Role of substance P in hypersensitivity reactions induced by paclitaxel, an anticancer agent

The role of substance P in adverse pulmonary reactions induced by an anticancer agent paclitaxel was investigated in rats and humans who undertook post-operative chemotherapy for ovarian cancer. In rats, paclitaxel caused a marked plasma extravasation and edema in lungs with a concomitant decrease in arterial partial oxygen pressure, which were reversed by an NK1 antagonist LY303870. Substance P level in rat plasma and bronchoalveolar lavage fluid increased after paclitaxel injection. In 13 patients, plasma level of substance P but not histamine significantly (P < 0.05) increased during paclitaxel infusion. Therefore, substance P rather than histamine may be involved in paclitaxel hypersensitivity.     

Tacrolimus-Induced Neurotoxicity and Nephrotoxicity Is Ameliorated by Administration in the Dark Phase in Rats

1. Tacrolimus, a potent immunosuppressant, induces impaired renal function and neurological complications. We investigated the influence of dosing time on the neurotoxicity, nephrotoxicity, and immunosuppressive effect of tacrolimus in rats. 2. The repeated injection of tacrolimus in the light phase (8:00) produced a significantly greater increase than that in the dark phase (20:00) in the duration of harmine-induced tremors and in the blood urea nitrogen (BUN) concentration in rats. An immunosuppressive effect of tacrolimus on the xenotransplantation of mouse-to-rat skin grafts was apparent in the dark phase but not in the light phase. 3. The dosing time-dependent pharmacokinetic results were not observed when tacrolimus concentrations in rat whole blood were measured after a single or repeated injection in the light or dark phase. 4. These findings suggest that treatment in the active phase of the diurnal cycle ameliorates neurotoxicity and nephrotoxicity while maintaining the immunosuppressive effect of tacrolimus. The present findings have important implications for therapeutic approaches to avoid tacrolimus-induced neurotoxicity and nephrotoxicity.     

Hes binding to STAT3 mediates crosstalk between Notch and JAK-STAT signalling

Although the Notch and JAK-STAT signalling pathways fulfill overlapping roles in growth and differentiation regulation, no coordination mechanism has been proposed to explain their relationship. Here we show that STAT3 is activated in the presence of active Notch, as well as the Notch effectors Hes1 and Hes5. Hes proteins associate with JAK2 and STAT3, and facilitate complex formation between JAK2 and STAT3, thus promoting STAT3 phosphorylation and activation. Furthermore, suppression of endogenous Hes1 expression reduces growth factor induction of STAT3 phosphorylation. STAT3 seems to be essential for maintenance of radial glial cells and differentiation of astrocytes by Notch in the developing central nervous system. These results suggest that direct protein-protein interactions coordinate cross-talk between the Notch-Hes and JAK-STAT pathways.     

Intact glycation end products containing carboxymethyl-lysine and glyoxal lysine dimer obtained from synthetic collagen model peptide

Advanced glycation end products (AGE) are accumulated in human tissues when long-lived proteins are glycated due to hyperglycemia and/or aging. In this study, we synthesized a collagen model peptide, Ac-(Pro-Hyp-Gly)(5)-Pro-Lys-Gly-(Pro-Hyp-Gly)(5)-Ala-NH(2) to investigate intact AGEs in peptides. The peptide formed a stable triple helix structure, and was subjected to glycation reactions with glucose, ribose and glyoxal. Besides carboxymethyl-lysine in the peptide, a conjugated form linked with glyoxal lysine dimer (GOLD) was detected upon treatment with glyoxal. This is the first example of intact glycation-derived dimers of peptides retaining intrinsic protein structures.     

Regulation of Chk2 gene expression in lymphoid malignancies: involvement of epigenetic mechanisms in Hodgkin's lymphoma cell lines

The tumor suppressor Chk2 kinase plays crucial roles in regulating cell-cycle checkpoints and apoptosis following DNA damage. We investigated the expression levels of the genes encoding Chk2 and several cell-cycle regulators in nine cell lines from lymphoid malignancies, including three Hodgkin's lymphoma (HL) lines. We found that all HL cell lines exhibited a drastic reduction in Chk2 expression without any apparent mutation of the Chk2 gene. However, expression of Chk2 in HL cells was restored following treatment with the histone deacetylase inhibitors trichostatin A (TsA) and sodium butyrate (SB), or with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5Aza-dC). Chromatin-immunoprecipitation (Chip) assays revealed that treatment of HL cells with TsA, SB or 5Aza-dC resulted in increased levels of acetylated histones H3 and H4, and decreased levels of dimethylated H3 lysine 9 at the Chk2 promoter. These results indicate that expression of the Chk2 gene is downregulated in HL cells via epigenetic mechanisms.     

Studies using leukemia inhibitory factor (LIF) knockout mice and a LIF adenoviral vector demonstrate a key anti-inflammatory role for this cytokine in cutaneous inflammation

Previous work has implicated the cytokine leukemia inhibitory factor (LIF) in cutaneous inflammation, although results have differed as to whether LIF is pro- or anti-inflammatory in this setting. We examined edema, inflammatory cell infiltration, and cytokine responses following CFA injection in the adult mouse footpad. Inflammatory cell infiltration and edema are significantly enhanced when CFA is injected in LIF knockout mice as compared with injection of wild-type littermates. Moreover, local injection of an adenoviral vector encoding LIF suppresses both measures of inflammation. In contrast, injection of an adenoviral vector encoding beta-galactosidase has no discernable effect on inflammation. In addition, comparison of the CFA responses in LIF knockout vs wild-type skin reveals that LIF is an important regulator of IL-1beta, IL-6, IL-7, IL-2Ralpha, and IFN-gamma in cutaneous inflammation. These and our previous data indicate that both endogenous and exogenous LIF are anti-inflammatory in the CFA model and that LIF is a key regulator of the cytokine cascade. The results also indicate that adenoviral gene delivery can be an effective therapeutic approach in this paradigm.     

Simultaneous arterial calcium dynamics and diameter measurements: application to myoendothelial communication

The goal of the present study was to analyze the intercellular calcium communication between smooth muscle cells (SMCs) and endothelial cells (ECs) by simultaneously monitoring artery diameter and intracellular calcium concentration in a rat mesenteric arterial segment in vitro under physiological pressure (50 mmHg) and flow (50 microl/min) in a specially developed system. Intracellular calcium was expressed as the fura 2 ratio. The diameter was measured using a digital image acquisition system. Stimulation of SMCs with the alpha(1)-agonist phenylephrine (PE) caused not only an increase in the free intracellular calcium concentration of the SMCs as expected but also in the ECs, suggesting a calcium flux from the SMCs to the ECs. The gap junction uncoupler palmitoleic acid greatly reduced this increase in calcium in the ECs on stimulation of the SMCs with PE. This indicates that the signaling pathway passes through the gap junctions. Similarly, although vasomotion originates in the SMCs, calcium oscillates in both SMCs and ECs during vasomotion, suggesting again a calcium flux from the SMCs to the ECs.     

Association of immature hypophosphorylated protein kinase cepsilon with an anchoring protein CG-NAP

Protein kinase C (PKC) family requires phosphorylation of itself to become competent for responding to second messengers. Much attention has been focused on elucidating the role of phosphorylation in PKC activity; however, it remains unknown where this modification takes place in the cells. This study examines whether anchoring protein is involved in the regulation of PKC phosphorylation. A certain population of PKC epsilon in rat brain extracts as well as that expressed in COS7 cells was associated with an endogenous anchoring protein CG-NAP (centrosome and Golgi localized PKN- associated protein). Pulse chase experiments revealed that the associated PKC epsilon was an immature species at the hypophosphorylated state. In vitro binding studies confirmed that non- or hypophosphorylated PKC epsilon directly bound to CG-NAP via its catalytic domain, whereas sufficiently phosphorylated PKC epsilon did not. PKC epsilon mutant at a potential phosphorylation site of Thr-566 or Ser-729 to Ala, possessing almost no catalytic activity, was associated and co-localized with CG-NAP at Golgi/centrosome area. On the other hand, wild type and a phosphorylation-mimicking mutant at Thr-566 were mainly distributed in cytosol and represented second messenger-dependent catalytic activation. These results suggest that CG-NAP anchors hypophosphorylated PKCepsilon at the Golgi/centrosome area during maturation and serves as a scaffold for the phosphorylation reaction.     

Cloning of vitellogenin cDNA of the American cockroach, Periplaneta americana (Dictyoptera), and its structural and expression analyses

A cDNA expression library constructed from poly (A)(+) RNA prepared from vitellogenic female fat body cells of the American cockroach, Periplaneta americana (Dictyoptera) was screened using a polyclonal antiserum against the 100-kD polypeptide(s) from the egg extract. A partial Vg cDNA clone was obtained and sequenced. The 5' end portion of the cDNA was then obtained by the RACE method, cloned, and sequenced. The combined complete Vg cDNA was 5,854 bp long and contained a single ORF encoding 1,896 amino acids. The entire deduced amino acid sequence was aligned confidently with those of the known insect Vgs. A GL/ICG motif, a number of cysteines at conserved locations following this motif, and a DGXR motif upstream of the GL/ICG motif were present near the C-terminal. The chemically determined N-terminal amino acid sequence of the 170-kD polypeptide from the egg extract completely matched the deduced sequence starting from just after one of the consensus (RXXR) cleavage sites, indicating the occurrence of post-translational cleavage in the fat body cells. The Vg gene begins to be expressed in the 2-day-old adult female fat body cells but is never expressed in ovaries or in male fat body cells. Hemolymph Vg was first detected by immunoblotting in 4-day-old adult females, 2 days after the beginning of gene expression. Western blot analysis of major yolk polypeptides in nine cockroach species belonging to the two superfamilies, Blattoidea and Blaberoidea, using the antisera against P. americana major yolk polypeptides showed that the similarities in Vn antigenicity are basically limited to within a superfamily.