Factors influencing lifespan dependency on agricultural crops by brown bears

Landscape and Ecological Engineering - Investigating factors underlying human-wildlife conflicts in agricultural landscapes is important for both preventing crop damage and wildlife conservation....     

STAT5 induces macrophage differentiation of M1 leukemia cells through activation of IL-6 production mediated by NF-kappaB p65

We recently demonstrated that STAT5 can induce a variety of biological functions in mouse IL-3-dependent Ba/F3 cells; STAT5-induced expression of pim-1, p21(WAF/Cip1), and suppressor of cytokine signaling-1/STAT-induced STAT inhibitor-1/Janus kinase binding protein is responsible for induction of proliferation, differentiation, and apoptosis, respectively. In the present study, using a constitutively active STAT5A (STAT5A1*6), we show that STAT5 induces macrophage differentiation of mouse leukemic M1 cells through a distinct mechanism, autocrine production of IL-6. The supernatant of STAT5A1*6-transduced cells contained sufficient concentrations of IL-6 to induce macrophage differentiation of parental M1 cells, and STAT3 was phosphorylated on their tyrosine residues in these cells. Treatment of the cells with anti-IL-6 blocking Abs profoundly inhibited the differentiation. We also found that the STAT5A1*6 transactivated the IL-6 promoter, which was mediated by the enhanced binding of NF-kappaB p65 (RelA) to the promoter region of IL-6. These findings indicate that STAT5A cooperates with Rel/NF-kappaB to induce production of IL-6, thereby inducing macrophage differentiation of M1 cells in an autocrine manner. In summary, we have shown a novel mechanism by which STAT5 induces its pleiotropic functions. Cytokines     

Adhesive Property of <Emphasis Type="Italic">Bifidobacterium lactis</Emphasis> LKM512 and Predominant Bacteria of Intestinal Microflora to Human Intestinal Mucin

The adhesive property to the intestinal mucin of Bifidobacterium lactis LKM512, B. longum, B. breve, B. bifidum, B. adolescentis, B. infantis, Bacteroides vulgatus, Bacteroides distasonis, Eubacterium aerofaciens, Clostridium perfringens, Escherichia coli, and Lactobacillus acidophilus were examined. Adhesive rate of LKM512 to the mucin was significantly (p < 0.05, 0.01, or 0.001) stronger than the other strains from 2 to 100 time. Though the adhesive property of many strains was almost same to the mucin of 20-year-old and 50-year-old generations, in case of 4-month-old was different. Adhesive inhibitory effect of C. perfringens to the mucin by LKM512 was examined. Under the condition that LKM512 was 10⁸/ml and that C. perfringens was 10⁶/ml, adhesion of C. perfringens to the mucin was inhibited at 99.6%, when LKM512 adhered in advance. There was the strong inhibition of adhesion at 74.0%, when C. perfringens adhered to mucin in advance. Thus, LKM512 can inhibit the adhesion of harmful bacteria to the intestinal mucin, the possibility of using as a probiotic strain has to be verified.     

Mycophenolic acid as a latent agonist of PPARgamma

Mycophenolic acid (MPA), known as an inhibitor of inosine monophosphate dehydrogenase (IMPDH), was found to inhibit the differentiation of 3T3-L1 pre-adipocytes into mature adipocytes. Although the effect of MPA was attributed to inhibition of IMPDH, we uncovered a hidden biological property of MPA as an agonist of peroxisome proliferator activated receptor gamma (PPARgamma).     

Catalytic antibody light chain capable of cleaving a chemokine receptor CCR-5 peptide with a high reaction rate constant

A monoclonal antibody (MAb), ECL2B-2, was obtained by immunizing a peptide possessing a part of a sequence of a chemokine receptor, CCR-5, which is present as a membrane protein on the macrophage surface, and which plays an important role in human immunodeficiency virus (HIV) infection. From the DNA and the deduced amino acid sequences of the light and heavy chains of ECL2B-2 MAb, molecular modeling was conducted to calculate the steric conformation of the antibody. Modeling suggested that the structure of ECL2B-2 could possess one or two catalytic triad(s), composed of Asp(1), Ser(27a) (or Ser(27e)), and His(93) (or His(27d)), in the light chain of ECL2B-2. The three amino acid residues, Asp(1), Ser(27a), and His(93), are identical to those of catalytic antibody light chains such as VIPase and i41SL1-2. The light chain of ECL2B-2 MAb degraded the antigenic peptide CCR-5 within about 100 h. Surprisingly, the light chain had a very high catalytic reaction rate constant (k(cat)) of 2.23 min(-1), which is greater by factors of tens to hundreds than those of natural catalytic antibodies obtained previously. The heavy chain of ECL2B-2 MAb, which has no catalytic triad because of a lack of His residue, did not degrade the CCR-5 peptide.     

Pathogenicity of catalytic antibodies: catalytic activity of Bence Jones proteins from myeloma patients with renal impairment can elicit cytotoxic effects

Some Bence Jones proteins (BJPs) can display catalytic activity. Although the catalytic activity of BJPs might be associated with the pathogenesis of disease, this relationship has not yet been established. We tested the effects of seven BJPs on LLC-PK1 cells to assess their pathogenicity. Two out of the seven BJPs showed cytotoxic activity, as assessed by microscopic analysis, the WST method and TUNEL staining. Moreover, the cytotoxic BJPs were excreted by patients who presented with renal impairment. The cytotoxic BJPs displayed 20- to 40-fold higher catalytic activities (kcat of 3.5-2.2 min(-1)) in hydrolyzing a chromogenic substrate compared to the other BJPs. By treating the cytotoxic BJPs with diisopropylfluorophosphate, they lost not only their catalytic activity, but also the cytotoxic effects. These results indicate a direct link between cytotoxicity and the catalytic activity of the BJPs. The catalytic activity of BJPs contributes to the pathogenesis, as well as to development, of symptoms of multiple myeloma. Inhibition of the catalytic activity of BJPs may form the basis of a novel treatment for multiple myeloma patients with renal dysfunction.     

LPS-induced IL-6, IL-8, VCAM-1, and ICAM-1 expression in human lymphatic endothelium.

We have previously reported the TLR4 expression in human intestinal lymphatic vessels. In the study here, microarray analysis showed the expression of the TLR4, MD-2, CD14, MyD88, TIRAP, TRAM, IRAK1, and TRAF6 genes in cultured human neonatal dermal lymphatic microvascular endothelial cells (LEC). The microarray analysis also showed that LEC expressed genes of IL-6, IL-8, VCAM-1, and ICAM-1, and the real-time quantitative PCR analysis showed that mRNA production was increased by lipopolysaccharide (LPS). The LPS-induced IL-6, IL-8, VCAM-1, and ICAM-1 production in LEC was suppressed by the introduction of TLR4-specific small interfering RNA, and also by anti-TLR4, nobiletin, and CAPE pretreatment. These findings suggest that LEC has TLR4-mediated LPS recognition mechanisms that involve at least activation of NF-kappaB, resulting in increased expression of IL-6, IL-8, VCAM-1, and ICAM-1. Both the LPS effect on the gene expression and also the suppression by nobiletin and CAPE pretreatment on the protein production were larger in IL-6 and in VCAM-1 than in IL-8 and in ICAM-1 in LEC. The signal transduction of NF-kappaB and AP-1-dependent pathway may be more critical for the expression of IL-6 and VCAM-1 than that of IL-8 and ICAM-1 in LEC.     

Catalytic features and eradication ability of antibody light-chain UA15-L against Helicobacter pylori

We have successfully developed a catalytic antibody capable of degrading the active site of the urease of Helicobacter pylori and eradicating the bacterial infection in a mouse stomach. This monoclonal antibody UA15 was generated using a designed recombinant protein UreB, which contained the crucial region of the H. pylori urease beta-subunit active site, for immunization. The light chain of this antibody (UA15-L) by itself showed a proteolytic activity to substantially degrade both UreB and the intact urease. Oral administration of UA15-L also significantly reduced the number of H. pylori in a mouse stomach. This is the first example of a monoclonal catalytic antibody capable of functioning in vivo, and such an antibody may have a therapeutic utility in the future.