Ubiquitin-Specific Protease 2 Modulates the Lipopolysaccharide-Elicited Expression of Proinflammatory Cytokines in Macrophage-like HL-60 Cells

Abstract

We investigated the regulatory roles of USP2 in mRNA accumulation of proinflammatory cytokines in macrophage-like cells after stimulation with a toll-like receptor (TLR) 4 ligand, lipopolysaccharide (LPS). Human macrophage-like HL-60 cells, mouse macrophage-like J774.1 cells, and mouse peritoneal macrophages demonstrated negative feedback to USP2 mRNA levels after LPS stimulation, suggesting that USP2 plays a significant role in LPS-stimulated macrophages. USP2 knockdown (KD) by short hairpin RNA in HL-60 cells promoted the accumulation of transcripts for 25 of 104 cytokines after LPS stimulation. In contrast, limited induction of cytokines was observed in cells forcibly expressing the longer splice variant of USP2 (USP2A), or in peritoneal macrophages isolated from Usp2a transgenic mice. An ubiquitin isopeptidase-deficient USP2A mutant failed to suppress LPS-induced cytokine expression, suggesting that protein ubiquitination contributes to USP2-mediated cytokine repression. Although USP2 deficiency did not accelerate TNF receptor-associated factor (TRAF) 6-nuclear factor-κB (NF-κB) signaling, it increased the DNA binding ratio of the octamer binding transcription factor (Oct)-1 to Oct-2 in TNF, CXCL8, CCL4, and IL6 promoters. USP2 decreased nuclear Oct-2 protein levels in addition to decreasing the polyubiquitination of Oct-1. In summary, USP2 modulates proinflammatory cytokine induction, possibly through modification of Oct proteins, in macrophages following TLR4 activation.

The Challenge of the Sponge Suberites domuncula (Olivi, 1792) in the Presence of a Symbiotic Bacterium and a Pathogen Bacterium

“…This may suggest that TRAF-6 may be a relay protein between the S. domuncula TLR and further signaling pathways since both the TLR and TRAF-6 genes expression evolved in the same way in the presence of LPS. This is in agreement with some recent results found in the literature concerning mammals [43,44,45] as well as marine invertebrates [46,47,48,49]. Furthermore, concerning the pathogenic bacterium, it seems that TRAF-6 gene expression is mainly affected in response to one/several secreted molecules or vesicles.…”

Inhibition of ubiquitin‐specific protease 2 causes accumulation of reactive oxygen species, mitochondria dysfunction, and intracellular ATP decrement in C2C12 myoblasts

“…USP2, a member of the USP family, is widely expressed in organs, with relatively higher expression levels reported in the testis and skeletal muscle (Gousseva and Baker, 2003;Kitamura et al, 2013). It has diverse functions in a wide variety of cells, such as pro-and antiapoptotic effects in cancerous cells (Gewies and Grimm, 2003;Priolo et al, 2006), regulatory roles in cytokine production in macrophages (Zhang et al, 2014;Sun et al, 2016;Kitamura et al, 2017), and modulation of glucose and lipid metabolism (Molusky et al, 2012;Kitamura et al, 2013;Nelson et al, 2016;Saito et al, 2017). In a previous study, dominant negative forms of USP2 were found to interrupt the differentiation of L6 myoblasts into myofibers indicating the involvement of USP2 in myocyte differentiation (Park et al, 2002).…”

Potential of an Interorgan Network Mediated by Toxic Advanced Glycation End-Products in a Rat Model

“…Takahashi et al reported that lipid droplet formation in adipocytes promotes fat synthesis via activation of SREBP-1 and that promotes further lipid droplet formation [ 52 ]. Decreased expression of USP2 induced by HFCS administration is reported to contribute to inflammation in adipose tissue and increase low-density lipoprotein (LDL) cholesterol [ 53 , 54 ]. Knockdown of Usp2 expression in the human myeloid cell line HL-60 is reported to alter the expression of genes involved in the progression of chronic inflammation and type 2 diabetes in adipose tissues, including aP2 , PAI-1 , and MCP-1 [ 53 ].…”