Mechanism of TCONS_00147848 regulating apoptosis of nasal mucosa cells and alleviating allergic rhinitis through FOSL2-mediated JAK/STAT3 signaling pathway.

This study was conducted to explore the roles and related mechanisms of lncRNA-TCONS_00147848 (TCONS_00147848) in nasal mucosa cell apoptosis and allergic rhinitis (AR). AR mice were sensitized with ovalbumin (OVA), with the TCONS_00147848 interference lentiviral vector (TCONS_00147848 shRNA) and FOSL2 overexpressing lentiviral vectors (pCDH-FOSL2) constructed respectively. NC shRNA, TCONS_00147848 shRNA and TCONS_00147848 shRNA + pCDH-FOSL2 were transfected into AR mice and mice with TNF-α induced nasal mucosa cells. The allergic reaction symptoms were evaluated by scoring. And in this study, we used Hematoxylin-Eosin (HE) staining and Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) to detect the histological changes of nasal mucosa and apoptosis of nasal mucosa epithelial cells in mice, cell counting kit-8 (CCK-8) assay, Transwell and annexin V/PI to detect proliferation, migration and apoptosis of nasal mucosa cells of mice, respectively, enzyme-linked immunosorbent assay (ELISA) to detect the expression of inflammatory factors, qRT-PCR to detect TCONS_00147848 expression, Western blot assay to detect the expressions of FOSL2, JAK-2, STAT3, p-STAT3, BAX and BCL-2, RNA-binding protein immunoprecipitation (RIP) assay, RNA pull down assay and Co-immunoprecipitation (CoIP) assay to identify TCONS_00147848 targeting FOSL2. All these findings above reveal that knocking down TCONS_00147848 can reduce the allergic reaction symptom score of AR mice and the inflammatory reaction. The expression of IgE, IL-4, IL-5, IL-10, IL-9, IFN-γ and TNF-α in serum decreased. The expression of FOSL2, JAK-2, p-STAT3 and BAX in nasal mucosa and nasal mucosa cells of mice decreased as well, but BCL-2 expression increased. In addition, koncking down TCONS_00147848 can also inhibit the apoptosis of TNF-α induced nasal mucosa cells in mice and promote cell proliferation and migration. However, FOSL2 overexpression neutralized the effect of TCONS_00147848 shRNA. In nasal mucosa cells of mice, TCONS_00147848 can target FOSL2, interacting with STAT3. Inhibition of TCONS_00147848 can regulate JAK/STAT3 signaling pathway and reduce inflammatory response in AR mice.

Transcriptional regulation of the mouse CD11c promoter by AP-1 complex with JunD and Fra2 in dendritic cells.

CD11c, a member of the ß(2) integrin family of adhesion molecule, is expressed on the surface of myeloid lineages and activated lymphoid cells and forms a heterodimeric receptor with CD18. We analyzed the mouse CD11c promoter structure to elucidate the transcriptional regulation in dendritic cells (DCs). By reporter assay, the -84/-65 region was identified to be essential for activity of the mouse CD11c promoter in the mouse bone marrow-derived (BM) DCs and monocyte cell line RAW264.7. An electrophoretic mobility shift assay using a number of antibodies against transcription factors revealed that the target region was recognized by a complex including JunD and Fra2, which are transcription factors belonging to the AP-1 family. The direct interaction of JunD and Fra2 with the CD11c promoter was further confirmed by a chromatin immunoprecipitation assay using CD11c-positive cells purified from BMDCs. Finally, mouse JunD and/or Fra2 siRNA was introduced into BMDCs to evaluate the involvement of these factors against CD11c transcription and found that Fra2 siRNA reduced cell surface expression level of CD11c. These results indicate that AP-1 composed with JunD and Fra2 protein plays a primary role in enhancing the transcription level of the CD11c gene in DC.

Endothelin-1 regulates rat bone sialoprotein gene transcription.

Endothelin-1 (ET-1) was originally discovered as a vasoconstrictor protein excreted by vascular endothelial cells. Recently, tumor-produced ET-1 has been considered to stimulate osteoblasts to form new bone, and to be an important mediator of osteoblastic bone metastasis. ET-1 has high affinity for two different membrane receptors, ET(A)R and ET(B)R, which are expressed by many types of cells including osteoblasts. Bone sialoprotein (BSP) is a phosphorylated and sulfated glycoprotein associated with mineralized connective tissues. To investigate the effects of ET-1 on BSP transcription, we used rat osteoblast-like ROS17/2.8 cells. Levels of BSP and osteopontin mRNA were increased at 12 h after treatment with ET-1 (10 ng/ml), and ET-1 at the same concentration induced luciferase activity of a -116 to +60 BSP promoter construct at 6 h. Transcriptional activity of -84BSPLUC, which contains the cAMP response element (CRE), was increased by ET-1. Furthermore, at 6 h, ET-1 (10 ng/ml) increased the binding of nuclear protein to CRE, the FGF2 response element (FRE) and the homeodomain protein-binding site (HOX). Antibodies against CREB1, JunD and Fra2 disrupted the formation of CRE-protein complexes, while antibodies against Runx2 and Dlx5 reduced the formation of FRE- and HOX-protein complexes. These findings indicate that ET-1 increases BSP transcription via the CRE, FRE and HOX sites in the rat BSP gene promoter.

Aberrant expression of Fra-2 promotes CCR4 expression and cell proliferation in adult T-cell leukemia.

Adult T-cell leukemia (ATL) is a mature CD4+ T-cell malignancy etiologically associated with human T-cell leukemia virus type 1 (HTLV-1). Primary ATL cells frequently express CCR4 at high levels. Since HTLV-1 Tax does not induce CCR4 expression, transcription factor(s) constitutively active in ATL may be responsible for its strong expression. We identified an activator protein-1 (AP-1) site in the CCR4 promoter as the major positive regulatory element in ATL cells. Among the AP-1 family members, Fra-2, JunB and JunD are highly expressed in fresh primary ATL cells. Consistently, the Fra-2/JunB and Fra-2/JunD heterodimers strongly activated the CCR4 promoter in Jurkat cells. Furthermore, Fra-2 small interfering RNA (siRNA) or JunD siRNA, but not JunB siRNA, effectively reduced CCR4 expression and cell growth in ATL cells. Conversely, Fra-2 or JunD overexpression promoted cell growth in Jurkat cells. We identified 49 genes, including c-Myb, BCL-6 and MDM2, which were downregulated by Fra-2 siRNA in ATL cells. c-Myb, BCL-6 and MDM2 were also downregulated by JunD siRNA. As Fra-2, these proto-oncogenes were highly expressed in primary ATL cells but not in normal CD4+ T cells. Collectively, aberrantly expressed Fra-2 in association with JunD may play a major role in CCR4 expression and oncogenesis in ATL.

The role of inducible repressor proteins in the adrenergic induction of arylalkylamine-N-acetyltransferase and mitogen-activated protein kinase phosphatase-1 in rat pinealocytes.

In this study, we investigated the role of two inducible repressor proteins, inducible cAMP early repressor (ICER) and Fos-related antigen 2 (Fra-2) in the adrenergic induction of MAPK phosphatase-1 (MKP-1) as compared with their roles in the induction of arylalkylamine-N-acetyltransferase (AA-NAT) in rat pinealocytes. Treatment of pinealocytes with norepinephrine (NE) caused an increase in the mRNA and protein levels of MKP-1 and AA-NAT, as well as in the AA-NAT activity and melatonin production. NE stimulation also caused a simultaneous increase in the mRNA and protein levels of ICER and Fra-2. Transient knockdown of icer using adenovirus expressing small interfering RNA (siRNA) abolished the NE induction of icer expression but had little effect on the NE induction of mkp-1 or aa-nat expression. In contrast, pretreatment with adenovirus overexpressing icer was effective in reducing the NE induction of mkp-1 and aa-nat. The inhibitory effect of overexpressing icer was reversed by cotreatment with siRNA against icer. siRNA against fra-2 also abolished the NE-stimulated expression of fra-2 but had little effect on the NE induction of mkp-1 and aa-nat expression. Proteasomal inhibition, which reduced the NE-stimulated induction of aa-nat, caused a reduction of ICER and Fra-2. Together, these results indicate that whereas overexpression of ICER can suppress the NE induction of aa-nat and mkp-1, the amount of the repressors, ICER and Fra-2, present during NE induction appears insufficient to exert a significant effect in controlling the expression of these genes.