Two interleukin-2 receptor-dependent signaling pathways have thus far been identified: the c-fos/c-jun induction pathway mediated by src family protein-tyrosine kinases and the c-myc induction pathway. Here, we provide evidence for the existence of a third, rapamycin-sensitive pathway, which results in the induction of another proto-oncogene, bcl-2. In the hematopoietic cell line BAF-B03, the expression of any two of lckF505 (an active form of p56lck), Bcl-2, or c-Myc is sufficient to promote transit of the cell cycle, regardless of the activation state of the third pathway. We also provide evidence that epidermal growth factor receptor signaling may act through the same pathway that involves p56lck. These studies demonstrate a novel approach to dissecting signaling pathways regulating cellular proliferation.

Previous studies demonstrate that p56lck, a member of the src‐family of protein tyrosine kinases (PTKs), can physically associate with the interleukin‐2 (IL‐2) receptor beta chain (IL‐2R beta) and that IL‐2 receptor engagement stimulates p56lck activity. To examine the mechanisms underlying p56lck PTK activation by IL‐2, we established a mouse pro‐B cell line, BAF‐B03, expressing both IL‐2R beta (either the wild‐type or mutant forms) and mouse p56lck at high levels. BAF‐B03 cells expressing a mutant IL‐2R beta chain lacking an ‘acidic’ region of the cytoplasmic domain, previously shown to be essential for association with p56lck, fail to induce p56lck PTK activation upon IL‐2 stimulation. This suggests that the association of p56lck with the IL‐2R beta chain, despite its low stoichiometry, is required for the activation of cellular p56lck PTK upon IL‐2 stimulation. Intriguingly, BAF‐B03 cells expressing an IL‐2R beta chain which lacks a different cytoplasmic region, the ‘serine‐rich’ region, also fail to activate p56lck in response to IL‐2. Hence, physical association of p56lck with the IL‐2R beta chain is not by itself sufficient to permit IL‐2‐mediated regulation of this PTK. Additional experiments suggest that one result of PTK activation is the accumulation of c‐fos and c‐jun transcripts.

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H3K9 methyltransferase G9a is reportedly induced by transforming growth factor-β1 (TGF-β1) and has an important role in the development of epithelial-mesenchymal transposition in cancer cells. Since the transcriptional activity of the Klotho gene is regulated by H3K9 modification, we investigated the effects of G9a on renal fibrosis and klotho expression. G9a levels were significantly upregulated by day 7 in the kidneys of unilateral ureteral-obstructed mice, but this was inhibited by TGF-β1-neutralizing antibody. Administration of G9a small interfering RNA not only decreased α-smooth muscle actin and fibronectin but also increased klotho expression in the ureteral-obstructed mice. Similarly, intraperitoneal injection of BIX01294, a specific inhibitor of G9a, showed beneficial effects on renal fibrosis and klotho expression with decreased monomethylation of H3K9 (me1). In in vitro experiments, BIX01294 also inhibited TGF-β1-induced fibrotic changes and klotho downregulation along with suppressed H3K9me1. In human kidney biopsy specimens, areas of G9a immunostaining correlated positively with H3K9me1 levels, as well as fibrotic markers, but correlated negatively with klotho expression. Thus, TGF-β1-induced G9a has an important role in the progression of renal fibrosis and reduced klotho expression through H3K9me1.

TGF-b1 activity results in methylation of lysine 4 of histone H3 (H3K4) through SET domain-containing lysine methyltransferase 7/9 (SET7/9) induction, which is important for the transcriptional activation of fibrotic genes in vitro. However, in vivo studies utilizing an experimental model of renal fibrosis are required to develop therapeutic interventions that target SET7/9. In this study, we investigated the signaling pathway of TGF-b1-induced SET7/9 expression and whether inhibition of SET7/9 suppresses renal fibrosis in unilateral ureteral obstruction (UUO) mice and kidney cell lines. Among the SET family, SET7/9 was upregulated on days 3 and 7 in UUO mice, and the upregulation was suppressed by TGF-b1 neutralizing antibody. TGF-b1 induced SET7/9 expression via Smad3 in normal rat kidney (NRK)-52E cells. In human kidney biopsy specimens from patients diagnosed with IgA nephropathy and membranous nephropathy, SET7/9 expression was positively correlated with the degree of interstitial fibrosis (r=0.59, P=0.001 in patients with IgA nephropathy; and r=0.58, P,0.05 in patients with membranous nephropathy). In addition, small interfering RNA-mediated knockdown of SET7/9 expression significantly attenuated renal fibrosis in UUO mice. Sinefungin, an inhibitor of SET7/9, also suppressed the expression of mesenchymal markers and extracellular matrix proteins and inhibited H3K4 mono-methylation (H3K4me1) in kidneys of UUO mice. Moreover, sinefungin had an inhibitory effect on TGF-b1-induced a-smooth muscle actin expression and H3K4me1 in both NRK-52E and NRK-49F cells. In conclusion, sinefungin, a SET7/9 inhibitor, ameliorates renal fibrosis by inhibiting H3K4me1 and may be a candidate therapeutic agent.

Sleep bruxism (SB) is a repetitive jaw muscle activity characterized by grinding or clenching of the teeth (Lobbezoo et al., 2013) and it is a possible risk factor for various ailments and disorders in the stomatognathic system, such as dislodgement of dental restorations, tooth fracture, tooth wear, periodontal disease and temporomandibular disorder. Studies have been conducted on the relationships of SB genesis with increase in sympathetic nerve activity, sleep state and genetic factors (

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We have investigated to develop novel vaccines against SARS CoV using cDNA constructs encoding the structural antigen; spike protein (S), membrane protein (M), envelope protein (E), or nucleocapsid (N) protein, derived from SARS CoV. Mice vaccinated with SARS-N or -M DNA using pcDNA 3.1(+) plasmid vector showed T cell immune responses (CTL induction and proliferation) against N or M protein, respectively. CTL responses were also detected to SARS DNA-transfected type II alveolar epithelial cells (T7 cell clone), which are thought to be initial target cells for SARS virus infection in human. To determine whether these DNA vaccines could induce T cell immune responses in humans as well as in mice, SCID-PBL/hu mice was immunized with these DNA vaccines. As expected, virus-specific CTL responses and T cell proliferation were induced from human T cells. SARS-N and SARS-M DNA vaccines and SCID-PBL/hu mouse model will be important in the development of protective vaccines.