Dual-Specificity Phosphatase 12 Targets p38 MAP Kinase to Regulate Macrophage Response to Intracellular Bacterial Infection

Abstract

The mitogen-activated protein kinase (MAPK) cascades are activated in innate immune cells such as macrophages upon the detection of microbial infection, critically regulating the expression of proinflammatory cytokines and chemokines such as TNF-α, IL-6, and MCP-1. As a result, activation of MAPKs is tightly regulated to ensure appropriate and adequate immune responses. Dual-specificity phosphatases (DUSPs) are a family of proteins which specifically dephosphorylates threonine and tyrosine residues essential for MAPK activation to negatively regulate their activation. DUSP12 is a member of atypical DUSPs that lack MAPK-binding domain. Its substrate and function in immune cells are unknown. In this study, we demonstrated that DUSP12 is able to interact with all the three groups of MAPKs, including extracellular signal-regulated protein kinase, JNK, and p38. To investigate the function of DUSP12 in macrophages in response to TLR activation and microbial infection, we established RAW264.7 cell lines stably overexpressing DUSP12 and found that overexpression of DUSP12 inhibited proinflammatory cytokine and chemokine production in response to TLR4 activation, heat-inactivated Mycobacterium tuberculosis stimulation as well as infections by intracellular bacteria including Listeria moncytogenesis and Mycobacterium bovis BCG by specifically inhibiting p38 and JNK. In addition, a scaffold protein known as signal transducing adaptor protein 2 (STAP2), was found to mediate the interaction between DUSP12 and p38. Thus, DUSP12 is a bona fide MAPK phosphatase, playing an important role in MAPK-regulated responses to bacterial infection. Our study provides a model where atypical DUSPs regulate MAPKs via scaffold, thereby regulating immune responses to microbial infection.

Dual Specificity Phosphatase 12 Regulates Hepatic Lipid Metabolism Through Inhibition of the Lipogenesis and Apoptosis Signal–Regulating Kinase 1 Pathways

“…Subsequently, we investigated the mechanisms by which DUSP12 inhibits the progression of NAFLD/NASH. Considering that DUSP12 could regulate microbial infection and cardiac hypertrophy through modulating MAPK signaling, MAPK pathways are well known to regulate metabolic dysfunction and hepatic steatosis during the pathogenesis of NAFLD . Thus, we examined whether DUSP12 could regulate MAPK signaling in hepatic steatosis.…”

“…Additionally, ectopic expression of DUSP12 using a retroviral expression system induced the suppression of adipogenic differentiation and lipid accumulation . More recently, studies showed that DUSP12 could protect against microbial infection by inhibiting MAPK‐mediated expression of proinflammatory mediators such as tumor necrosis factor alpha (TNF‐α), interleukin (IL)‐1β, and monocyte chemoattractant protein 1 . Providing further support, DUSP12 deficiency apparently aggravated pressure overload–induced cardiac hypertrophy and fibrosis by inhibiting activation of JUN N‐terminal kinase (JNK) .…”

Phosphorylation Dynamics of JNK Signaling: Effects of Dual-Specificity Phosphatases (DUSPs) on the JNK Pathway

“…DUSP7, DUSP12, DUSP13B, and DUSP18 have also been analyzed as dephosphorylating and inactivating regulators of JNK [73,83,95,114]. When DUSP12 was overexpressed in RAW264.7 cells that were stimulated with LPS, the level of p-JNK was significantly reduced over time compared with control cells [114].…”

Investigation of the Genome-Wide Genetic and Epigenetic Networks for Drug Discovery Based on Systems Biology Approaches in Colorectal Cancer

“…In the left-pathway in the early-stage CRC cells, the ligand PTK6 binds to the receptor STAP2 phosphorylated in the hypoxic microenvironment (Semenza, 2016). While STAP2 is modified by phosphorylation, the signal is transmitted to cascade proteins TUBB1, armadillo repeat containing 8 (ARMC8), and MAP4K1 (Fujita et al, 2014;Cho et al, 2017). At this point, with signal coupling from SIM1, the pathway activates the MAPK signaling pathway which is related to the control of immune response.…”

“…Based on the investigation of the core genetic and epigenetic network, we identified some pathogenic biomarkers for the design of multiple drugs against CRC. In early-stage disease, PTK6 (hypoxic environment) binds with STAP2 to activate essential protein MAP4K1 and consequently the MAPK pathway (Fujita et al, 2014;Cho et al, 2017). WIF1 (Signal transduction) binds with WNT4 to activate the WNT signaling pathway (Seth and Ruiz I Altaba, 2016;Tang et al, 2018).…”