JAK1 palmitoylation by ZDHHC3/7 is Essential for Neuropoietic Cytokine Signaling and DRG Neuron Survival

AbstractJanus Kinase-1 (JAK1) plays key roles in pro-survival signaling during neurodevelopment and in responses to neuronal injury. JAK1 was identified as a potential palmitoyl-protein in high-throughput studies, but the importance of palmitoylation for JAK1’s roles in neurons has not been addressed. Here, we report that JAK1 is endogenously palmitoylated in cultured Dorsal Root Ganglion (DRG) neurons and, using an shRNA knockdown/rescue approach, reveal that JAK1 palmitoylation is important for neuropoietic cytokine-dependent signaling and neuronal survival. We further identify the related palmitoyl acyltransferases (PATs) ZDHHC3 and ZDHHC7 as dominant regulators of JAK1 palmitoylation in transfected non-neuronal cells and endogenously in neurons. At the molecular level, palmitoylation is critical for JAK1’s kinase activity in transfected cells and even in vitro, likely because palmitoylation facilitates transphosphorylation of key sites in the JAK1 activation loop. These findings provide new insights into palmitoylation-dependent control of neuronal development and survival.

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Exendin-4 Promotes Schwann Cell Survival/Migration and Myelination In Vitro

International Journal of Molecular Sciences ◽

10.3390/ijms22062971 ◽

2021 ◽

Vol 22 (6) ◽

pp. 2971

Author(s):

Shizuka Takaku ◽

Masami Tsukamoto ◽

Naoko Niimi ◽

Hideji Yako ◽

Kazunori Sango

Keyword(s):

Phosphatidyl Inositol ◽

Specific Protein ◽

Myelin Protein ◽

Drg Neurons ◽

Antibody Treatment ◽

Pi3k Inhibitor Ly294002 ◽

Adult Rat ◽

Drg Neuron ◽

Peripheral Nerve Lesions

Besides its insulinotropic actions on pancreatic β cells, neuroprotective activities of glucagon-like peptide-1 (GLP-1) have attracted attention. The efficacy of a GLP-1 receptor (GLP-1R) agonist exendin-4 (Ex-4) for functional repair after sciatic nerve injury and amelioration of diabetic peripheral neuropathy (DPN) has been reported; however, the underlying mechanisms remain unclear. In this study, the bioactivities of Ex-4 on immortalized adult rat Schwann cells IFRS1 and adult rat dorsal root ganglion (DRG) neuron–IFRS1 co-culture system were investigated. Localization of GLP-1R in both DRG neurons and IFRS1 cells were confirmed using knockout-validated monoclonal Mab7F38 antibody. Treatment with 100 nM Ex-4 significantly enhanced survival/proliferation and migration of IFRS1 cells, as well as stimulated the movement of IFRS1 cells toward neurites emerging from DRG neuron cell bodies in the co-culture with the upregulation of myelin protein 22 and myelin protein zero. Because Ex-4 induced phosphorylation of serine/threonine-specific protein kinase AKT in these cells and its effects on DRG neurons and IFRS1 cells were attenuated by phosphatidyl inositol-3′-phosphate-kinase (PI3K) inhibitor LY294002, Ex-4 might act on both cells to activate PI3K/AKT signaling pathway, thereby promoting myelination in the co-culture. These findings imply the potential efficacy of Ex-4 toward DPN and other peripheral nerve lesions.

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Tofacitinib Suppresses Several JAK-STAT Pathways in Rheumatoid Arthritis In Vivo and Baseline Signaling Profile Associates With Treatment Response

Frontiers in Immunology ◽

10.3389/fimmu.2021.738481 ◽

2021 ◽

Vol 12 ◽

Author(s):

Maaria Palmroth ◽

Krista Kuuliala ◽

Ritva Peltomaa ◽

Anniina Virtanen ◽

Antti Kuuliala ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

T Cells ◽

Treatment Response ◽

Peripheral Blood ◽

Janus Kinase ◽

Cytokine Signaling ◽

Stat3 Phosphorylation ◽

Stat Pathway

ObjectiveCurrent knowledge on the actions of tofacitinib on cytokine signaling pathways in rheumatoid arthritis (RA) is based on in vitro studies. Our study is the first to examine the effects of tofacitinib treatment on Janus kinase (JAK) - signal transducer and activator of transcription (STAT) pathways in vivo in patients with RA.MethodsSixteen patients with active RA, despite treatment with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), received tofacitinib 5 mg twice daily for three months. Levels of constitutive and cytokine-induced phosphorylated STATs in peripheral blood monocytes, T cells and B cells were measured by flow cytometry at baseline and three-month visits. mRNA expression of JAKs, STATs and suppressors of cytokine signaling (SOCS) were measured from peripheral blood mononuclear cells (PBMCs) by quantitative PCR. Association of baseline signaling profile with treatment response was also investigated.ResultsTofacitinib, in csDMARDs background, decreased median disease activity score (DAS28) from 4.4 to 2.6 (p < 0.001). Tofacitinib treatment significantly decreased cytokine-induced phosphorylation of all JAK-STAT pathways studied. However, the magnitude of the inhibitory effect depended on the cytokine and cell type studied, varying from 10% to 73% inhibition following 3-month treatment with tofacitinib. In general, strongest inhibition by tofacitinib was observed with STAT phosphorylations induced by cytokines signaling through the common-γ-chain cytokine receptor in T cells, while lowest inhibition was demonstrated for IL-10 -induced STAT3 phosphorylation in monocytes. Constitutive STAT1, STAT3, STAT4 and STAT5 phosphorylation in monocytes and/or T cells was also downregulated by tofacitinib. Tofacitinib treatment downregulated the expression of several JAK-STAT pathway components in PBMCs, SOCSs showing the strongest downregulation. Baseline STAT phosphorylation levels in T cells and monocytes and SOCS3 expression in PBMCs correlated with treatment response.ConclusionsTofacitinib suppresses multiple JAK-STAT pathways in cytokine and cell population specific manner in RA patients in vivo. Besides directly inhibiting JAK activation, tofacitinib downregulates the expression of JAK-STAT pathway components. This may modulate the effects of tofacitinib on JAK-STAT pathway activation in vivo and explain some of the differential findings between the current study and previous in vitro studies. Finally, baseline immunological markers associate with the treatment response to tofacitinib.

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SOCS1/SOCS3 Immune Axis Modulates Synthetic Perturbations in IL6 Biological Circuit for Dynamical Cellular Response

10.1101/2020.08.31.276634 ◽

2020 ◽

Author(s):

Bhavnita Soni ◽

Shailza Singh

Keyword(s):

Signaling Pathway ◽

Cellular Response ◽

Inflammatory Cytokine ◽

Cytokine Expression ◽

Janus Kinase ◽

Cytokine Signaling ◽

Macrophage Phenotype ◽

Regulatory Circuit ◽

Stat Pathway

AbstractMacrophage phenotype plays a crucial role in the pathogenesis of Leishmanial infection. Pro-inflammatory cytokines are the key regulators that eliminate the infection induced by Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. Suppressor of cytokine signaling (SOCS) is a well-known negative feedback regulator of JAK/STAT pathway. However, change in expression levels of SOCS in correlation with the establishment of infection is not well understood. Mathematical modeling of IL6 signaling pathway have helped identified the role of SOCS1 in establishment of infection. Furthermore, the ratio of SOCS1 and SOCS3 has been quantified both in silico as well as in vitro, indicating an immune axis which governs the macrophage phenotype during L. major infection. The ability of SOCS1 protein to inhibit the JAK/STAT1 signaling pathway and thereby decreasing pro-inflammatory cytokine expression makes it a strong candidate for therapeutic intervention. Using synthetic biology approaches, peptide based immuno-regulatory circuit have been designed to target the activity of SOCS1 which can restore pro-inflammatory cytokine expression during infection.

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Interleukin-6 and interleukin-11: same same but different

Biological Chemistry ◽

10.1515/hsz-2013-0166 ◽

2013 ◽

Vol 394 (9) ◽

pp. 1145-1161 ◽

Cited By ~ 73

Author(s):

Christoph Garbers ◽

Jürgen Scheller

Keyword(s):

Neuronal Development ◽

Inflammatory Diseases ◽

Janus Kinase ◽

Mitogen Activated Protein Kinase ◽

Cytokine Signaling ◽

Downstream Signaling ◽

Mitogen Activated Protein ◽

Β Receptor ◽

Redundant Functions

Abstract The pleiotropic physiological functions of interleukin (IL-)6 type cytokines range from embryonic development and tissue homoeostasis to neuronal development and T cell differentiation. In contrast, imbalance of the well-controlled cytokine signaling network leads to chronic inflammatory diseases and cancer. IL-6 and IL-11 both signal through a homodimer of the ubiquitously expressed β-receptor glycoprotein 130 (gp130). Specificity is gained through an individual IL-6/IL-11 α-receptor, which does not directly participate in signal transduction, although the initial cytokine binding event to the α-receptor leads to the final complex formation with the β-receptors. Both cytokines activate the same downstream signaling pathways, which are predominantly the mitogen-activated protein kinase (MAPK)-cascade and the Janus kinase/signal transducer and activator of transcription (Jak/STAT) pathway. However, recent studies have highlighted divergent roles of the two related cytokines. Here, we will discuss how the biochemical similarities are translated into unique and non-redundant functions of IL-6 and IL-11 in vivo and illustrate strategies for cytokine-specific therapeutic intervention.

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Quercetin Preservesβ-Cell Mass and Function in Fructose-Induced Hyperinsulinemia through Modulating Pancreatic Akt/FoxO1 Activation

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2013/303902 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 10

Author(s):

Jian-Mei Li ◽

Wei Wang ◽

Chen-Yu Fan ◽

Ming-Xing Wang ◽

Xian Zhang ◽

...

Keyword(s):

Serum Insulin ◽

Cell Mass ◽

Janus Kinase ◽

Cytokine Signaling ◽

Akt Phosphorylation ◽

High Fructose ◽

Stat3 Phosphorylation ◽

And Function

Fructose-induced hyperinsulinemia is associated with insulin compensative secretion and predicts the onset of type 2 diabetes. In this study, we investigated the preservation of dietary flavonoid quercetin on pancreaticβ-cell mass and function in fructose-treated rats and INS-1β-cells. Quercetin was confirmed to reduce serum insulin and leptin levels and blockade islet hyperplasia in fructose-fed rats. It also prevented fructose-inducedβ-cell proliferation and insulin hypersecretion in INS-1β-cells. High fructose increased forkhead box protein O1 (FoxO1) expressionsin vivoandin vitro, which were reversed by quercetin. Quercetin downregulated Akt and FoxO1 phosphorylation in fructose-fed rat islets and increased the nuclear FoxO1 levels in fructose-treated INS-1β-cells. The elevated Akt phosphorylation in fructose-treated INS-1β-cells was also restored by quercetin. Additionally, quercetin suppressed the expression of pancreatic and duodenal homeobox 1 (Pdx1) and insulin gene (Ins1 and Ins2)in vivoandin vitro. In fructose-treated INS-1β-cells, quercetin elevated the reduced janus kinase 2/signal transducers and activators of transcription 3 (Jak2/Stat3) phosphorylation and suppressed the increased suppressor of cytokine signaling 3 (Socs3) expression. These results demonstrate that quercetin protectsβ-cell mass and function under high-fructose induction through improving leptin signaling and preserving pancreatic Akt/FoxO1 activation.

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JAK2 Tyrosine Kinase Phosphorylates and Is Negatively Regulated by Centrosomal Protein Ninein

Molecular and Cellular Biology ◽

10.1128/mcb.01138-14 ◽

2014 ◽

Vol 35 (1) ◽

pp. 111-131 ◽

Cited By ~ 8

Author(s):

Jennifer Jay ◽

Alan Hammer ◽

Andrea Nestor-Kalinoski ◽

Maria Diakonova

Keyword(s):

Tyrosine Kinase ◽

Kinase Activity ◽

Cytokine Signaling ◽

Centrosomal Protein ◽

C Terminus ◽

Dependent Inhibition ◽

Important Regulator ◽

Terminal Amino ◽

Tyrosyl Phosphorylation

JAK2 is a cytoplasmic tyrosine kinase critical for cytokine signaling. In this study, we have identified a novel centrosome-associated complex containing ninein and JAK2. We have found that active JAK2 localizes around the mother centrioles, where it partly colocalizes with ninein, a protein involved in microtubule (MT) nucleation and anchoring. We demonstrated that JAK2 is an important regulator of centrosome function. Depletion of JAK2 or use of JAK2-null cells causes defects in MT anchoring and increased numbers of cells with mitotic defects; however, MT nucleation is unaffected. We showed that JAK2 directly phosphorylates the N terminus of ninein while the C terminus of ninein inhibits JAK2 kinase activityin vitro. Overexpressed wild-type (WT) or C-terminal (amino acids 1179 to 1931) ninein inhibits JAK2. This ninein-dependent inhibition of JAK2 significantly decreases prolactin- and interferon gamma (IFN-γ)-induced tyrosyl phosphorylation of STAT1 and STAT5. Downregulation of ninein enhances JAK2 activation. These results indicate that JAK2 is a novel member of centrosome-associated complex and that this localization regulates both centrosomal function and JAK2 kinase activity, thus controlling cytokine-activated molecular pathways.

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Synthetic Perturbations in IL6 Biological Circuit Induces Dynamical Cellular Response

Molecules ◽

10.3390/molecules27010124 ◽

2021 ◽

Vol 27 (1) ◽

pp. 124

Author(s):

Bhavnita Soni ◽

Shailza Singh

Keyword(s):

Synthetic Biology ◽

Cellular Response ◽

Leishmania Major ◽

Early Stage ◽

Macrophage Polarization ◽

Janus Kinase ◽

Cytokine Signaling ◽

Macrophage Phenotype ◽

Stat Pathway

Macrophage phenotype plays a crucial role in the pathogenesis of Leishmanial infection. Pro-inflammatory cytokines signals through the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway that functions in parasite killing. Suppression of cytokine signaling (SOCS) is a well-known negative feedback regulator of the JAK/STAT pathway. However, change in the expression levels of SOCSs in correlation with the establishment of infection is not well understood. IL6 is a pleotropic cytokine that induces SOCS1 and SOCS3 expression through JAK-STAT signaling. Mathematical modeling of the TLR2 and IL6 signaling pathway has established the immune axis of SOCS1 and SOCS3 functioning in macrophage polarization during the early stage of Leishmania major infection. The ratio has been quantified both in silico and in vitro as 3:2 which is required to establish infection during the early stage. Furthermore, phosphorylated STAT1 and STAT3 have been established as an immunological cross talk between TLR2 and IL6 signaling pathways. Using synthetic biology approaches, peptide based immuno-regulatory circuits have been designed to target the activity of SOCS1 which can restore pro-inflammatory cytokine expression during infection. In a nutshell, we explored the potential of synthetic biology to address and rewire the immune response from Th2 to Th1 type during the early stage of leishmanial infection governed by SOCS1/SOCS3 immune axis.

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Antioxidant Effects of PS5, a Peptidomimetic of Suppressor of Cytokine Signaling 1, in Experimental Atherosclerosis

Antioxidants ◽

10.3390/antiox9080754 ◽

2020 ◽

Vol 9 (8) ◽

pp. 754

Author(s):

Sara La Manna ◽

Laura Lopez-Sanz ◽

Susana Bernal ◽

Luna Jimenez-Castilla ◽

Ignacio Prieto ◽

...

Keyword(s):

Gene Expression ◽

Experimental Atherosclerosis ◽

Janus Kinase ◽

Cytokine Signaling ◽

Antioxidant Genes ◽

Antioxidant Agents ◽

Atheroma Plaque ◽

Socs Proteins

The chronic activation of the Janus kinase/signal transducer and activator of the transcription (JAK/STAT) pathway is linked to oxidative stress, inflammation and cell proliferation. Suppressors of cytokine signaling (SOCS) proteins negatively regulate the JAK/STAT, and SOCS1 possesses a small kinase inhibitory region (KIR) involved in the inhibition of JAK kinases. Several studies showed that KIR-SOCS1 mimetics can be considered valuable therapeutics in several disorders (e.g., diabetes, neurological disorders and atherosclerosis). Herein, we investigated the antioxidant and atheroprotective effects of PS5, a peptidomimetic of KIR-SOCS1, both in vitro (vascular smooth muscle cells and macrophages) and in vivo (atherosclerosis mouse model) by analyzing gene expression, intracellular O2•− production and atheroma plaque progression and composition. PS5 was revealed to be able to attenuate NADPH oxidase (NOX1 and NOX4) and pro-inflammatory gene expression, to upregulate antioxidant genes and to reduce atheroma plaque size, lipid content and monocyte/macrophage accumulation. These findings confirm that KIR-SOCS1-based drugs could be excellent antioxidant agents to contrast atherosclerosis.

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