autophagy and NLRP3 inflammasome; (Clin J Am Soc Nephrol. 2012, 7, 427‐436) inhibited phosphorylation of JNK, ERK and p38 MAPK signalling pathways, and priming signal of the NLRP3 inflammasome; and (Free Radic Biol Med. 2013, 61, 285‐297) blunted NLRP3 inflammasome activation through SIRT1‐ and SIRT3‐mediated autophagy induction, in renal tissues or cultured macrophages. In conclusion, Tris DBA effectively ameliorated the mouse IgAN model and targeted signalling pathways downstream of ICs‐mediated interaction, which is a novel immunomodulatory strategy. Further development of Tris DBA as a therapeutic candidate for IgAN is warranted.  相似文献   

19.
Stem cell senescence is an important cause of aging. Delaying senescence may present a novel way to combat aging and age‐associated diseases. This study provided a mechanistic insight into the protective effect of ganoderic acid D (GA‐D) against human amniotic mesenchymal stem cell (hAMSCs) senescence. GA‐D, a Ganoderma lucidum‐derived triterpenoid, markedly prevented hAMSCs senescence via activating the Ca2+ calmodulin (CaM)/CaM‐dependent protein kinase II (CaMKII)/nuclear erythroid 2‐related factor 2 (Nrf2) axis, and 14‐3‐3ε was identified as a target of GA‐D. 14‐3‐3ε‐encoding gene (YWHAE) knockdown in hAMSCs reversed the activation of the CaM/CaMKII/Nrf2 signals to attenuate the GA‐D anti‐aging effect and increase senescence‐associated β‐galactosidase (SA‐β‐gal), p16 and p21 expression levels, including reactive oxygen species (ROS) production, thereby promoting cell cycle arrest and decreasing differentiation potential. YWHAE overexpression maintained or slightly enhanced the GA‐D anti‐aging effect. GA‐D prevented d‐galactose‐caused aging in mice by significantly increasing the total antioxidant capacity, as well as superoxide dismutase and glutathione peroxidase activity, and reducing the formation of malondialdehyde, advanced glycation end products, and receptor of advanced glycation end products. Consistent with the protective mechanism of GA‐D against hAMSCs senescence, GA‐D delayed the senescence of bone‐marrow mesenchymal stem cells in this aging model in vivo, reduced SA‐β‐gal and ROS production, alleviated cell cycle arrest, and enhanced cell viability and differentiation via regulating 14‐3‐3ε and CaM/CaMKII/Nrf2 axis. Therefore, GA‐D retards hAMSCs senescence by targeting 14‐3‐3ε to activate the CaM/CaMKII/Nrf2 signaling pathway. Furthermore, the in vivo GA‐D anti‐aging effect may involve the regulation of stem cell senescence via the same signal axis.  相似文献   

20.
Oral lichen planus (OLP) is a T cell–mediated chronic inflammatory disease with uncertain aetiology. Exosomes are nanosized particles with biological capacities. Here, we aimed to study the effects of T cell–derived exosomes (T‐exos) on the pathogenesis of OLP and its mechanism. T‐exos were incubated with Jurkat cells for 48 hours, and 26 cytokines in the supernatant were measured by luminex assay. The expression of macrophage inflammatory protein (MIP)‐1α/β was detected using immunohistochemistry and ELISA; that of CCR1/3/5 on peripheral T cells was determined by flow cytometry. Transwell assay was performed to investigate the chemotactic effect of MIP‐1α/β, and cells in the lower chambers were examinated by flow cytometry. As a result, OLP T‐exos elevated the production of MIP‐1α/β, which were highly expressed in OLP tissues and plasma. CCR1/5 were markedly expressed on OLP peripheral T cells, and the majority of CCR1/5+ T cells were CD8+ T cells. Besides, MIP‐1α/β promoted the migration of OLP mononuclear cells, while inhibiting CCR1/5 significantly decreased the trafficking of mononuclear cells, especially that of CD8+ T cells. Conclusively, OLP T‐exos‐induced MIP‐1α/β may drive the trafficking of CD8+ T cells after binding with CCR1/5 in OLP, contributing to the development of OLP.  相似文献   

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