Objective To explore the effects of miR-373 and Janus kinase 2/signal transducer and activator of transcription 6 (JAK2/STAT6) signaling pathways on the M2 polarization of tumor associated macrophages (TAM) in rectal cancer. Methods THP-1 cells were induced into M0/M1/M2 macrophages, M0 macrophages were cocultured with Caco-2 cells to obtain TAM, Flow cytometry was used to detect the expression of CD86 and CD206, Real-time quantitative qPCR and Western blot were used to detect miR-373, inducible nitric oxide synthase (iNOS), toll-like receptor 4 (TLR-4), interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), arginase 1 (Arg1), chitinase 3-like 1 (Ym1), resistin like α (Fizz1), IL-10 mRNA and protein levels. TAM were transfected and divided into overexpressing miR-373 group (miR-373-TAM) and control group (miR-NC-TAM), overexpressing miR-373+JAK2-TAM group (miR-373 combined with JAK2-TAM) and control group (miR-373 combined with NC-TAM), and then cocultured with Caco-2 cells. Flow cytometry was used to detect the expression of CD206 in TAM; Real-time quantitative PCR and Western blot were used to detect miR-373, Arg1, Ym1, Fizz1, IL-10, JAK2, STAT6 mRNA and protein levels in TAM; CCK-8 assay, colony formation assay, and Transwell assay were used to detect the proliferation, migration, and invasion ability of Caco-2 cells. Thirty nude mice were randomly divided into Caco-2 cells group, Caco-2 cells combined with miR-NC-TAM group, and Caco-2 cells combined with miR-373-TAM group, with 10 mice in each group. Rats in each group were subcutaneously injected with pure Caco-2 cells, Caco-2 cells combined with TAM, and Caco-2 cells combined with TAM overexpressing miR-373. After 4 weeks of cell inoculation, immunofluorescence staining was used to detect F4/80⁺CD206⁺cells level in tumor tissue; Real-time quantitative PCR and Western blot were used to detect miR-373, JAK2, STAT6, Arg1, Ym1, Fizz1, IL-10 mRNA and protein levels in tumor tissues. Results TAM tended to M2 polarization. After overexpression of miR-373, miR-373 level in TAM was increased, while Arg1, Ym1, Fizz1, IL-10, JAK2, STAT6 mRNA and protein levels were decreased, proliferation, migration, invasion ability of Caco-2 cells were decreased; Overexpression of JAK2 could partially reverse the effect of overexpression of miR-373 on the M2 polarization of TAM and proliferation, migration, invasion ability of Caco-2 cells. TAM could promote tumor growth; Overexpression of miR-373 could inhibit tumor growth and inhibit M2 polarization of TAM. Conclusion miR-373 could inhibit M2 polarization of TAM in rectal cancer, and miR-373 might inhibit proliferation and metastasis of rectal cancer cells by regulating the JAK2/STAT6 pathway.
MicroRNAs/metabolism* ; Humans ; STAT6 Transcription Factor/genetics* ; Signal Transduction/genetics* ; Animals ; Janus Kinase 2/genetics* ; Mice ; Tumor-Associated Macrophages/metabolism* ; Rectal Neoplasms/pathology* ; Caco-2 Cells ; Mice, Nude ; THP-1 Cells ; Mice, Inbred BALB C ; Cell Polarity ; Male

Objective To investigate the regulatory effect of suppressor of cytokine signaling 1 (SOCS1) on the proliferation and apoptosis of myelodysplastic syndrome (MDS) cells SKM-1 and its potential mechanisms. Methods SOCS1 was overexpressed in SKM-1 cells by transfection with exogenous SOCS1-overexpressing plasmid. Cell viability, cell cycle and apoptosis were analyzed with CCK-8 and flow cytometry assays, respectively. Western blot was used to evaluate the expression of proteins related to the Janus kinase 2/signal transducer and activator of transcription (JAK2/STAT) signaling pathway. Additionally, a NOD/SCID mouse model of MDS was established to record mouse body weight and survival time, assessing the impact of the SOCS1 gene on the growth of SKM-1 cells in vivo. Results Transfection of the SOCS1-overexpressing plasmid significantly increased the mRNA and protein expression levels of SOCS1 in the MDS cell line SKM-1. Overexpression of SOCS1 remarkably reduced cell viability, inhibited cell proliferation, and promoted apoptosis of SKM-1 cells, which also decreased the expression of phosphorylated-JAK2 (p-JAK2), phosphorylated-STAT3 (p-STAT3), and p-STAT5 proteins. Furthermore, in vivo experiment results showed that the body weight and survival time of mice in the SOCS1 overexpression group were significantly better than those in the MDS model group, and the number of CD45⁺ SKM-1 cells in the peripheral blood was significantly lower than that in the MDS model group, indicating that SOCS1 overexpression could inhibit the activity of SKM-1 cells in mice. Western blot results verified the protein expression level of SOCS1 in the bone marrow of mice in the SOCS1 overexpression group was significantly higher than that in the MDS model group, while the protein expression levels of p-JAK2, p-STAT3, and p-STAT5 were significantly lower than those in the MDS model group. Conclusion SOCS1 inhibits the proliferation of MDS cell line SKM-1 and promotes its apoptosis by negatively regulating the JAK2/STAT signaling pathway, making it a potential therapeutic target for myelodysplastic syndromes.
Animals ; Humans ; Mice ; Apoptosis ; Body Weight ; Bone Marrow/metabolism* ; Janus Kinase 2/metabolism* ; Mice, Inbred NOD ; Mice, SCID ; Myelodysplastic Syndromes/metabolism* ; Phosphorylation ; STAT3 Transcription Factor/metabolism* ; STAT5 Transcription Factor/metabolism* ; Suppressor of Cytokine Signaling 1 Protein/metabolism* ; Cell Proliferation

OBJECTIVE: This study aimed to investigate the effects of caprylic acid (C8:0) on lipid metabolism and inflammation, and examine the mechanisms underlying these effects in mice and cells. METHODS: Fifty-six 6-week-old male C57BL/6J mice were randomly allocated to four groups fed a high-fat diet (HFD) without or with 2% C8:0, palmitic acid (C16:0) or eicosapentaenoic acid (EPA). RAW246.7 cells were randomly divided into five groups: normal, lipopolysaccharide (LPS), LPS+C8:0, LPS+EPA and LPS+cAMP. The serum lipid profiles, inflammatory biomolecules, and ABCA1 and JAK2/STAT3 mRNA and protein expression were measured. RESULTS: C8:0 decreased TC and LDL-C, and increased the HDL-C/LDL-C ratio after injection of LPS. Without LPS, it decreased TC in mice ( P < 0.05). Moreover, C8:0 decreased the inflammatory response after LPS treatment in both mice and cells ( P < 0.05). Mechanistic investigations in C57BL/6J mouse aortas after injection of LPS indicated that C8:0 resulted in higher ABCA1 and JAK2/STAT3 expression than that with HFD, C16:0 and EPA, and resulted in lower TNF-α, NF-κB mRNA expression than that with HFD ( P < 0.05). In RAW 264.7 cells, C8:0 resulted in lower expression of pNF-κBP65 than that in the LPS group, and higher protein expression of ABCA1, p-JAK2 and p-STAT3 than that in the LPS and LPS+cAMP groups ( P < 0.05). CONCLUSION Our studies demonstrated that C8:0 may play an important role in lipid metabolism and the inflammatory response, and the mechanism may be associated with ABCA1 and the p-JAK2/p-STAT3 signaling pathway.
ATP Binding Cassette Transporter 1/immunology* ; Animals ; Caprylates/chemistry* ; Cholesterol/metabolism* ; Diet, High-Fat/adverse effects* ; Humans ; Inflammation/metabolism* ; Janus Kinase 2/immunology* ; Lipid Metabolism/drug effects* ; Macrophages/immunology* ; Male ; Mice ; Mice, Inbred C57BL ; RAW 264.7 Cells ; STAT3 Transcription Factor/immunology* ; Signal Transduction

The aim of this study was to investigate the relationship between the effects of different doses of X-rays on DNA damage and JAK/STAT signaling pathway activation in A549 cells. The A549 cells were radiated with X-rays at doses of 2, 4, and 8 Gy. The proliferation of A549 cells was detected by CCK8 method. The content of interleukin 6 (IL-6) in culture medium at different time points after irradiation was detected by enzyme-linked immunoassay, and the expression levels of IL-6 receptor (IL-6R) and p53 binding protein 1 (53BP1) were detected by immunofluorescent staining. The expression levels of JAK2, p-JAK2, STAT3 and p-STAT3 were detected by Western blot. The results showed that, compared with the control group, X-ray irradiation reduced the cellular proliferation, up-regulated the expression of 53BP1, increased the IL-6 content in the medium supernatant, and up-regulated the protein expression levels of IL-6R, JAK2, p-JAK2, STAT3, and p-STAT3. The above effects of X-ray irradiation were dose-dependent. These results suggest that the mechanism by which X-rays cause DNA damage in A549 cells may involve activation of the JAK/STAT signaling pathway.
A549 Cells ; DNA Damage ; radiation effects ; Humans ; Janus Kinase 2 ; metabolism ; Receptors, Interleukin-6 ; metabolism ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; Tumor Suppressor p53-Binding Protein 1 ; metabolism ; X-Rays

The epithelial cytokine response, associated with reactive oxygen species (ROS), is important in Helicobacter pylori (H. pylori)-induced inflammation. H. pylori induces the production of ROS, which may be involved in the activation of mitogen-activated protein kinases (MAPK), janus kinase/signal transducers and activators of transcription (Jak/Stat), and oxidant-sensitive transcription factor, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB), and thus, expression of interleukin-8 (IL-8) in gastric epithelial cells. alpha-lipoic acid, a naturally occurring thiol compound, is a potential antioxidant. It shows beneficial effects in treatment of oxidant-associated diseases including diabetes. The present study is purposed to investigate whether alpha-lipoic acid inhibits expression of inflammatory cytokine IL-8 by suppressing activation of MAPK, Jak/Stat, and NF-kappaB in H. pylori-infected gastric epithelial cells. Gastric epithelial AGS cells were pretreated with or without alpha-lipoic acid for 2 h and infected with H. pylori in a Korean isolate (HP99) at a ratio of 300:1. IL-8 mRNA expression was analyzed by RT-PCR analysis. IL-8 levels in the medium were determined by enzyme-linked immunosorbent assay. NF-kappaB-DNA binding activity was determined by electrophoretic mobility shift assay. Phospho-specific and total forms of MAPK and Jak/Stat were assessed by Western blot analysis. ROS levels were determined using dichlorofluorescein fluorescence. As a result, H. pylori induced increases in ROS levels, mRNA, and protein levels of IL-8, as well as the activation of MAPK [extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun NH2-terminal kinase 1/2 (JNK1/2), p38], Jak/Stat (Jak1/2, Stat3), and NF-kappaB in AGS cells, which was inhibited by alpha-lipoic acid. In conclusion, alpha-lipoic acid may be beneficial for prevention and/or treatment of H. pylori infection-associated gastric inflammation.
Enzyme-Linked Immunosorbent Assay ; Epithelial Cells/metabolism ; Gastric Mucosa/*drug effects/metabolism/microbiology ; Gene Expression Regulation, Bacterial ; Helicobacter Infections/immunology/*metabolism ; Helicobacter pylori/drug effects/*pathogenicity ; Humans ; Interleukin-8/genetics/*metabolism ; JNK Mitogen-Activated Protein Kinases ; Janus Kinase 1 ; Mitogen-Activated Protein Kinases/*biosynthesis ; NF-kappa B/*metabolism ; RNA, Messenger/isolation & purification/metabolism ; Reactive Oxygen Species/metabolism ; STAT3 Transcription Factor ; Stomach/metabolism/*microbiology ; Thioctic Acid/*pharmacology

Specific gene expressions of host cells by spontaneous STAT6 phosphorylation are major strategy for the survival of intracellular Toxoplasma gondii against parasiticidal events through STAT1 phosphorylation by infection provoked IFN-γ. We determined the effects of small molecules of tyrosine kinase inhibitors (TKIs) on the growth of T. gondii and on the relationship with STAT1 and STAT6 phosphorylation in ARPE-19 cells. We counted the number of T. gondii RH tachyzoites per parasitophorous vacuolar membrane (PVM) after treatment with TKIs at 12-hr intervals for 72 hr. The change of STAT6 phosphorylation was assessed via western blot and immunofluorescence assay. Among the tested TKIs, Afatinib (pan ErbB/EGFR inhibitor, 5 µM) inhibited 98.0% of the growth of T. gondii, which was comparable to pyrimethamine (5 µM) at 96.9% and followed by Erlotinib (ErbB1/EGFR inhibitor, 20 µM) at 33.8% and Sunitinib (PDGFR or c-Kit inhibitor, 10 µM) at 21.3%. In the early stage of the infection (2, 4, and 8 hr after T. gondii challenge), Afatinib inhibited the phosphorylation of STAT6 in western blot and immunofluorescence assay. Both JAK1 and JAK3, the upper hierarchical kinases of cytokine signaling, were strongly phosphorylated at 2 hr and then disappeared entirely after 4 hr. Some TKIs, especially the EGFR inhibitors, might play an important role in the inhibition of intracellular replication of T. gondii through the inhibition of the direct phosphorylation of STAT6 by T. gondii.
Antiparasitic Agents/pharmacology ; Blotting, Western ; Cell Line ; Enzyme Activation/drug effects ; Fluorescent Antibody Technique ; Humans ; Janus Kinase 1/metabolism ; Janus Kinase 3/metabolism ; Phosphorylation/drug effects ; Quinazolines/*pharmacology ; STAT6 Transcription Factor/*metabolism ; Signal Transduction/*drug effects ; Toxoplasma/*drug effects/physiology ; Toxoplasmosis/physiopathology

OBJECTIVETo investigate the dual role of daphnetin in suppressing high mobility group box-1 protein (HMGB1) release and blocking HMGB1-induced inflammatory response.

METHODSMurine macrophage RAW264.7 cells were cultured in the presence of daphnetin, lipopolysaccharide (LPS), or both. HMGB1 release from the cells was determined using ELISA, and phosphorylations of JAK1/2 and of STAT1 were detected by Western blotting. Human monocytic THP-1 cells exposed to daphnetin, rhHMGB1, or both were examined for NO production using a NO detection kit, for the release of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and prostaglandin E2 (PGE2) using ELISA, and for expressions of iNOS, COX-2 and phosphorylated p38, ERK, and JNK with Western blotting.

RESULTSDaphnetin dose-dependently reduced the release of HMGB1 in RAW264.7 cells and suppressed rhHMGB1-induced iNOS and COX-2 expressions and release of TNF-α, IL-6, PGE2, and NO in THP-1 cells. Western blotting revealed that daphnetin significantly down-regulated the phosphorylations of JAK-STAT1 pathway in LPS-stimulated RAW264.7 cells but did not suppress the phosphorylations of MAPKs signaling pathway induced by rhHMGB1 in THP-1 cells.

CONCLUSIONDaphnetin can reduce the release of HMGB1 and suppress HMGB1-induced inflammatory response. In RAW264.7 cells, daphnetin inhibited LPS induced HMGB1 release is at least partly mediated by suppressing JAK-STAT1 signaling pathway activation.

Animals ; Cell Line ; Cyclooxygenase 2 ; metabolism ; Dinoprostone ; metabolism ; HMGB1 Protein ; metabolism ; Humans ; Inflammation ; metabolism ; Interleukin-6 ; metabolism ; Janus Kinase 1 ; metabolism ; Lipopolysaccharides ; Macrophages ; drug effects ; Mice ; Monocytes ; drug effects ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type II ; metabolism ; RAW 264.7 Cells ; STAT1 Transcription Factor ; metabolism ; Signal Transduction ; drug effects ; Tumor Necrosis Factor-alpha ; metabolism ; Umbelliferones ; pharmacology

Helicobacter pylori (H. pylori) induces the activation of nuclear factor-kB (NF-kappaB) and cytokine expression in gastric epithelial cells. The Janus kinase/signal transducers and activators of transcription (Jak/Stat) cascade is the inflammatory signaling in various cells. The purpose of the present study is to determine whether H. pylori-induced activation of NF-kappaB and the expression of interleukin-8 (IL-8) are mediated by the activation of Jak1/Stat3 in gastric epithelial (AGS) cells. Thus, gastric epithelial AGS cells were infected with H. pylori in Korean isolates (HP99) at bacterium/cell ratio of 300:1, and the level of IL-8 in the medium was determined by enzyme-linked immonosorbent assay. Phospho-specific and total forms of Jak1/Stat3 and IkappaBalpha were assessed by Western blot analysis, and NF-kappaB activation was determined by electrophoretic mobility shift assay. The results showed that H. pylori induced the activation of Jak1/Stat3 and IL-8 production, which was inhibited by a Jak/Stat3 specific inhibitor AG490 in AGS cells in a dose-dependent manner. H. pylori-induced activation of NF-kappaB, determined by phosphorylation of IkappaBalpha and NF-kappaB-DNA binding activity, were inhibited by AG490. In conclusion, Jak1/Stat3 activation may mediate the activation of NF-kappaB and the expression of IL-8 in H. pylori-infected AGS cells. Inhibition of Jak1/Stat3 may be beneficial for the treatment of H. pylori-induced gastric inflammation, since the activation of NF-kappaB is inhibited and inflammatory cytokine expression is suppressed.
Blotting, Western ; DNA, Bacterial/analysis/genetics ; Epithelial Cells/metabolism ; Gastric Mucosa/drug effects/*immunology/microbiology ; Gene Expression Regulation/drug effects/*immunology ; Gene Expression Regulation, Bacterial ; Helicobacter Infections/immunology/*metabolism ; Helicobacter pylori/genetics/pathogenicity/*physiology ; Humans ; Interleukin-8/genetics/*metabolism ; Janus Kinase 1 ; NF-kappa B/biosynthesis/*metabolism ; Phosphorylation ; RNA, Messenger/metabolism ; STAT3 Transcription Factor ; Signal Transduction/genetics

Helicobacter pylori (H. pylori) induces the activation of nuclear factor-kB (NF-kappaB) and cytokine expression in gastric epithelial cells. The Janus kinase/signal transducers and activators of transcription (Jak/Stat) cascade is the inflammatory signaling in various cells. The purpose of the present study is to determine whether H. pylori-induced activation of NF-kappaB and the expression of interleukin-8 (IL-8) are mediated by the activation of Jak1/Stat3 in gastric epithelial (AGS) cells. Thus, gastric epithelial AGS cells were infected with H. pylori in Korean isolates (HP99) at bacterium/cell ratio of 300:1, and the level of IL-8 in the medium was determined by enzyme-linked immonosorbent assay. Phospho-specific and total forms of Jak1/Stat3 and IkappaBalpha were assessed by Western blot analysis, and NF-kappaB activation was determined by electrophoretic mobility shift assay. The results showed that H. pylori induced the activation of Jak1/Stat3 and IL-8 production, which was inhibited by a Jak/Stat3 specific inhibitor AG490 in AGS cells in a dose-dependent manner. H. pylori-induced activation of NF-kappaB, determined by phosphorylation of IkappaBalpha and NF-kappaB-DNA binding activity, were inhibited by AG490. In conclusion, Jak1/Stat3 activation may mediate the activation of NF-kappaB and the expression of IL-8 in H. pylori-infected AGS cells. Inhibition of Jak1/Stat3 may be beneficial for the treatment of H. pylori-induced gastric inflammation, since the activation of NF-kappaB is inhibited and inflammatory cytokine expression is suppressed.
Blotting, Western ; DNA, Bacterial/analysis/genetics ; Epithelial Cells/metabolism ; Gastric Mucosa/drug effects/*immunology/microbiology ; Gene Expression Regulation/drug effects/*immunology ; Gene Expression Regulation, Bacterial ; Helicobacter Infections/immunology/*metabolism ; Helicobacter pylori/genetics/pathogenicity/*physiology ; Humans ; Interleukin-8/genetics/*metabolism ; Janus Kinase 1 ; NF-kappa B/biosynthesis/*metabolism ; Phosphorylation ; RNA, Messenger/metabolism ; STAT3 Transcription Factor ; Signal Transduction/genetics

BACKGROUNDSuppressor of cytokine signaling (SOCS) proteins are inhibitors of cytokine signaling pathway involved in negative feedback loops. Although SOCS1 is an important intracellular suppressor of apoptosis in a variety of cell types, its role in cytokine-induced pancreatic β-cell apoptosis remains unclear. The present study investigated potential effects of SOCS1 on the cytokine-induced pancreatic β-cell apoptosis.

METHODSAfter successfully transfected with SOCS1/pEGFP-C1 or pEGFP-C1 plasmids to overexpress SOCS1, RINm5F (rat insulinoma cell line) cells were exposed to cytokines, interferon (IFN)-γ alone, IFN-γ+interleukin (IL)-1β, IFN-β+IL-1β+tumor necrosis factor (TNF)-α respectively. Pancreatic β-cell apoptosis was assessed by using MTT, FACS, and caspase-3 activity assays. Protein phosphorylation of Janus kinase 2 (JAK2) and signal transducers and activators of transcription 1 (STAT1) were verified by Western blotting and mRNA expression of inducible nitric oxide synthase (iNOS), NF-κB and Fas were analyzed by RT-PCR.

RESULTSOverexpression of SOCS1 in RINm5F cells was shown to attenuate IFN-γ alone, IFN-γ+IL-1β and IFN-γ+TNF-α+IL-1β mediated apoptosis. Phosphorylation of JAK2 and STAT1 significantly decreased in RINm5F cells which overexpressed SOCS1 protein. Overexpression of SOCS1 significantly suppressed cytokine-induced iNOS mRNA levels.

CONCLUSIONOverexpression of SOCS1 protects pancreatic islets from cytokine-induced cell apoptosis via the JAK2/STAT1 pathway.

Animals ; Apoptosis ; drug effects ; genetics ; Blotting, Western ; Cell Line ; Cytokines ; pharmacology ; Interferon-gamma ; pharmacology ; Interleukin-1 ; pharmacology ; Islets of Langerhans ; cytology ; drug effects ; Janus Kinase 2 ; metabolism ; Phosphorylation ; drug effects ; Rats ; Reverse Transcriptase Polymerase Chain Reaction ; STAT1 Transcription Factor ; genetics ; metabolism ; Signal Transduction ; drug effects ; Suppressor of Cytokine Signaling 1 Protein ; Suppressor of Cytokine Signaling Proteins ; genetics ; metabolism ; Tumor Necrosis Factor-alpha ; pharmacology