Yoshiharu Yamamura

Local secretion of corticotropin-releasing hormone by enterochromaffin cells in human colon

BACKGROUND/AIMS Corticotropin-releasing hormone (CRH) is a regulator of the hypothalamic-pituitary-adrenal axis and a coordinator of the gastrointestinal response to stress. In addition to its central effects, CRH has peripheral effects on the immune system. CRH is present in several human tissues, such as the brain, spinal cord, adrenal medulla, lung, liver, peripheral blood leukocytes, as well as the gastrointestinal tract. The current study examined the local production of CRH in the normal human colon. METHODS Normal human colonic tissues obtained by endoscopic biopsy were immunostained with anti-CRH and anti-5-hydroxytryptamine antibody and analyzed for CRH messenger (m)RNA by a reverse-transcribed polymerase chain reaction method and by in situ hybridization. RESULTS Immunoreactive CRH and CRH mRNA were detected in the colonic mucosal cells in the neighborhood of the base of the crypts. The mucosal cells that expressed CRH mRNA also immunostained with anti-5-hydroxytryptamine antibody. CONCLUSIONS Normal human colonic mucosal enterochromaffin cells produce CRH. CRH in the colonic mucosa may play a role in the modulation of the intestinal immune system and/or other gastrointestinal functions basally during stressful conditions.

Treatment of malignant ascites and pleurisy by a streptococcal preparation OK-432 with fresh frozen plasma—a mechanism of polymorphonuclear leukocyte (PMN) accumulation

A single injection of a streptococcal preparation, OK-432, with fresh frozen plasma (FFP) (or fresh human serum) into the peritoneal or pleural cavity for the treatment of malignant ascites or pleurisy resulted in a complete reduction of ascitic fluid or pleural effusion in 5 out of 11 patients. FFP was used a further source of complement for the effective accumulation of antitumor polymorphonuclear leukocytes (PMNs) by complement-derived chemotactic factors in the cavity. C5a increased in the fluids 3-9 h after the injection and preceded a massive increase in PMNs. C1 inhibitor (C1INH) and C3b inactivator (C3bINA) decreased in several cases 6 h after the treatment. Chemotactic arachidonic acid metabolites, thromboxane B2(TXB2) as a characteristics of TXA2, and leukotriene B4(LTB4) also increased at the same time even in cases where C5a changed only minimally, and may play a role in accumulating antitumor PMNs in the cavity.

PSK and OK-432-induced immunomodulation of inducible nitric oxide (NO) synthase gene expression in mouse peritoneal polymorphonuclear leukocytes and NO-mediated cytotoxicity.

Abstract We investigated whether PSK (a polysaccharide from the mycelia of Coriolus versicolor) or OK-432 (a streptococcal preparation) can up-regulate inducible nitric oxide synthase (iNOS) gene expression and nitric oxide (NO) production in mouse peritoneal polymorphonuclear leukocytes (PMNs). Six hrs after intraperitoneal injection of mice with PSK (2500 μg/mouse) or OK-432 (100 μg/mouse), mouse peritoneal PMNs were restimulated with PSK (500 μg/ml) or OK-432 (10 μg/ml) plus 100 U/ml of mouse interferon-gamma (IFN-γ) in vitro. Northern blot analysis showed strong synergism between both PSK and OK-432 and IFN-γ for the induction of iNOS gene expression. NO production by PMNs was increased up to 20 μM (2 μM/106 PMNs/24 hrs) as measured by the Griess reagent method when PMNs were restimulated with PSK or OK-432 plus IFN-γ for 24 hrs, although tumor cell killing was not detected. NO concentrations of more than 80 μM were required for P815 tumor cell killing. These results suggest that PMNs produce NO after stimulation with PSK or OK-432 in combination with IFN-γ and may regulate the immune system in vivo, although the NO production induced by these agents is insufficient for tumor cell killing in vitro.

Effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on cytotoxicity of PSK-induced peritoneal polymorphonuclear leukocytes (PMNs)

We investigated whether recombinant human granulocyte colony-stimulating factor (rhG-CSF) en hanced the cytotoxicity of PSK-induced polymorphonuclear leukocytes (PMNs) in the peritoneal cavity. Male C3H/He mice, 8- to 10-week-old, received single subcutaneous (s.c.) or intraperitoneal (i.p.) injection of 2.5 µg/animal of rhG-CSF at different time points before or after an i.p. administration of PSK. In other experiments, mice were s.c. or i.p. treated with the same dosage of rhG-CSF every day for 7 or 14 consecutive days and i.p. injected with 2.5 mg/animal of PSK on the last day. Peritoneal PMNs were harvested 6 hrs after the administration of PSK and purified to more than 95% by Ficoll-Paque for in vitro cytotoxic assay.In vitro cytotoxic assays with51Cr labeled MM46 mammary carcinoma cells were added with 5–20 µg/ml of Nocardia rubra cell wall skeleton (N-CWS) at the beginning of the assay to augment the cytotoxic activity of PMNs.In vitro addition of rhG-CSF to the assay did not enhance the cytotoxicity of PSK-induced PMNs. However, the cytotoxicity was signifi cantly increased when rhG-CSF was s.c. administered 12 hrs before a PSK injection or 2 or 5 hrs after that. On the other hand, the cytotoxicity was rather weak when mice s.c. or i.p. received consecutive injections of rhG-CSF. This cytotoxicity may be mediated by H2O2, since H2O2 production of PMNs during the cytotoxic assay appears to correlate with the levels of cytotoxicity under suppressed H2O2 generation by catalase or enhanced generation by rhG-CSF. These results suggest that rhG-CSF augments the cytotoxicity of PSK-induced PMNs when administeredin vivo timely.

In vitro augmentation of cytotoxicity by N-CWS in peritoneal polymorphonuclear leukocytes (PMNs) induced by PSK, OK-432 or N-CWS

Peritoneal polymorponuclear leukocytes (PMNs) were collected from the peritoneal cavity of C3H/He mice 6 hrs after intraperitoneal (i.p.) injection of 2.5 mg/head of PSK, 1 KE (100 µg)/head of OK-432 or 200 µg/head ofNocardia rubra cell wall skeleton (N-CWS). Withoutin vitro stimulation, these PMNs did not show cytotoxicity to syngeneic MM46 mammary carcinoma cells in51Cr release assay. Cytotoxicity of these PMNs was augmented by the addition of 25 µg/ml of N-CWS but not of PSK or OK-432 to cultures for the assay at the beginning of the culture. H2O2 production of PSK-induced PMNs was increased by thein vitro addition of 25 µg/ml of N-CWS but not of PSK. These results suggest that PSK as well as OK-432 and N-CWS can induce PMNs capable of responding further to N-CWS as the second stimulant.

Recombinant human granulocyte colony-stimulating factor augments cytotoxicity of OK-432-induced polymorphonuclear leukocytes

Polymorphonuclear leukocytes (PMNs) recovered from the peritoneal cavity of mice treated with the streptococcal preparation OK-432, exhibited strong cytotoxicity after the in vitro addition of Nocardia rubra cell wall skeleton (N-CWS). In this study, we investigated whether recombinant human granulocyte colony-stimulating factor (rhG-CSF) could augment the cytotoxicity of OK-432-induced PMNs after the addition of N-CWS in vitro. PMNs recovered from the peritoneal cavity of 8- to 10-week-old, male C3H/He mice induced by intraperitoneal (i.p.) injection of 50 KE/kg (1 KE = 0.1 mg) of OK-432 were used in a 51Cr release assay against MM46 mammary carcinoma cells. While addition of rhG-CSF in vitro did not augment the cytotoxicity of OK-432-induced PMNs, marked augmentation of the cytotoxicity of OK-432-induced PMNs was observed following a single subcutaneous (s.c.) or i.p. injection of 125 micrograms/kg of rhG-CSF. The effect of in vivo administered rhG-CSF was dependent on the timing of the injection with respect to OK-432 administration and differed from s.c. or i.p. injections. Interestingly, the cytotoxicity of OK-432-induced PMNs was rather weak following consecutive s.c. or i.p. administration of rhG-CSF for 7-14 days. H2O2 is likely involved in mediating the cytotoxicity of OK-432-induced PMNs since activity was significantly reduced by the in vitro addition of low concentration of catalase. Generation of H2O2 by the PMNs correlated with cytotoxicity. These results suggest that in vivo administration of rhG-CSF augments the cytotoxicity of OK-432-induced PMNs in a time dependent fashion and that H2O2 plays an important role in mediating their cytotoxicity.

Morphological study of cytotoxicity produced by PSK-induced polymorphonuclear leukocytes (PMNS) and Nocardia rubra cell wall skeleton

The morphologic changes in PMNs induced by an i.p. injection of PSK, a polysaccharide from the mycelia ofCoriolus versicolor, and tumor cells undergoing cell death, were evaluated by immunohistochemical staining and electron microscopy. Male C3H/He mice, 8–10-weeks old, received an i.p. injection of 125 mg/kg of PSK. Their PMNs were obtained 6 h after the PSK injection by peritoneal lavage. N-CWS (Nocardia rubra cell wall skeleton) was added at the start of the chromium release assay using the MM46 mammary carcinoma cell line, which is syngeneic to C3H/He mice, as target cells. During the cytotoxic assay, the cells were fixed at various time points. The MM46 cells expressed ICAM-1 while the PMNs expressed both ICAM-1 and LFA-1 as determined by immunohistochemical staining and immunoelectron microscopy using anti-ICAM-1 and anti-LFA-1 antibodies. PMNs with ruffle-like microvilli adhered to the MM46 tumor cells 30 min after the addition of N-CWS. Immunoelectron microscopic findings suggested that the adhesion molecules were LFA-1 on the PMNs and ICAM-1 on the MM46 tumor cells, but cell fusion between the PMNs and tumor cells was not observed. The MM46 tumor cells gradually lost their microvilli, which showed cell damage, and died 6–7 h after the addition of the N-CWS. This time course of tumor cell death is compatible with the results of the cytotoxic assay. Pretreatment of PMNs by anti-LFA-1 antibody suppressed % lysis of MM46 tumor cells from 90 % to 10 %(p<0.01). These data suggest that adhesion molecule on the surface of PMNs such as LFA-1 might play an important role on signal transduction of these PMNs cytotoxic function in this experimental system.