Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.25.1 (proteasome)
 28,817 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Allergic asthma and allergic dermatitis are chronic inflammatory diseases and are characterized by an accumulation of eosinophils at sites of inflammation. Eotaxin-1/CCL11 and eotaxin-3/CCL26 are members of the CC chemokine family, which are known to be potent chemoattractants for eosinophils. We observed that a human lung fibroblast, HFL-1 produces eotaxin-1 and -3 in response to TNF-alpha plus IL-4 stimulation, accompanied with NF-kappaB and STAT6 activation. We explored which signaling pathways are operative in the production of eotaxin-1 and -3 using several inhibitors. Eotaxin-1/CCL11 production was inhibited by a p38 mitogen-activated protein kinase (MAPK) inhibitor, SB203580, but not by the MEK (MAPK/ERK kinase) inhibitors, PD98059 and U0126. In contrast, eotaxin-3/CCL26 production was inhibited similarly by PD98059 as well as U0126 and SB203580. In addition, two proteasome inhibitors, N-acetyl-leucyl-leucyl-norleucinal (ALLN) and bortezomib with significant inhibitory activity on NF-kappaB activation, inhibited eotaxin-1/CCL11 production with IC50 8 microM for ALLN and IC50 16 nM for bortezomib. In contrast, eotaxin-3/CCL26 production was not inhibited significantly up to 10 microM of ALLN (IC50 16 microM) and up to 10 nM of bortezomib (IC50 11 nM), giving inhibition of eotaxin-3/CCL26 less sensitive than eotaxin-1/CCL11 production by the proteasome inhibitors. Synergistic inhibition was observed among lower doses of SB203580 and proteasome inhibitors, particularly in the eotaxin-1/CCL11 production. No such prominent synergism was found on the eotaxin-3/CCL26 production. The suppression of eotaxin family production by these inhibitors may be efficacious against allergic diseases.
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PMID:Differential regulation of eotaxin-1/CCL11 and eotaxin-3/CCL26 production by the TNF-alpha and IL-4 stimulated human lung fibroblast. 1675 1

Allergic asthma is a chronic lung disease initiated and driven by Th2 cytokines IL-4/-13. In macrophages, IL-4/-13 bind IL-4 receptors, which signal through insulin receptor substrate (IRS)-2, inducing M2 macrophage differentiation. M2 macrophages correlate with disease severity and poor lung function, although the mechanisms that regulate M2 polarization are not understood. Following IL-4 exposure, suppressor of cytokine signaling (SOCS)1 is highly induced in human monocytes. We found that siRNA knockdown of SOCS1 prolonged IRS-2 tyrosine phosphorylation and enhanced M2 differentiation, although siRNA knockdown of SOCS3 did not affect either. By co-immunoprecipitation, we found that SOCS1 complexes with IRS-2 at baseline, and this association increased after IL-4 stimulation. Because SOCS1 is an E3 ubiquitin ligase, we examined the effect of proteasome inhibitors on IL-4-induced IRS-2 phosphorylation. Proteasomal inhibition prolonged IRS-2 tyrosine phosphorylation, increased ubiquitination of IRS-2, and enhanced M2 gene expression. siRNA knockdown of SOCS1 inhibited ubiquitin accumulation on IRS-2, although siRNA knockdown of SOCS3 had no effect on ubiquitination of IRS-2. Monocytes from healthy and allergic individuals revealed that SOCS1 is induced by IL-4 in healthy monocytes but not allergic cells, whereas SOCS3 is highly induced in allergic monocytes. Healthy monocytes displayed greater ubiquitination of IRS-2 and lower M2 polarization than allergic monocytes in response to IL-4 stimulation. Here, we identify SOCS1 as a key negative regulator of IL-4-induced IRS-2 signaling and M2 differentiation. Our findings provide novel insight into how dysregulated expression of SOCS increases IL-4 responses in allergic monocytes, and this may represent a new therapeutic avenue for managing allergic disease.
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PMID:Suppressor of Cytokine Signaling (SOCS)1 Regulates Interleukin-4 (IL-4)-activated Insulin Receptor Substrate (IRS)-2 Tyrosine Phosphorylation in Monocytes and Macrophages via the Proteasome. 2750 12

Allergic asthma that is caused by inhalation of house dust mites (HDMs) is mainly mediated by Th2 cells. Recently, the roles of Sox (SRY-related high-mobility-group (HMG)-box) family members in various immune responses have been investigated. However, the roles of Sox12, a member of the SoxC group, in Th2 cell differentiation and allergic airway inflammation, remain unknown. We showed that Sox12 mRNA was significantly increased during Th2 cell differentiation. In vivo, HDM-induced eosinophil infiltration into the lung and Th2 cell differentiation were exacerbated in Sox12-/- mice compared with those in control Sox12+/- mice. In vitro, Sox12-/- CD4+ T cells that were cultured under Th2 conditions had increased production of Th2 cytokines and GATA3 protein compared with those of control Sox12+/- CD4+ T cells. Importantly, forced expression of Sox12 decreased the protein levels of GATA3 in CD4+ T cells under Th2 conditions without affecting mRNA expression. Furthermore, Sox12 induced degradation of GATA3 through the proteasome pathway in CD4+ T cells. Consistently, Sox12 enhanced ubiquitination of GATA3, which was mediated by the E3 ligase Fbw7. Finally, we found that Fbw7 knockdown partly abrogated Sox12-mediated GATA3 suppression in CD4+ T cells. Taken together, these results suggest that Sox12 suppresses Th2 cell differentiation by accelerating Fbw7-mediated GATA3 degradation, and attenuates HDM-induced allergic inflammation.
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PMID:Sox12 enhances Fbw7-mediated ubiquitination and degradation of GATA3 in Th2 cells. 3215 52