• Journal of Life Science
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• v.30 no.10
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• pp.867-876
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• 2020

This study investigated the repair of UVB-induced cell damage by magnolol. We performed a drug-repurposing screen, and, in the STAT3 reporter gene assay, magnolol was identified as a suppressor of STAT3 that improves the cell viability of HDF cells. HDF cells treated with IL-6, UVB, and IFNγ showed the highest expression of Jak2 and phosphorylated STAT3 (p-STAT3), and magnolol was able to decrease the expression of Jak2 and p-STAT3 in UVB-induced cells. Moreover, UVB-damaged cell growth increased significantly in correlation with both reactivation and with magnolol in a dose-dependent manner. Compared with AG490 (a Jak2 inhibitor) treatment of UVB-treated HDF cells, cell proliferation increased significantly. We confirmed that AG490 and magnolol reduced TNF-α concentrations, and Western blotting (protein level) showed decreases in Jak2 and p-STAT3 expression in only the magnolol-treated cells. The expression of Jak2, p-STAT3, and SOCS3 also increased only after treatment with magnolol. Cells were treated with magnolol and ML385 (an NRF2 inhibitor), and these secondary metabolites reduced cell proliferation and NRF2 expression. The amount of MMP9 was also increased by cotreatment with magnolol and ML385. Collectively, these results demonstrate the potential of magnolol for repairing cells after UVB-induced damage by regulating the expression of NRF2, SOCS3, Jak2, and STAT3.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.189-193
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• 2021

Jak-STAT pathway is required for embryogenesis, female gametogenesis, cytokine-mediated neuroprotection, diabetes, obesity, cancer, stem cell, and various tissues. The noncanonical role of Jak-STAT in mitochondria function was supported by the detection of STAT protein in mitochondria, however, several studies show that STAT protein is detected in the endoplasmic reticulum (ER), and not in mitochondria. STAT protein may alter mitochondria function without entering mitochondria, this involves regulation of fission and fusion proteins to change mitochondria morphology. However, how changes in mitochondria morphology lead to changes in mitochondria metabolism needs further investigation.

• Journal of Korean Neurosurgical Society
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• v.63 no.4
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• pp.444-454
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• 2020

Objective : Glioblastoma multiforme (GBM) is the most aggressive for of brain tumor and treatment often fails due to the invasion of tumor cells into neighboring healthy brain tissues. Activation of the Janus kinase-signal transducer and activator of transcription (JAK/STAT) signaling pathway is essential for normal cellular function including angiogenesis, and has been proposed to have a pivotal role in glioma invasion. This study aimed to determine the dose-dependent effects of ruxolitinib, an inhibitor of JAK, on the interferon (IFN)-I/IFN-α/IFN-β receptor/STAT and IFN-γ/IFN-γ receptor/STAT1 axes of the IFN-receptor-dependent JAK/STAT signaling pathway in glioblastoma invasion and tumorigenesis in U87 glioblastoma tumor spheroids. Methods : We administered three different doses of ruxolitinib (50, 100, and 200 nM) to human U87 glioblastoma spheroids and analyzed the gene expression profiles of IFNs receptors from the JAK/STAT pathway. To evaluate activation of this pathway, we quantified the phosphorylation of JAK and STAT proteins using Western blotting. Results : Quantitative real-time polymerase chain reaction analysis demonstrated that ruxolitinib led to upregulated of the IFN-α and IFN-γ while no change on the hypoxia-inducible factor-1α and vascular endothelial growth factor expression levels. Additionally, we showed that ruxolitinib inhibited phosphorylation of JAK/STAT proteins. The inhibition of IFNs dependent JAK/STAT signaling by ruxolitinib leads to decreases of the U87 cells invasiveness and tumorigenesis. We demonstrate that ruxolitinib may inhibit glioma invasion and tumorigenesis through inhibition of the IFN-induced JAK/STAT signaling pathway. Conclusion : Collectively, our results revealed that ruxolitinib may have therapeutic potential in glioblastomas, possibly by JAK/STAT signaling triggered by IFN-α and IFN-γ.

• Molecules and Cells
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• v.23 no.1
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• pp.94-99
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• 2007

Suppressors of cytokine signaling (SOCS) family members are negative feedback regulators of the Jak/Stat pathway, which is an essential inflammatory signaling pathway. We investigated expression of eight members of the SOCS family in rat astrocytes, using two inflammatory stimulants, PMA and IFN-${\gamma}$. Only a few SOCS genes were induced by both stimulants, and we detected an increase in SOCS5 protein with PMA. PMA activated the Jnk, Erk, p38, and Jak/Stat signal pathways. In addition, it increased the level of activated-Stat3 resulting from tyrosine phosphorylation. A gel-shift assay showed that a protein in nuclear extracts from PMA-treated cells was able to bind to Stat binding elements. These results suggest that activated Stat3 binds to SOCS promoters and leads to their transcriptional induction.

• Biomolecules & Therapeutics
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• v.19 no.2
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• pp.141-148
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• 2011

Osteoclasts are bone-resorbing cells of monocyte/macrophage origin and are culprits of bone destruction associated with osteoporosis, rheumatoid arthritis, and cancer bone metastasis. Recent advances in osteoclast biology revealed central roles of various cytokines in regulating osteoclastogenesis both in vitro and in vivo. However, exact underlying mechanisms including signaling pathways downstream of receptor ligation are still under pursuit. In the present review, the role of Jak/STAT proteins and their regulators will be discussed in connection with osteoclastogenesis, since growing evidence indicates that a number of cytokines and growth factors utilizing Jak/STAT signaling pathways affect osteoclastogenesis. A better understanding on the role of Jak/STAT pathways in osteoclast differentiation will not only strengthen our knowledge on osteoclast biology but also provide invaluable insights into the development of anti-resorptive strategies for treating bone-lytic diseases.

• Molecules and Cells
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• v.38 no.5
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• pp.441-451
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• 2015

Recognition of cytosolic DNA initiates a series of innate immune responses by inducing IFN-I production and subsequent triggering JAK1-STAT1 signaling which plays critical roles in the pathogenesis of infection, inflammation and autoimmune diseases through promoting B cell activation and antibody responses. The stimulator of interferon genes protein (STING) has been demonstrated to be a critical hub of type I IFN induction in cytosolic DNA-sensing pathways. However, it still remains unknown whether cytosolic DNA can directly activate the JAK1-STAT1 signaling or not. And the role of STING is also unclear in this response. In the present study, we found that dsDNA directly triggered the JAK1-STAT1 signaling by inducing phosphorylation of the Lyn kinase. Moreover, this response is not dependent on type I IFN receptors. Interestingly, STING could inhibit dsDNA-triggered activation of JAK1-STAT1 signaling by inducing SHP-1 and SHP-2 phosphorylation. In addition, compared with normal B cells, the expression of STING was significantly lower and the phosphorylation level of JAK1 was significantly higher in B cells from MRL/lpr lupus-prone mice, highlighting the close association between STING low-expression and JAK1-STAT1 signaling activation in B cells in autoimmune diseases. Our data provide a molecular insight into the novel role of STING in dsDNA-mediated inflammatory disorders.

• Biomolecules & Therapeutics
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• v.30 no.1
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• pp.72-79
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• 2022

Licochalcone H (LCH) is a phenolic compound synthetically derived from licochalcone C (LCC) that exerts anticancer activity. In this study, we investigated the anticancer activity of LCH in human skin cancer A375 and A431 cells. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) cell viability assay was used to evaluate the antiproliferative activity of LCH. Cell cycle distribution and the induction of apoptosis were analyzed by flow cytometry. Western blotting assays were performed to detect the levels of proteins involved in cell cycle progression, apoptosis, and the JAK2/STAT3 signaling pathway. LCH inhibited the growth of cells in dose- and time-dependent manners. The annexin V/propidium iodide double staining assay revealed that LCH induced apoptosis, and the LCH-induced apoptosis was accompanied by cell cycle arrest in the G1 phase. Western blot analysis showed that the phosphorylation of JAK2 and STAT3 was decreased by treatment with LCH. The inhibition of the JAK2/STAT3 signaling pathway by pharmacological inhibitors against JAK2/STAT3 (cryptotanshinone (CTS) and S3I-201) simulated the antiproliferative effect of LCH suggesting that LCH induced apoptosis by modulating JAK2/STAT3 signaling.

• Journal of Acupuncture Research
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• v.29 no.1
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• pp.47-59
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• 2012

목적 : 이 연구는 봉독이 사람의 난소암 세포인 SKOV3와 PA-1에서 death receptor의 발현을 높여 세포자멸사를 촉진함으로써 암세포의 성장을 억제하는지 밝히고자 하였다. 방법 : 난소암의 세포자멸사의 관찰에는 DAPI, TUNEL staining assay를 시행하였으며, 세포자멸사 조절 단백질의 변동 관찰에는 western blot analysis를 시행하였고, 난소암 세포에서 death receptor의 변화를 관찰하기 위해 RT-PCR analysis를 시행하였다. 결과 : 1. DAPI, TUNEL staining assay 결과, 봉독은 투여량에 따라 세포자멸사의 유도를 통해 SKOV3와 PA-1 난소암세포의 증식을 억제하였고, 세포자멸사와 동반하여 DR4와 DR6의 발현이 두 암세포 모두에서 증가하였고, DR3의 출현은 PA-1 세포에서 증가하였다. 2. Death Receptor의 발현 증가에 따라 caspase-3, 8, 9 and Bax를 포함하는 세포자멸사 촉진 단백질의 발현이 동반하여 상승하였고 JAK2, STAT3의 인산화와 Bcl-2의 발현은 억제되었다. 3. siRNA 처리 시 봉독에 의한 DR3, DR4, DR6 발현증가와 STAT3의 활성억제가 역전되었다. 결론 : 이러한 결과는 봉독이 난소암 세포에서 DR3, DR4, DR6의 증가와 JAK2/STAT3 pathway의 억제를 통하여 세포자멸사를 유발한다는 것을 시사하며, 난소암의 예방과 치료에 효과적으로 활용될 수 있을 것으로 기대된다.

• Journal of dental hygiene science
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• v.17 no.1
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• pp.81-86
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• 2017

Bacterial infection and smoking are an important risk factors involved in the development and progression of periodontitis. However, the signaling mechanism underlying the host immune response is not fully understood in periodontal lesions. In this study, we determined the expression of janus kinase (JAK)/signal transducer and activator of transcription (STAT) on Porphyromonas gingivalis lipopolysaccharide (LPS)- and nicotine-induced cytotoxicity and the production of inflammatory mediators, using osteoblasts. The cells were cultured with 5 mM nicotine in the presence of $1{\mu}g/ml$ LPS. Cell viability was determined using MTT assay. The role of JAK on inflammatory mediator expression and production, and the regulatory mechanisms involved were assessed via enzyme-linked immunosorbent assay, reverse transcription-polymerase chain reaction, and Western blot analysis. LPS- and nicotine synergistically induced the production of cyclooxgenase-2 (COX-2) and prostaglandin $E_2$ ($PGE_2$) and increased the protein expression of JAK/STAT. Treatment with an JAK inhibitor blocked the production of COX-2 and $PGE_2$ as well as the expression of pro-inflammatory cytokines, such as tumor necrosis factor-${\alpha}$, interleukin-$1{\beta}$ ($IL-1{\beta}$), and IL-6 in LPS- and nicotine-stimulated osteoblasts. These results suggest that JAK/STAT is closely related to the LPS- and nicotine-induced inflammatory effects and is likely to regulate the immune response in periodontal disease associated with dental plaque and smoking.

• Journal of Life Science
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• v.32 no.2
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• pp.125-134
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• 2022

This study investigated whether or not the major bioactive compounds of Noni (Morinda citrifolia) are involved in anti-inflammatory activity through the JAK/STAT upper signaling pathway in RAW 264.7 cells. The experimental results show that the M. citrifolia ethyl acetate fraction (Mc-EtOAc) obtained by sequential fractionation with organic solvents from the plant's dried fruits exhibits the highest antioxidant activity. In addition, the cytoprotective effects of Mc-EtOAc against H₂O₂-induced oxidative stress in the RAW 264.7 cells suppressed cytotoxicity in a dose-dependent manner. The group pretreated with Mc-EtOAc at a concentration of 240 ㎍/ml showed higher cell viability of 84.5%, compared to 71.6% in the LPS-treated group, and LPS-induced NO production decreased to half the amount in the positive control group. Mc-EtOAc treatment also led to a significant dose-dependent reduction in iNOS expression. Although COX-2 expression was increased by 300% following LPS induction, it was significantly decreased in a dose-dependent manner by pretreatment with Mc-EtOAc at concentrations of 120 and 240 ㎍/ml. An inhibition of the mRNA expression of pro-inflammatory cytokines IL-1β and TNF-α was observed. The investigation also revealed that the phosphorylation levels of pJAK1 and pSTAT3 in LPS-induced RAW 264.7 cells were significantly reduced by Mc-EtOAc treatment.