Search PubMed⌕ Search

Biomedical subjects

Yumi Matsumura

Publications and source records attributed to Yumi Matsumura.

6 recordsLinked to original sources
PubMed2006

A role for inflammatory mediators in the induction of immunoregulatory B cells.

UV exposure suppresses the immune response to a variety of microbial, fungal, and viral Ags. In addition, UV radiation is a complete carcinogen and the immune suppression induced by UV radiation is a major risk factor for skin cancer induction. In this study, we examined the mechanisms underlying the induction of immune suppression and tolerance induction by UV radiation. Transferring lymph nodes cells from UV-irradiated, FITC-sensitized mice into normal recipients transferred immune tolerance. Contrary to expectations, the cell responsible was an FITC(+), IL-10-secreting, CD19(+), B220(+) B cell. Because the lipid mediator of inflammation, platelet-activating factor (PAF) is released by UV-irradiated keratinocytes and is essential for the induction of immune suppression, we determined its role in tolerance induction. When UV-irradiated mice were injected with PCA 4248, a selective PAF receptor (PAFR) antagonist, transfer of tolerance was suppressed. However, immune suppression was not transferred when FITC(+) cells from the draining lymph nodes of UV-irradiated, PAFR-deficient donor mice were injected into the recipients. Because PCA 4248 also blocks serotonin receptor binding, we measured the effect that blocking both serotonin and PAFR binding has on the transfer of immune suppression. Only when both PAF and serotonin binding were blocked could we inhibit tolerance induction. These data identify a novel function for PAF and serotonin in modulating immune function, the activation of immunoregulatory B cells.

Adoptive Transfer↗
PubMed2006

Platelet-activating factor is crucial in psoralen and ultraviolet A-induced immune suppression, inflammation, and apoptosis.

Psoralen plus UVA (PUVA) is used as a very effective treatment modality for various diseases, including psoriasis and cutaneous T-cell lymphoma. PUVA-induced immune suppression and/or apoptosis are thought to be responsible for the therapeutic action. However, the molecular mechanisms by which PUVA acts are not well understood. We have previously identified platelet-activating factor (PAF), a potent phospholipid mediator, as a crucial substance triggering ultraviolet B radiation-induced immune suppression. In this study, we used PAF receptor knockout mice, a selective PAF receptor antagonist, a COX-2 inhibitor (presumably blocking downstream effects of PAF), and PAF-like molecules to test the role of PAF receptor binding in PUVA treatment. We found that activation of the PAF pathway is crucial for PUVA-induced immune suppression (as measured by suppression of delayed type hypersensitivity to Candida albicans) and that it plays a role in skin inflammation and apoptosis. Downstream of PAF, interleukin-10 was involved in PUVA-induced immune suppression but not inflammation. Better understanding of PUVA's mechanisms may offer the opportunity to dissect the therapeutic from the detrimental (ie, carcinogenic) effects and/or to develop new drugs (eg, using the PAF pathway) that act like PUVA but have fewer side effects.

Animals↗
PubMed2005

[Angioedema].

Angioedema, deep mucocutaneous swelling, usually develops around the eyes and lips but may also affect the hands, feet, and throat. Allergic reactions to medications or foods can cause acute angioedema. Hereditary angioedema is a rare disorder, which is related to low levels or abnormal functioning of C1 inhibitors. Acquired C1 inhibitor deficiency is most frequently associated with B-cell lymphoproliferative disease. Some drugs including angiotensin-converting enzyme inhibitors can cause angioedema. Environmental elements such as pressure on the skin and exercise also can result in angioedema in some individuals. In addition, angioedema sometimes may occur in serum sickness, immune system disorders, or may be associated with eosinophilia.

Angioedema↗
PubMed2004

PIG7/LITAF gene mutation and overexpression of its gene product in extramammary Paget's disease.

To identify cancer-related genes that are involved in the carcinogenesis of extramammary Paget's disease (EMPD), we compared mRNA expression profiles of EMPD lesions and corresponding normal skin using cDNA array. Sixty-eight genes were highly expressed (>5-fold) in EMPD lesions compared to normal skin, and 40 genes were expressed less than one-fifth in EMPD lesions. Among them, PIG7/LITAF mRNA was overexpressed in 3 of 4 EMPD cases. PIG7/LITAF transcription is induced by p53 expression and has been implicated in the p53-induced apoptotic pathway. Since expression of p53 mRNA and p53 protein was not high in any of the 3 EMPD samples compared to the intact skin of the same patient, we analyzed PIG7/LITAF cDNA mutations among 12 EMPD samples (including the former 4) by PCR-SSCP. Three samples showed shifted bands (2 had point mutations leading to amino acid substitutions and 1 had a silent mutation). One sample with amino acid substitution overexpressed PIG7/LITAF mRNA in cDNA array analysis and RT-PCR. PIG7/LITAF mRNA expression is confined to tumor cells in in situ mRNA hybridization analysis. These results indicate that genetic disorder and overexpression of PIG7/LITAF may be involved in EMPD carcinogenesis.

Apoptosis↗
PubMed2002

Signaling of gp34 (OX40 ligand) induces vascular endothelial cells to produce a CC chemokine RANTES/CCL5.

We previously showed that gp34 (OX40 ligand) expressed on vascular endothelial cells is not only involved in adhesion between activated T cells and endothelial cells but also by itself able to transmit intracellular signals leading to expression of c-fos and c-jun mRNA upon OX40 binding. In the present study, we searched for genes that were induced or upregulated by gp34 signaling in human umbilical vein endothelial cells (HUVECs) to define its downstream biological events. HUVECs expressing high levels of gp34 were stimulated with recombinant soluble OX40 or mock control and subjected to analysis using cDNA expression arrays. We found that a CC chemokine RANTES (regulated upon activation, normal T cell expressed and secreted)/CCL5 is one of such inducible genes. Reverse transcriptase-PCR analysis showed that expression of RANTES mRNA was induced after incubation with soluble OX40 and this induction was inhibited by anti-gp34 mAb. We could detect expression of intracellular RANTES protein by flow cytometry in HUVECs stimulated with soluble OX40 as well as fixed OX40 transfectant cells but not those stimulated with mock supernatants or mock transfectant cells. Again, this induction of RANTES protein was inhibited by anti-gp34 mAb. These results clearly indicate that gp34 signaling induces expression of RANTES at both mRNA and protein levels in HUVECs and suggest a possible link between the OX40/gp34 system and RANTES during the process of T cell adhesion to endothelial cells and subsequent extravasation.

Antigens, Surface↗