Biomedical subjects

Motoko Morimoto

Publications and source records attributed to Motoko Morimoto.

7 recordsLinked to original sources

PubMed2006

Functional importance of regional differences in localized gene expression of receptors for IL-13 in murine gut.

IL-13 induces a STAT6-dependent hypercontractility of intestinal smooth muscle that is mediated by binding to the IL-13Ralpha1 component of the type 2 IL-4R that is linked to STAT6. IL-13 also binds to the IL-13Ralpha2 that is not linked to STAT6 and functions to limit the effects of IL-13 in vivo. In this study we assessed the contributions of regional and cellular differences in the distribution of the IL-13R components to the physiological regulation of smooth muscle function in wild-type mice and mice deficient in STAT6 or IL-13Ralpha2. The expression of IL-13 and IL-13Ralpha2 was higher in colon than in small intestine. Laser capture microdissection of specific cell types revealed that the expression of IL-13Ralpha2 was higher in the smooth muscle layer compared with levels in the epithelial cells of the mucosa. In contrast, there was a uniform distribution of IL-13alpha1 in smooth muscle, epithelia, and myenteric neurons. The significant hypercontractility of smooth muscle in mice deficient in IL-13Ralpha2, but not in STAT6, shows the physiological importance of IL-13 binding to IL-13Ralpha2. The pronounced differences in the expression of IL-13Ralpha2 suggest that the gut has developed sophisticated mechanisms for controlling the physiological and pathophysiological activities of IL-13.

Animals↗

PubMed2006

Contribution of 5-HT2A receptor in nematode infection-induced murine intestinal smooth muscle hypercontractility.

BACKGROUND & AIMS: Enteric nematode infection induces a smooth muscle hypercontractility that depends on interleukin (IL)-4 and IL-13 activation of the signal transducer and activator of transcription (STAT) 6. Serotonin (5-HT) is involved in the physiologic regulation of gut function. The present study investigated the contribution of 5-HT and its receptors in nematode-induced intestinal smooth muscle hypercontractility. METHODS: Mice were infected with Nippostrongylus brasiliensis (N brasiliensis) or Heligmosomoides polygyrus (H polygyrus) or injected intravenously with IL-13. Segments of jejunum were suspended in organ baths, and smooth muscle responses to 5-HT were determined in the presence or absence of specific 5-HT antagonists. IL-4, IL-13, and 5-HT receptor messenger RNA expressions were determined by real-time quantitative polymerase chain reaction. RESULTS: 5-HT evoked a modest contraction of smooth muscle in wild-type (WT) mice that was unaltered by the 5-HT2A antagonist ketanserin. N brasiliensis infection induced a smooth muscle hypercontractility to 5-HT that was abolished by 5-HT(2A) antagonists but not by other 5-HT antagonists. Infection-induced up-regulation of 5-HT2A expression was correlated with the smooth muscle hypercontractility to 5-HT. The infection-induced up-regulation of 5-HT2A in WT mice was observed also in IL-4(-/-) mice but was not seen in IL-13(-/-) or STAT6(-/-) mice. In addition, smooth muscle responses to 5-HT and 5-HT2A expression in WT mice were also enhanced by IL-13 or H polygyrus infection. CONCLUSIONS: These data show that 5-HT2A is one of the molecules downstream from STAT6 activation that mediates changes in smooth muscle function. 5-HT2A represents a novel therapeutic target for modulating immune-mediated effects on intestinal motility.

Animals↗

PubMed2005

Immune regulation of protease-activated receptor-1 expression in murine small intestine during Nippostrongylus brasiliensis infection.

Infection with gastrointestinal nematodes exerts profound effects on both immune and physiological responses of the host. Helminth infection induces a hypercontractility of intestinal smooth muscle that is dependent on the Th2 cytokines, IL-4 and IL-13, and may contribute to worm expulsion. Protease-activated receptors (PARs) are expressed throughout the gut, and activation of PAR-1 was observed in asthma, a Th2-driven pathology. In the current study we investigated the physiologic and immunologic regulation of PAR-1 in the murine small intestine, specifically 1) the effect of PAR-1 agonists on small intestinal smooth muscle contractility, 2) the effects of Nippostrongylus brasiliensis infection on PAR-1 responses, 3) the roles of IL-13 and IL-4 in N. brasiliensis infection-induced alterations in PAR-1 responses, and 4) the STAT6 dependence of these responses. We demonstrate that PAR-1 activation induces contraction of murine intestinal smooth muscle that is enhanced during helminth infection. This hypercontractility is associated with an elevated expression of PAR-1 mRNA and protein. N. brasiliensis-induced changes in PAR-1 function and expression were seen in IL-4-deficient mice, but not in IL-13- or STAT6-deficient mice, indicating the dependence of IL-13 on the STAT6 signaling pathway independent of IL-4.

Animals↗

PubMed2005

Localized multigene expression patterns support an evolving Th1/Th2-like paradigm in response to infections with Toxoplasma gondii and Ascaris suum.

Human infectious diseases have been studied in pigs because the two species have common microbial, parasitic, and zoonotic organisms, but there has been no systematic evaluation of cytokine gene expression in response to infectious agents in porcine species. In this study, pigs were inoculated with two clinically and economically important parasites, Toxoplasma gondii and Ascaris suum, and gene expression in 11 different tissues for 20 different swine Th1/Th2-related cytokines, cytokine receptors, and markers of immune activation were evaluated by real-time PCR. A generalized Th1-like pattern of gene expression was evident in pigs infected with T. gondii, along with an increased anti-inflammatory gene expression pattern during the recovery phase of the infection. In contrast, an elevated Th2-like pattern was expressed during the period of expulsion of A. suum fourth-stage larvae from the small intestine of pigs, along with low-level Th1-like and anti-inflammatory cytokine gene expression. Prototypical immune and physiological markers of infection were observed in bronchial alveolar lavage cells, small intestinal smooth muscle, and epithelial cells. This study validated the use of a robust quantitative gene expression assay to detect immune and inflammatory markers at multiple host tissue sites, enhanced the definition of two important swine diseases, and supported the use of swine as an experimental model for the study of immunity to infectious agents relevant to humans.

Animals↗

PubMed2004

Peripheral CD4 T cells rapidly accumulate at the host: parasite interface during an inflammatory Th2 memory response.

Memory peripheral Th2 immune responses to infectious pathogens are not well studied due to the lack of suitable models and the difficulty of assessing Th2 cytokine expression at sites of inflammation. We have examined the localized immune response to a nematode parasite that encysts in the small intestine. An unexpected architecture was observed on day 4 of the memory response, with granulocytes and macrophages infiltrating the cyst and CD4(+), TCR-alphabeta(+) T cells surrounding the cyst. Laser capture microdissection analysis showed a pronounced CD4-dependent Th2 cytokine pattern at the cyst region only during the memory response, demonstrating that the Th2 memory response is readily distinguished from the primary response by the rapid accumulation of Th2 effector cells at the host:parasite interface.

Administration, Oral↗

PubMed2004

Requirements for the development of IL-4-producing T cells during intestinal nematode infections: what it takes to make a Th2 cell in vivo.

Components of the type 2 immune response may mediate host protection against both helminthic parasites and harmful allergic responses. A central player in this response is the T-helper 2 (Th2) effector cell, which produces interleukin (IL)-4, IL-5, IL-13, and other Th2 cytokines during the primary and memory response. Specific aspects of the parasite that trigger Th2-cell differentiation are not yet defined. Furthermore, the cell types and cell surface and secreted molecules that provide the immune milieu required for the development of Th2 effector cells and also Th2 memory cells are not well understood. They will probably vary with the particular helminth or other antigen inducing the Th2 response. We have used third stage larvae of intestinal nematode parasites as adjuvants to promote naïve nonparasite antigen-specific T cells to differentiate into Th2 cells. This model system avoids possible parasite antigen-specific T-cell clones or cross-reactive memory T cells that may preferentially differentiate into Th2 effector cells during the course of infection and confound the stereotypical components of parasite-induced Th2 cell differentiation. We have found that these parasites have a potent adjuvant effect and have used our model system to begin to investigate the events that lead to the development of polarized Th2 cells in vivo.

Animals↗

PubMedDate not supplied

Ascaris suum: cDNA microarray analysis of 4th stage larvae (L4) during self-cure from the intestine.

There is spontaneous cure of a large portion of Ascaris suum 4th-stage larvae (L4) from the jejunum of infected pigs between 14 and 21 days after inoculation (DAI). Those L4 that remain in the jejunum continue to develop while those that have moved to the ileum are eventually expelled from the intestines. Although increases in intestinal mucosal mast cells and changes in local host immunity are coincidental with spontaneous cure, the population of L4 that continue to develop in the jejunum may counteract host protective mechanisms by the differential production of factors related to parasitism. To this end, a cDNA library was constructed from L4 isolated from pig jejunum at 21 DAI, and 93% of 1920 original clones containing a single amplicon in the range 400-1500 bp were verified by gel electrophoresis and printed onto glass slides for microarray analysis. Fluorescent probes were prepared from total RNA isolated from: (1) 3rd stage-larvae from lung at 7 DAI, (L3); (2) L4 from jejunum at 14 DAI (L4-14-J); (3) L4 from jejunum at 21 DAI (L4-21-J); (4) L4 from ileum at 21 DAI (L4-21-I, and; (5) adults (L5). Cy3-labeled L3, L4-14-J, L4-21-I and L5 cDNA, and Cy5-labeled L4-21-J cDNA were simultaneously used to screen the printed arrays containing the L4-21-J-derived cDNA library. Several clones showed consistent differential gene expression over two separate experiments and were grouped into 3 distinct transcription patterns. The data showed that sequences from muscle actin and myosin, ribosomal protein L11, glyceraldehyde-3-phosphate dehydrogenase and the flavoprotein subunit of succinate dehydrogenase were highly expressed in L4-21-J, but not in L4-21-I; as were a collection of un-annotated genes derived from a worm body wall-hypodermis library, and a testes germinal zone tissue library. These results suggest that only actively developing A. suum L4 are destined to parasitize the host and successfully neutralize host protective responses.

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