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JMJD8 is a positive regulator of TNF-induced NF- κ B signaling

View Article: PubMed Central - PubMed

ABSTRACT

TNF-induced signaling mediates pleiotropic biological consequences including inflammation, immunity, cell proliferation and apoptosis. Misregulation of TNF signaling has been attributed as a major cause of chronic inflammatory diseases and cancer. Jumonji domain-containing protein 8 (JMJD8) belongs to the JmjC family. However, only part of the family members has been described as hydroxylase enzymes that function as histone demethylases. Here, we report that JMJD8 positively regulates TNF-induced NF-κB signaling. Silencing the expression of JMJD8 using RNA interference (RNAi) greatly suppresses TNF-induced expression of several NF-κB-dependent genes. Furthermore, knockdown of JMJD8 expression reduces RIP ubiquitination, IKK kinase activity, delays IκBα degradation and subsequently blocks nuclear translocation of p65. In addition, JMJD8 deficiency enhances TNF-induced apoptosis. Taken together, these findings indicate that JMJD8 functions as a positive regulator of TNF-induced NF-κB signaling.

No MeSH data available.


JMJD8 deficiency promotes TNF-induced apoptosis.(a) Control and JMJD8 knockdown HEK293T cells were treated with either 10 ng/ml of TNFα alone or together with 5 μg/ml of Cyclohexamide (CHX) for 12 hours. Total cell lysates were prepared and immunoblotted with the indicated antibodies (n = 3). Full-length blots are presented in Supplementary Fig. S11.
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f5: JMJD8 deficiency promotes TNF-induced apoptosis.(a) Control and JMJD8 knockdown HEK293T cells were treated with either 10 ng/ml of TNFα alone or together with 5 μg/ml of Cyclohexamide (CHX) for 12 hours. Total cell lysates were prepared and immunoblotted with the indicated antibodies (n = 3). Full-length blots are presented in Supplementary Fig. S11.

Mentions: TNFα is a pleiotropic cytokine which can lead to two distinct cell fates which are the pro-survival path, mainly through the activation of pro-survival genes by NF-κB, or pro-apoptotic path through the signaling cascade of caspases activation4. We hypothesized that the defects in pro-survival path will favor the cells towards pro-apoptotic pathway. To investigate this speculation, we treated control and JMJD8 knockdown HEK293T cells with and without TNFα and examined apoptosis by immunoblotting total cell lysates with specific antibodies against caspase 3, cleaved-caspase 3, caspase 8 and PARP. TNF-only treatment induced a moderate level of apoptosis in control cells. Apoptosis was further enhanced in the presence of both TNF and cyclohexamide (CHX) as evidenced by the presence of cleaved PARP, reduced level of pro-caspase 3 and 8, and increased level of cleaved-caspase 3 and intermediate cleaved-caspase 8 (Fig. 5). In the absence of JMJD8, TNF-only treatment induced high level of apoptosis that was comparable to the control cells treated with both TNF and CHX. Collectively, these results indicate that JMJD8 is required for the pro-survival pathway of TNF-induced NF-κB signaling.


JMJD8 is a positive regulator of TNF-induced NF- κ B signaling
JMJD8 deficiency promotes TNF-induced apoptosis.(a) Control and JMJD8 knockdown HEK293T cells were treated with either 10 ng/ml of TNFα alone or together with 5 μg/ml of Cyclohexamide (CHX) for 12 hours. Total cell lysates were prepared and immunoblotted with the indicated antibodies (n = 3). Full-length blots are presented in Supplementary Fig. S11.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC5037431&req=5

f5: JMJD8 deficiency promotes TNF-induced apoptosis.(a) Control and JMJD8 knockdown HEK293T cells were treated with either 10 ng/ml of TNFα alone or together with 5 μg/ml of Cyclohexamide (CHX) for 12 hours. Total cell lysates were prepared and immunoblotted with the indicated antibodies (n = 3). Full-length blots are presented in Supplementary Fig. S11.
Mentions: TNFα is a pleiotropic cytokine which can lead to two distinct cell fates which are the pro-survival path, mainly through the activation of pro-survival genes by NF-κB, or pro-apoptotic path through the signaling cascade of caspases activation4. We hypothesized that the defects in pro-survival path will favor the cells towards pro-apoptotic pathway. To investigate this speculation, we treated control and JMJD8 knockdown HEK293T cells with and without TNFα and examined apoptosis by immunoblotting total cell lysates with specific antibodies against caspase 3, cleaved-caspase 3, caspase 8 and PARP. TNF-only treatment induced a moderate level of apoptosis in control cells. Apoptosis was further enhanced in the presence of both TNF and cyclohexamide (CHX) as evidenced by the presence of cleaved PARP, reduced level of pro-caspase 3 and 8, and increased level of cleaved-caspase 3 and intermediate cleaved-caspase 8 (Fig. 5). In the absence of JMJD8, TNF-only treatment induced high level of apoptosis that was comparable to the control cells treated with both TNF and CHX. Collectively, these results indicate that JMJD8 is required for the pro-survival pathway of TNF-induced NF-κB signaling.

View Article: PubMed Central - PubMed

ABSTRACT

TNF-induced signaling mediates pleiotropic biological consequences including inflammation, immunity, cell proliferation and apoptosis. Misregulation of TNF signaling has been attributed as a major cause of chronic inflammatory diseases and cancer. Jumonji domain-containing protein 8 (JMJD8) belongs to the JmjC family. However, only part of the family members has been described as hydroxylase enzymes that function as histone demethylases. Here, we report that JMJD8 positively regulates TNF-induced NF-κB signaling. Silencing the expression of JMJD8 using RNA interference (RNAi) greatly suppresses TNF-induced expression of several NF-κB-dependent genes. Furthermore, knockdown of JMJD8 expression reduces RIP ubiquitination, IKK kinase activity, delays IκBα degradation and subsequently blocks nuclear translocation of p65. In addition, JMJD8 deficiency enhances TNF-induced apoptosis. Taken together, these findings indicate that JMJD8 functions as a positive regulator of TNF-induced NF-κB signaling.

No MeSH data available.