IFN-γ–inducible antiviral responses require ULK1-mediated activation of MLK3 and ERK5

It is well established that activation of the transcription factor signal transducer and activator of transcription 1 (STAT1) is required for the interferon-γ (IFN-γ)–mediated antiviral response. Here, we found that IFN-γ receptor stimulation also activated Unc-51–like kinase 1 (ULK1), an initiator of Beclin-1–mediated autophagy. Furthermore, the interaction between ULK1 and the mitogen-activated protein kinase kinase kinase MLK3 (mixed lineage kinase 3) was necessary for MLK3 phosphorylation and downstream activation of the kinase ERK5. This autophagy-independent activity of ULK1 promoted the transcription of key antiviral IFN-stimulated genes (ISGs) and was essential for IFN-γ–dependent antiviral effects. These findings define a previously unknown IFN-γ pathway that appears to be a key element of the antiviral response.

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Phloretin alleviates dinitrochlorobenzene-induced dermatitis in BALB/c mice

International Journal of Immunopathology and Pharmacology ◽

10.1177/2058738420929442 ◽

2020 ◽

Vol 34 ◽

pp. 205873842092944

Author(s):

Chieh-Shan Wu ◽

Shih-Chao Lin ◽

Shiming Li ◽

Yu-Chih Chiang ◽

Nicole Bracci ◽

...

Keyword(s):

Mouse Model ◽

Serum Levels ◽

Interferon Γ ◽

Chronic Inflammatory Disease ◽

Mitogen Activated Protein Kinase ◽

Normal Ranges ◽

Mitogen Activated Protein ◽

Ifn Γ ◽

Allergic Contact

Atopic dermatitis (AD) is a chronic inflammatory disease of the skin that substantially affects a patient’s quality of life. While steroids are the most common therapy used to temporally alleviate the symptoms of AD, effective and nontoxic alternatives are urgently needed. In this study, we utilized a natural, plant-derived phenolic compound, phloretin, to treat allergic contact dermatitis (ACD) on the dorsal skin of mice. In addition, the effectiveness of phloretin was evaluated using a mouse model of ACD triggered by 2,4-dinitrochlorobenzene (DNCB). In our experimental setting, phloretin was orally administered to BALB/c mice for 21 consecutive days, and then, the lesions were examined histologically. Our data revealed that phloretin reduced the process of epidermal thickening and decreased the infiltration of mast cells into the lesion regions, subsequently reducing the levels of histamine and the pro-inflammatory cytokines interleukin (IL)-6, IL-4, thymic stromal lymphopoietin (TSLP), interferon-γ (IFN-γ) and IL-17A in the serum. These changes were associated with lower serum levels after phloretin treatment. In addition, we observed that the mitogen-activated protein kinase (MAPK) and NF-κB pathways in the dermal tissues of the phloretin-treated rodents were suppressed compared to those in the AD-like skin regions. Furthermore, phloretin appeared to limit the overproliferation of splenocytes in response to DNCB stimulation, reducing the number of IFN-γ-, IL-4-, and IL-17A-producing CD4+ T cells in the spleen back to their normal ranges. Taken together, we discovered a new therapeutic role of phloretin using a mouse model of DNCB-induced ACD, as shown by the alleviated AD-like symptoms and the reversed immunopathological effects. Therefore, we believe that phloretin has the potential to be utilized as an alternative therapeutic agent for treating AD.

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Ras-Related C3 Botulinum Toxin Substrate 1 Combining With the Mixed Lineage Kinase 3- Mitogen-Activated Protein Kinase 7- c-Jun N-Terminal Kinase Signaling Module Accelerates Diabetic Nephropathy

Frontiers in Physiology ◽

10.3389/fphys.2021.679166 ◽

2021 ◽

Vol 12 ◽

Author(s):

Changjiang Ying ◽

Jiao Dai ◽

Gaoxia Fan ◽

Zhongyuan Zhou ◽

Tian Gan ◽

...

Keyword(s):

Diabetic Nephropathy ◽

Botulinum Toxin ◽

Protein Kinase ◽

Molecular Mechanisms ◽

Caspase 3 ◽

Mitogen Activated Protein Kinase ◽

Jnk Signaling ◽

Mixed Lineage Kinase ◽

Mitogen Activated Protein ◽

Mixed Lineage Kinase 3

Ras-related C3 botulinum toxin substrate 1 (RAC1) activation plays a vital role in diabetic nephropathy (DN), but the exact mechanism remains unclear. In this study, we attempted to elucidate the precise mechanism of how RAC1 aggravates DN through cellular and animal experiments. In this study, DN was induced in mice by intraperitoneal injection of streptozotocin (STZ, 150mg/kg), and the RAC1 inhibitor NSC23766 was administered by tail vein injection. Biochemical indicators, cell proliferation and apoptosis, and morphological changes in the kidney were detected. The expression of phosphorylated c-Jun N-terminal kinase (p-JNK), nuclear factor-κB (NF-κB), and cleaved caspase-3 and the interaction between RAC1 and the mixed lineage kinase 3 (MLK3)-mitogen-activated protein kinase 7 (MKK7)-JNK signaling module were determined. Furthermore, the colocalization and direct co-interaction of RAC1 and MLK3 were confirmed. Our results showed that RAC1 accelerates renal damage and increases the expression of p-JNK, NF-κB, and cleaved caspase-3. However, inhibition of RAC1 ameliorated DN by downregulating p-JNK, NF-κB, and cleaved caspase-3. Also, RAC1 promoted the assembly of MLK3-MKK7-JNK, and NSC23766 blocked the interaction between RAC1 and MLK3-MKK7-JNK and inhibited the assembly of the MLK3-MKK7-JNK signaling module. Furthermore, RAC1 was combined with MLK3 directly, but the RAC1 Y40C mutant inhibited the interaction between RAC1 and MLK3. We demonstrated that RAC1 combining with MLK3 activates the MLK3-MKK7-JNK signaling module, accelerating DN occurrence and development, and RAC1 Y40 is an important site for binding of RAC1 to MLK3. This study illustrates the cellular and molecular mechanisms of how RAC1 accelerates DN and provides evidence of DN-targeted therapy.

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MAPK-induced Ser727 phosphorylation promotes SUMOylation of STAT1

Biochemical Journal ◽

10.1042/bj20070620 ◽

2007 ◽

Vol 409 (1) ◽

pp. 179-185 ◽

Cited By ~ 33

Author(s):

Sari Vanhatupa ◽

Daniela Ungureanu ◽

Maija Paakkunainen ◽

Olli Silvennoinen

Keyword(s):

Interferon Γ ◽

Dominant Negative ◽

Mitogen Activated Protein Kinase ◽

Extracellular Signal Regulated Kinase ◽

Extracellular Signal ◽

Microbial Infections ◽

Mitogen Activated Protein ◽

P38mapk Pathway ◽

Ifn Γ

STAT1 (signal transducer and activator of transcription 1) is a critical mediator of IFN-γ (interferon-γ)-induced gene responses, and its function is regulated through phosphorylation of Tyr701 and Ser727. MAPK (mitogen-activated protein kinase) pathways mediate phosphorylation of Ser727 in response to microbial infections, stress stimuli and growth factors. Recently, STAT1 was found to become modified by PIAS (protein inhibitor of activated STAT)-mediated SUMO-1 (small ubiquitin-related modifier-1) conjugation at Lys703, but the regulation of this modification is largely unknown. Here, we have investigated the role of MAPK-induced Ser727 phosphorylation in regulation of STAT1 SUMOylation. Activation of the p38MAPK pathway by upstream activating kinase, MKK6 (MAPK kinase-6) or osmotic stress enhanced the SUMOylation of STAT1, which was counteracted by the p38MAPK inhibitor SB202190 or by dominant-negative p38MAPK. Activation of the ERK1/2 (extracellular-signal-regulated kinase 1/2) pathway by Raf-1 also enhanced Ser727 phosphorylation and SUMOylation of STAT1, and this induction was counteracted by PD98059 inhibitor. Mutation of Ser727 to alanine abolished the p38MAPK-induced SUMOylation. Furthermore, S727D and S727E mutations, which mimic the phosphorylation of Ser727, enhanced the basal SUMOylation of STAT1 and interaction between PIAS1 and STAT1. Taken together, these results identify Ser727 phosphorylation as a regulator of STAT1 SUMOylation and highlight the central role of Ser727 in co-ordination of STAT1 functions in cellular responses.

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Differential activation of stress-activated protein kinase kinases SKK4/MKK7 and SKK1/MKK4 by the mixed-lineage kinase-2 and mitogen-activated protein kinase kinase (MKK) kinase-1

Biochemical Journal ◽

10.1042/bj3330011 ◽

1998 ◽

Vol 333 (1) ◽

pp. 11-15 ◽

Cited By ~ 45

Author(s):

Ana CUENDA ◽

Donna S. DOROW

Keyword(s):

Protein Kinase ◽

Interleukin 1 ◽

Mitogen Activated Protein Kinase ◽

Mapk Kinase ◽

Mixed Lineage Kinase ◽

Mitogen Activated Protein ◽

Necrosis Factor ◽

Pro Inflammatory Cytokines ◽

Protein Kinase Kinase

Overexpression of the protein kinases mixed-lineage kinase-2 (MLK2) or mitogen-activated protein kinase (MAPK) kinase kinase-1 (MEKK1) is known to trigger the activation of stress-activated protein kinase (SAPK1)/c-Jun N-terminal kinase (JNK). Here we demonstrate that MLK2 activates SAPK kinase-1 (SKK1)/MAPK kinase 4 (MKK4) and SKK4/MKK7, the two known direct activators of SAPK1/JNK (both in transfection studies and in vitro). In contrast, MEKK1 activates SKK1/MKK4 more efficiently than MLK2, but barely activates SKK4/MKK7. Since SKK4/MKK7 (but not SKK1/MKK4) is activated by interleukin-1 and tumour necrosis factor in several cells and tissues, we suggest that MEKK1 does not mediate the activation of SKK4/MKK7 and SAPK1/JNK induced by these pro-inflammatory cytokines. MLK2 and MEKK1 also activated SKK2/MKK3 and SKK3/MKK6, the direct upstream activators of SAPK2a/p38.

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Involvement of mixed lineage kinase 3 in cancer

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2012-0258 ◽

2013 ◽

Vol 91 (4) ◽

pp. 268-274 ◽

Cited By ~ 8

Author(s):

Deborah N. Chadee

Keyword(s):

Signaling Pathways ◽

Cellular Responses ◽

Mapk Signaling ◽

Mitogen Activated Protein Kinase ◽

Migration And Invasion ◽

Cancer Treatments ◽

Mixed Lineage Kinase ◽

Mitogen Activated Protein ◽

Mixed Lineage Kinase 3 ◽

Mapk Signaling Pathways

Mitogen-activated protein kinase (MAPK) signaling pathways are composed of a phosphorelay signaling module where an activated MAP kinase kinase kinase (MAP3K) phosphorylates and activates a MAPK kinase (MAP2K) that in turn phosphorylates and activates a MAPK. The biological outcome of MAPK signaling is the regulation of cellular responses such as proliferation, differentiation, migration, and apoptosis. The MAP3K mixed lineage kinase 3 (MLK3) phosphorylates MAP2Ks to activate multiple MAPK signaling pathways, and MLK3 also has functions in cell signaling that are independent of its kinase activity. The recent elucidation of essential functions for MLK3 in tumour cell proliferation, migration, and invasion has drawn attention to the MLKs as potential therapeutic targets for cancer treatments. The mounting evidence that suggests a role for MLK3 in tumourigenesis and establishment of the malignant phenotype is the focus of this review.

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Thyroid hormone induces activation of mitogen-activated protein kinase in cultured cells

AJP Cell Physiology ◽

10.1152/ajpcell.1999.276.5.c1014 ◽

1999 ◽

Vol 276 (5) ◽

pp. C1014-C1024 ◽

Cited By ~ 148

Author(s):

Hung-Yun Lin ◽

Faith B. Davis ◽

Jennifer K. Gordinier ◽

Leon J. Martino ◽

Paul J. Davis

Keyword(s):

Thyroid Hormone ◽

Protein Kinase ◽

Nuclear Translocation ◽

Cultured Cells ◽

Mapk Pathway ◽

Interferon Γ ◽

Mitogen Activated Protein Kinase ◽

Mitogen Activated Protein ◽

Ifn Γ ◽

G Protein Coupled

Thyroid hormone [l-thyroxine (T4)] rapidly induced phosphorylation and nuclear translocation (activation) of mitogen-activated protein kinase (MAPK) in HeLa and CV-1 cells in the absence of cytokine or growth factor. A pertussis toxin-sensitive and guanosine 5′- O-(3-thiotriphosphate)-sensitive cell surface mechanism responsive to T4and agarose-T4, suggesting a G protein-coupled receptor, was implicated. Cells depleted of MAPK or treated with MAPK pathway inhibitors showed reduced activation of MAPK and of the signal transducer and activator of transcription STAT1α by T4; they also showed reduced T4potentiation of the antiviral action of interferon-γ (IFN-γ). T4treatment caused tyrosine-phosphorylated MAPK-STAT1α nuclear complex formation and enhanced Ser-727 phosphorylation of STAT1α, in the presence or absence of IFN-γ. STAT1α-deficient cells transfected with STAT1α containing an alanine-for-serine substitution at residue 727 (STAT1αA727) showed minimal T4-stimulated STAT1α activation. IFN-γ induced the antiviral state in cells containing wild-type STAT1α (STAT1αwt) or STAT1αA727; T4potentiated IFN-γ action in STAT1αwtcells but not in STAT1αA727cells. T4-directed STAT1α Ser-727 phosphorylation is MAPK mediated and results in potentiated STAT1α activation and enhanced IFN-γ activity.

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Regulation of CX3CL1 Expression in Human First-Trimester Decidual Cells: Implications for Preeclampsia

Reproductive Sciences ◽

10.1177/1933719118815592 ◽

2019 ◽

Vol 26 (9) ◽

pp. 1256-1265 ◽

Cited By ~ 4

Author(s):

S. Joseph Huang ◽

Chie-Pein Chen ◽

Lynn Buchwalder ◽

Ya-Chun Yu ◽

Longzhu Piao ◽

...

Keyword(s):

Protein Kinase ◽

Nk Cells ◽

Nk Cell ◽

First Trimester ◽

Mitogen Activated Protein Kinase ◽

Decidual Cells ◽

Tnf Α ◽

Mitogen Activated Protein ◽

Ifn Γ ◽

Protein Kinase Kinase

C-X3-C motif ligand 1 (CX3CL1) mediates migration, survival, and adhesion of natural killer (NK) cells, monocytes, and T-cells to endothelial/epithelial cells. Aberrant numbers and/or activation of these decidual immune cells elicit preeclampsia development. Decidual macrophages and NK cells are critical for implantation, while macrophage-derived tumor necrosis factor-α (TNF-α), interleukin-1 β (IL-1β), and NK cell-derived interferon-γ (IFN-γ) are associated with preeclampsia development. Thus, serum and decidual levels of CX3CL1 from first-trimester pregnancy and preeclampsia-complicated term pregnancy were examined by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry, respectively. The effects of incubating primary human first-trimester decidual cells (FTDCs) with estradiol + medroxyprogesterone acetate + either IL-1β or TNF-α and/or IFN-γ on CX3CL1 expression were also assessed by quantitative reverse transcription-polymerase chain reaction and ELISA. The inhibition of each signaling pathway with each kinase and nuclear factor κB (NFκB) inhibitors was evaluated by ELISA. Chemotaxis of CD56brightCD16− NK cells by various concentrations of CX3CL1 was evaluated. C-X3-C motif ligand 1 is expressed by both cytotrophoblasts and decidual cells in first-trimester decidua. C-X3-C motif ligand 1 expression is increased in term decidua but unchanged in first-trimester and term serum of patients with preeclampsia. Interferon-gamma and either IL-1β or TNF-α synergistically upregulated CX3CL1 expression in FTDCs. Coincubation with IL-1β or TNF-α or IFN-γ, mitogen-activated protein kinase kinase 1 and 2 (MEK1/2), c-JUN N-terminal kinase (JNK), and NFκB inhibitors suppressed CX3CL1 production. C-X3-C motif ligand 1 elicited concentration-dependent enhancement of CD56brightCD16− NK cell migration. In conclusion, the current study suggests that decidual cell-secreted CX3CL1 is involved in the later development of preeclampsia, whereas circulating CX3CL1 levels do not predict preeclampsia. Mitogen-activated protein kinase kinase 1 and 2, JNK, and NFκB signaling mediate IL-1β-, TNF-α-, and IFN-γ-induced CX3CL1 production by FTDCs.

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