• Reproductive and Developmental Biology
• /
• 제30권2호
• /
• pp.143-156
• /
• 2006

Major characteristics of embryonic stem cells (ESCs) are sustaining of sternness and pluripotency by self-renewal. In this report, transcriptional profiles of the molecules in the developmentally important signaling pathways including Wnt, BMP4, $TGF-\beta$, RTK, Hh, Notch, and JAK/STAT signaling pathways were investigated to understand the self-renewal of mouse ESCs (mESCs), J1 line, and compared with the NIH3T3 cell line and mouse embryonic fibroblast (MEF) cells as controls. In the Wnt signaling pathway, the expression of Wnt3 was seen widely in mESCs, suggesting that the ligand may be an important regulator for self-renewal in mESCs. In the Hh signaling pathway, the expression of Gli and N-myc were observed extensively in mESCs, whereas the expression levels of in a Shh was low, suggesting that intracellular molecules may be essential for the self-renewal of mESCs. IGF-I, IGF-II, IGF-IR and IGF-IIR of RTK signaling showed a lower expression in mESCs, these molecules related to embryo development may be restrained in mESCs. The expression levels of the Delta and HESS in Notch signaling were enriched in mESCs. The expression of the molecules related to BMP and JAK-STAT signaling pathways were similar or at a slightly lower level in mESCs compared to those in MEF and NIH3T3 cells. It is suggested that the observed differences in gene expression profiles among the signaling pathways may contribute to the self-renewal and differentiation of mESCs in a signaling-specific manner.

• Parasites, Hosts and Diseases
• /
• 제52권5호
• /
• pp.459-469
• /
• 2014

Entamoeba histolytica is a tissue-invasive protozoan parasite causing dysentery in humans. During infection of colonic tissues, amoebic trophozoites are able to kill host cells via apoptosis or necrosis, both of which trigger IL-8-mediated acute inflammatory responses. However, the signaling pathways involved in host cell death induced by E. histolytica have not yet been fully defined. In this study, we examined whether calpain plays a role in the cleavage of pro-survival transcription factors during cell death of colonic epithelial cells, induced by live E. histolytica trophozoites. Incubation with amoebic trophozoites induced activation of m-calpain in a time- and dose-dependent manner. Moreover, incubation with amoebae resulted in marked degradation of STAT proteins (STAT3 and STAT5) and NF-${\kappa}B$ (p65) in Caco-2 cells. However, $I{\kappa}B$, an inhibitor of NF-${\kappa}B$, was not cleaved in Caco-2 cells following adherence of E. histolytica. Entamoeba-induced cleavage of STAT proteins and NF-${\kappa}B$ was partially inhibited by pretreatment of cells with a cell-permeable calpain inhibitor, calpeptin. In contrast, E. histolytica did not induce cleavage of caspase-3 in Caco-2 cells. Furthermore, pretreatment of Caco-2 cells with a calpain inhibitor, calpeptin (but not the pan-caspase inhibitor, z-VAD-fmk) or m-calpain siRNA partially reduced Entamoeba-induced DNA fragmentation in Caco-2 cells. These results suggest that calpain plays an important role in E. histolytica-induced degradation of NF-${\kappa}B$ and STATs in colonic epithelial cells, which ultimately accelerates cell death.

• Molecules and Cells
• /
• 제45권4호
• /
• pp.257-272
• /
• 2022

In addition to inducing apoptosis, caspase inhibition contributes to necroptosis and/or autophagy depending on the cell type and cellular context. In macrophages, necroptosis can be induced by co-treatment with Toll-like receptor (TLR) ligands (lipopolysaccharide [LPS] for TLR4 and polyinosinic-polycytidylic acid [poly I:C] for TLR3) and a cell-permeable pan-caspase inhibitor zVAD. Here, we elucidated the signaling pathways and molecular mechanisms of cell death. We showed that LPS/zVAD- and poly I:C/zVAD-induced cell death in bone marrow-derived macrophages (BMDMs) was inhibited by receptor-interacting protein kinase 1 (RIP1) inhibitor necrostatin-1 and autophagy inhibitor 3-methyladenine. Electron microscopic images displayed autophagosome/autolysosomes, and immunoblotting data revealed increased LC3II expression. Although zVAD did not affect LPS- or poly I:C-induced activation of IKK, JNK, and p38, it enhanced IRF3 and STAT1 activation as well as type I interferon (IFN) expression. In addition, zVAD inhibited ERK and Akt phosphorylation induced by LPS and poly I:C. Of note, zVAD-induced enhancement of the IRF3/IFN/STAT1 axis was abolished by necrostatin-1, while zVAD-induced inhibition of ERK and Akt was not. Our data further support the involvement of autocrine IFNs action in reactive oxygen species (ROS)-dependent necroptosis, LPS/zVAD-elicited ROS production was inhibited by necrostatin-1, neutralizing antibody of IFN receptor (IFNR) and JAK inhibitor AZD1480. Accordingly, both cell death and ROS production induced by TLR ligands plus zVAD were abrogated in STAT1 knockout macrophages. We conclude that enhanced TRIF-RIP1-dependent autocrine action of IFNβ, rather than inhibition of ERK or Akt, is involved in TLRs/zVAD-induced autophagic and necroptotic cell death via the JAK/STAT1/ROS pathway.

• IMMUNE NETWORK
• /
• 제10권6호
• /
• pp.219-229
• /
• 2010

Background: N-myc downstream regulated gene 2 (NDRG2) is a member of the NDRG gene family. Our previous report indicated a possible role for NDRG2 in regulating the cytokine, interleukin-10 (IL-10), which is an important immunosuppressive cytokine. Several pathways, including p38-MAPK, NF-${\kappa}B$, and JAK/STAT, are used for IL-10 production, and the JAK/STAT pathway can be inhibited in a negative feedback loop by the inducible protein, SOCS3. In the present study, we investigated the effect of NDRG2 gene expression on IL-10 signaling pathway that is modulated via SOCS3 and STAT3. Methods: We generated NDRG2-overexpressing U937 cell line (U937-NDRG2) and treated the cells with PMA to investigate the role of NDRG2 in IL-10 production. U937 cells were also transfected with SOCS3- or NDRG2-specific siRNAs to examine whether the knockdown of SOCS3 or NDRG2 influenced IL-10 expression. Lastly, STAT3 and SOCS3 induction was measured to identify the signaling pathway that was associated with IL-10 production. Results: RT-PCR and ELISA assays showed that IL-10 was increased in U937-mock cells upon stimulation with PMA, but IL-10 was inhibited by overexpression NDRG2. After PMA treatment, STAT3 phosphorylation was decreased in a time-dependent manner in U937-mock cells, whereas it was maintained in U937-NDRG2 cells. SOCS3 was markedly reduced in U937-NDRG2 cells compared with U937-mock cells. IL-10 production after PMA stimulation was reduced in U937 cells when SOCS3 was inhibited, but this effect was less severe when NDRG2 was inhibited. Conclusion: NDRG2 expression modulates SOCS3 and STAT3 activity, eventually leading to the inhibition of IL-10 production.

• Genomics & Informatics
• /
• 제17권1호
• /
• pp.8.1-8.10
• /
• 2019

Alveolar type II cells constitute a small fraction of the total lung cell mass. However, they play an important role in many cellular processes including trans-differentiation into type I cells as well as repair of lung injury in response to toxic chemicals and respiratory pathogens. Transcription factors are the regulatory proteins dynamically modulating DNA structure and gene expression. Transcription factor profiling in microarray datasets revealed that several members of AP1, ATF, $NF-{\kappa}B$, and C/EBP families involved in diverse responses were expressed in mouse lung type II cells. A transcriptional factor signature consisting of Cebpa, Srebf1, Stat3, Klf5, and Elf3 was identified in lung type II cells, Sox9+ pluripotent lung stem cells as well as in mouse lung development. Identification of the transcription factor profile in mouse lung type II cells will serve as a useful resource and facilitate the integrated analysis of signal transduction pathways and specific gene targets in a variety of physiological conditions.

• IMMUNE NETWORK
• /
• 제22권3호
• /
• pp.25.1-25.11
• /
• 2022

IL-34 can promote osteoclast differentiation and activation, which may contribute to steroid-induced osteonecrosis of the femoral head (ONFH). Animal model was constructed in both BALB/c and IL-34 deficient mice to detect the relative expression of inflammation cytokines. Micro-CT was utilized to reveal the internal structure. In vitro differentiated osteoclast was induced by culturing bone marrow-derived macrophages with IL-34 conditioned medium or M-CSF. The relative expression of pro-inflammation cytokines, osteoclast marker genes, and relevant pathways molecules was detected with quantitative real-time RT-PCR, ELISA, and Western blot. Up-regulated IL-34 expression could be detected in the serum of ONFH patients and femoral heads of ONFH mice. IL-34 deficient mice showed the resistance to ONFH induction with the up-regulated trabecular number, trabecular thickness, bone value fraction, and down-regulated trabecular separation. On the other hand, inflammatory cytokines, such as TNF-α, IFN-γ, IL-6, IL-12, IL-2, and IL-17A, showed diminished expression in IL-34 deficient ONFH induced mice. IL-34 alone or works in coordination with M-CSF to promote osteoclastogenesis and activate ERK, STAT3, and non-canonical NF-κB pathways. These data demonstrate that IL-34 can promote the differentiation of osteoclast through ERK, STAT3, and non-canonical NF-κB pathways to aggravate steroid-induced ONFH, and IL-34 can be considered as a treatment target.

• Mycobiology
• /
• 제43권3호
• /
• pp.319-326
• /
• 2015

Fomes fomentarius is a fungus of the Polyporaceae family and is used in traditional oriental therapies. Although the anti-inflammatory activities of this species have been previously reported, the identity of the bioactive compounds responsible for this activity remains unknown. Here, we investigated whether methyl 9-oxo-(10E,12E)-octadecadienoate (FF-8) purified from F. fomentarius exerts anti-inflammatory activity in murine macrophages stimulated with lipopolysaccharide (LPS). FF-8 suppressed secretion of nitric oxide (NO) and prostaglandin $E_2$ through downregulation of inducible NO synthase and cyclooxygenase-2 expression induced by LPS. In addition, pretreatment of cells with FF-8 led to a reduction in levels of secreted inflammatory cytokines such as tumor necrosis factor-${\alpha}$ and interleukin-6 in macrophages stimulated with LPS. Conversely, FF-8 did not affect nuclear factor ${\kappa}B$, p38, c-Jun NH2-terminal kinase, and extracellular signal-regulated kinase pathways. Instead, FF-8 specifically interfered with signal transducer and activator of transcription 3 (STAT3) phosphorylation induced by LPS. Collectively, this study demonstrated that FF-8 purified from F. fomentarius suppresses inflammatory responses in macrophages stimulated with LPS by inhibiting STAT3 activation. Further studies will be required to elucidate the anti-inflammatory effect of FF-8 in vivo.

• The Korean Journal of Physiology and Pharmacology
• /
• 제26권6호
• /
• pp.457-468
• /
• 2022

It has been demonstrated that APPL1 (adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1) is involved in the regulation of several growth-related signaling pathways and thus closely associated with the development and progression of some cancers. Diallyl trisulfide (DAT), a garlic-derived bioactive compound, exerts selective cytotoxicity to various human cancer cells through interfering with pro-survival signaling pathways. However, whether and how DAT affects survival of human hepatocellular carcinoma (HCC) cells remain unclear. Herein, we tested the hypothesis of the involvement of APPL1 in DAT-induced cytotoxicity in HCC HepG2 cells. We found that Lys 63 (K63)-linked polyubiquitination of APPL1 was significantly decreased whereas phosphorylation of APPL1 at serine residues remained unchanged in DAT-treated HepG2 cells. Compared with wild-type APPL1, overexpression of APPL1 K63R mutant dramatically increased cell apoptosis and mitigated cell survival, along with a reduction of phosphorylation of STAT3, Akt, and Erk1/2. In addition, DAT administration markedly reduced protein levels of intracellular TNF receptor-associated factor 6 (TRAF6). Genetic inhibition of TRAF6 decreased K63-linked polyubiquitination of APPL1. Moreover, the cytotoxicity impacts of DAT on HepG2 cells were greatly attenuated by overexpression of wild-type APPL1. Taken together, these results suggest that APPL1 polyubiquitination probably mediates the inhibitory effects of DAT on survival of HepG2 cells by modulating STAT3, Akt, and Erk1/2 pathways.

• Animal Bioscience
• /
• 제34권1호
• /
• pp.143-153
• /
• 2021

Objective: To explore the molecular mechanisms of fatty liver hemorrhagic syndrome (FLHS) in laying hens, an experiment was conducted to reveal the differences in histopathological observation and gene expression between FLHS group and normal group. Methods: We compared the histopathological difference using hematoxylin and eosin staining and proceeded with RNA sequencing of adipose tissue to search differentially expressed genes and enriched biological processes and pathways. Then we validated the mRNA expression levels by real-time polymerase chain reaction and quantified protein levels in the circulation by enzyme-linked immunosorbent assay. Results: We identified 100 differentially expressed transcripts corresponding to 66 genes (DEGs) were identified between FLHS-affected group and normal group. Seven DEGs were significantly enriched in the immune response process and lipid metabolic process, including phospholipase A2 group V, WAP kunitz and netrin domain containing 2, delta 4-desaturase sphingolipid 2, perilipin 3, interleukin-6 (IL-6), ciliary neurotrophic factor (CNTF), and suppressor of cytokine signaling 3 (SOCS3). And these genes could be the targets of immune response and be involved in metabolic homeostasis during the process of FLHS in laying hens. Based on functional categories of the DEGs, we further proposed a model to explain the etiology and pathogenesis of FLHS. IL-6 and SOCS3 mediate inflammatory responses and the satiety hormone of leptin, induce dysfunction of Jak-STAT signaling pathway, leading to insulin resistance and lipid metabolic disorders. Conversely, CNTF may reduce tissue destruction during inflammatory attacks and confer protection from inflammation-induced insulin resistance in FLHS chickens. Conclusion: These findings highlight the therapeutic implications of targeting the JAK-STAT pathway. Inhibition of IL6 and SOCS3 and facilitation of CNTF could serve as a favorable strategy to enhance insulin action and improve glucose homoeostasis, which are of importance for treating obesity-related disorders for chickens.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권10호
• /
• pp.5825-5831
• /
• 2013

Background/Objectives: Maintenance of cellular function in culture is vital for transfer and development following adoptive immunotherapy. Dual properties of IL-21 in activating T cells and reducing activation induced cell death led us to explore the mechanism of action of IL-21 enhanced proliferation and cytotoxic potential of CIK cells. Method: CIK cells cultured from PBMCs of healthy subjects were stimulated with IL-21 and cellular viability and cytotoxicity to K562 cells were measured. To elucidate the mechanism of action of IL-21, mRNA expression of cytotoxic factors was assessed by RT-PCR and protein expression of significantly important cytotoxic factors and cytokine secretion were determined through flow cytometry and ELISA. Western blotting was performed to check the involvement of the JAK/STAT pathway following stimulation. Results: We found that IL-21 did not enhance in vitro proliferation of CIK cells, but did increase the number of cells expressing the CD3+/CD56+ phenotype. Cytotoxic potential was increased with corresponding increase in perforin ($0.9831{\pm}0.1265$ to $0.7592{\pm}0.1457$), granzyme B ($0.4084{\pm}0.1589$ to $0.7319{\pm}0.1639$) and FasL ($0.4015{\pm}0.2842$ to $0.7381{\pm}0.2568$). Interferon gamma and TNF-alpha were noted to increase ($25.8{\pm}6.1ng/L$ to $56.0{\pm}2.3ng/L$; and $5.64{\pm}0.61{\mu}g/L$ to $15.14{\pm}0.93{\mu}g/L$, respectively) while no significant differences were observed in the expression of granzyme A, TNF-alpha and NKG2D, and NKG2D. We further affirmed that IL-21 signals through the STAT-3 and STAT-5b signaling pathway in the CIK cell pool. Conclusion: IL-21 enhances cytotoxic potential of CIK cells through increasing expression of perforin, granzyme B, IFN-gamma and TNF-alpha. The effect is brought about by the activation of STAT-3 and STAT-5b proteins.