Spontaneous development of dermatitis in DS-Nh mice under specific pathogen-free conditions.

Spontaneous development of dermatitis in DS-Nh mice under specific pathogen-free conditions was examined to verify the hypothesis [Exp. Anim. 46: 225-229, 1997] that Stapylococcus aureus (S. aureus) infection is causally associated with the dermatitis. Observation of the mice up to 28 weeks of age indicated that obvious dermatitis does occur under S. aureus-free conditions, though the incidence was low (six of 42 females and two of 90 males). Skin lesions in the absence of this bacterium showed histological changes very similar to those that can be observed under conventional conditions. In addition, hyperproduction of serum IgE was demonstrated in the dermatitis-positive mouse. These findings suggested that the dermatitis is triggered by IgE-mediated allergic reactions.     

Role of aquaporin 5 in antigen‐induced airway inflammation and mucous hyperproduction in mice

Airway inflammation and mucus hyperproduction play the central role in the development of asthma, although the mechanisms remain unclear. The aquaporin (AQP)‐5 may be involved in the process due to its contribution to the volume of liquid secreted from the airways. The present study firstly found the overexpression of AQP5 in the airway epithelium and submucosal glands of asthmatics. Furthermore, we aimed at evaluating the role of AQP5 in airway inflammation and mucous hyperproductions during chronic allergic responses to house dust mite (HDM). Bronchoalveolar lavage levels of interleukin (IL)‐2, IL‐4, IL‐10, interferon‐γ and Mucin 5AC (MUC5AC), and number of peribronchial and perivascular cells were measured in AQP5 wild‐type and AQP5 knockout (KO) mice. We found that HDM induced airway inflammation, lung Th2 cell accumulation and mucin hypersecretion in C57BL/6 mice rather than AQP5 KO mice. Expression of MUC5AC and MUC5B proteins and genes in the lung tissue was significantly lower in AQP5 KO mice. Thus, our results implicate involvement of AQP5 in the development of airway inflammation and mucous hyperproduction during chronic asthma.     

Genetic analysis of jumbled spine and ribs (Jsr) mutation affecting the vertebral development in mice

The jumbled spine and ribs (Jsr) mouse was derived from a spontaneous mutation. As the phenotype, a shortened trunk and kinky tail are characteristic Jsr traits. In this study, on high resolution mapping it was found that Lunatic fringe (Lfng) mapped at the same position as Jsr. Lfng was identified as the candidate gene for Jsr, but sequence analysis of this gene revealed no substitution in the coding region of cDNA. Therefore, we adopted the strategy of positional cloning for Jsr using a mouse bacterial artificial chromosome (BAC) library. A BAC contig was constructed from three BAC clones showing positive signals of Lfng and 11MMHAP75FRD8.seq near the Jsr locus on chromosome 5. Based on the genetic mapping of both T7 and sp6 ends of a clone of BAC382-O-7 (BAC382), the Jsr gene was considered to exist in BAC382 and to be positioned near the sp6 side.     

Steel (Sl) mutation in mice: Identification of mutant embryos early in development

A method is described for the reliable identification of Steel mutant mouse embryos in segregating litters as early as Day 11 of gestation based on the color of hair developed in embryonic skin explants.     

Role of poly(ADP-ribose) glycohydrolase in the development of inflammatory bowel disease in mice

Poly(ADP-ribose) is synthesized from nicotinamide adenine dinucleotide (NAD) by poly(ADP-ribose) polymerase 1 (PARP-1) and degraded by poly(ADP-ribose) glycohydrolase (PARG). The aim of the present study was to examine the role of PARG in the development of experimental colitis. To address this question, we used an experimental model of colitis, induced by dinitrobenzene sulfonic acid (DNBS). Mice lacking the functional 110-kDa isoform of PARG (PARG(110)KO mice) were resistant to colon injury induced by DNBS. The mucosa of colon tissues showed reduction of myeloperoxidase activity and attenuated staining for intercellular adhesion molecule 1 and vascular cell adhesion molecule 1. Moreover, overproduction of proinflammatory factors TNF-alpha and IL-1beta and activation of cell death signaling pathway, i.e., the FAS ligand, were inhibited in these mutant mice. Finally pharmacological treatment of WT mice with GPI 16552 and 18214, two novel PARG inhibitors, showed a significant protective effect in DNBS-induced colitis. These genetic and pharmacological studies demonstrate that PARG modulates the inflammatory response and tissue injury events associated with colitis and PARG may be considered as a novel target for pharmacological intervention for the pathogenesis.     

Role of missense mutation (M235T) in the angiotensinogen gene in development of cerebral ischemia

Possible correlation of M/T polymorphism of angiotensinogen gene with risk of ischemic stroke and basic risk factors of cerebral pathology (levels of arterial pressure and blood cholesterol; presence of diabetes mellitus, coronary heart disease, or myocardial infarction in anamnesis; and stenosis of major cerebral arteries) was studied. It was shown that M/T polymorphic variants of angiotensinogen gene were factors determining neither clinical variant of cerebral ischemia development (acute ischemic stroke or chronic brain ischemia) nor formation of main risk factors of stroke.     

Effects of dietary lactosucrose (4G-beta-D-galactosylsucrose) on the IgE response in mice

In this study, we examined the effects of dietary lactosucrose (LS, a non-digestible oligosaccharide) on the IgE response in mice immunized with ovalbumin (OVA)/alum. In addition to IgG1 and IgG2a responses, the anti-OVA IgE response in mice fed LS diets was dose-dependently suppressed, as compared with the control mice, while the serum total IgG levels were comparable. Moreover, dietary LS feeding inhibited antigen-specific IgE and IgG1 productions even after a second immunization. Regarding with cytokine production, when stimulated in vitro with OVA, splenocytes obtained from LS-fed mice produced a similar level of IFN-gamma, and lower levels of IL-4 and IL-5, as compared with the control mice. But IL-10 production by OVA-stimulated splenocytes was augmented in LS-fed mice, suggesting that IL-10 producing cells are responsible for the immunoregulatory effect of LS. Our findings indicate the further possibility that dietary LS supplementation can be used to prevent IgE-mediated allergic diseases.     

The role of immunity on the development of dermatitis in NC mice

In order to clarify the role of immunity on the development of dermatitis in NC mice, the following experiments were carried out. In neonatal thymectomized NC, thymic reconstituted NC-nu/nu, and passively serum transferred NC-nu/nu mice, incidence of the dermatitis was examined. Immune response to sheep red blood cells (SRBC) and number of Thy-1 positive cells in mesenteric lymph node were used as indicators of the cell mediated immunity. Although antibody to SRBC and the number of Thy-1 positive cells in neonatal thymectomized NC mice were greatly reduced, development of the dermatitis in these mice was not suppressed at all. On the contrary, thymic reconstituted NC-nu/nu mice which recovered immune response to SRBC and number of Thy-1 positive cells to the normal levels did not develop the dermatitis. Passive transfer of the serum obtained from NC mice which developed severe dermatitis, could not induce the dermatitis in NC-nu/nu mice. These results suggest that the dermatitis in NC mice is not mediated by immune mechanisms but by other complexed factors. The absence of the dermatitis in NC-nu/nu mice may be due to nu gene effects other than those of immune defect.     

Hyper IgE in New Zealand black mice due to a dominant-negative CD23 mutation

Immunoglobulin E (IgE) plays a critical role in both resistance to parasitic infection and allergy to environmental antigens. The IgE response is in turn regulated by the B-cell co-receptor CD23, and CD23-deficient mice show exaggerated IgE responses and airway hyper-responsiveness. In this report, we show that New Zealand black (NZB) mice express a variant CD23 allele, with mutations in both the C-lectin-binding domain and stalk region, which fails to bind IgE at high affinity and has reduced expression on the cell surface. Expression of the variant CD23 chain interferes with trimerisation of the receptor and has a dominant-negative effect leading to reduced IgE binding in crosses between NZB and other strains. Genetic mapping shows that the variant CD23 leads to an exaggerated primary IgE response, which is independent of other strain-specific effects. These results suggest that NZB mice or mice carrying the variant allele will be useful models for studying both allergy and quantitative traits associated with atopy. The exaggerated IgE response provides an explanation for the natural resistance of NZB mice to parasitic infection by Leishmania.     

Role of specific IgE antibodies in peroxidase (EPO) release from human eosinophils

After the demonstration of cytophilic IgE immunoglobulins (Ig) on human blood and lung eosinophils, their role in cell activation was studied by eosinophil peroxidase (EPO) assay. Hypodense human eosinophils from filariasis-infected patients were activated by anti-human Ig or various antigens. A selective release of EPO occurred after incubation with anti-human IgE, but not with anti-human IgG. The activation by antigens showed a strict antibody specificity of cytophilic IgE antibodies. The direct involvement of IgE antibodies in activation by the specific antigen was evidenced by inhibition experiments with aggregated human IgE myeloma protein. Circulating IgE antibodies exhibiting the same specificity and able to induce EPO release were detected in the sera from filariasis patients by a passive sensitization assay. Only the hypodense eosinophils were able to release EPO after IgE-dependent activation both in the direct assay and in the passive sensitization test, confirming the functional heterogeneity of human eosinophils. These results suggest that the interaction between IgE antibodies and human eosinophils can play a role both in protective immunity and pathology by releasing active pharmacologic mediators.     

Suppression of IgE antibody production in SJL mice. V. Effect of irradiation and adult thymectomy on the suppression of IgE antibody production in SJL mice

Anti-DNP IgE antibody production was low and transient in SJL mice which were immunized with 1 microgram DNP-Nb and 1 mg A1(OH)3. The immunized SJL mice were irradiated (60-540 R) 1 day after challenge. A dose higher than 180 R induced enhancement of anti-DNP IgE antibody production as compared to nonirradiated control mice, suggesting the existence of irradiation-sensitive suppressor cells. Anti-DNP IgE antibody production was suppressed when immunized and irradiated SJL mice were injected with spleen cells from adult-thymectomized SJL mice. The donors of the spleen cells were thymectomized 2 or 4 months previously, and this suggests that the suppressor cells from unprimed mice are long-living T cells.     

Dietary pulverized konjac glucomannan prevents the development of allergic rhinitis-like symptoms and IgE response in mice

Konjac is a traditional Japanese food with a peculiar texture, and it has been suggested that its main ingredient, konjac glucomannan (KGM), ameliorates metabolic disorders such as diabetes and hypercholesteremia. We have found that feeding with pulverized KGM (PKGM) prevents skin inflammation in a murine model of atopic dermatitis. Here, we show that dietary PKGM suppresses allergic rhinitis-like symptoms in mice upon immunization and nasal sensitization with ovalbumin (OVA). The PKGM-fed mice showed a much lower frequency of sneezing than in control animals. We also found that PKGM supplementation exclusively suppressed OVA-specific IgE response without affecting IgG1/IgG2a responses as well as systemic Th1/Th2 cytokine production. These results suggest that PKGM can be a beneficial foodstuff in preventing nasal allergy such as seasonal pollinosis.     

Steel-Dickie (Sld) mutation affects both maintenance and differentiation of testicular germ cells in mice.

The effects of Steel-Dickie (Sld) mutations on testicular germ cell differentiation were investigated using experimental cryptorchidism and its surgical reversal in mutant, C57BL/6-Sld/+ and wild-type C57BL/6- +/+ mice. In Sld/+ cryptorchid testes the maintenance of undifferentiated type-A spermatogonia was impaired and their numbers decreased. In contrast, the proliferative activity of type-A spermatogonia in the cryptorchid testis of mutant mice appeared normal as judged by their progression through the cell cycle. Surgical reversal of cryptorchidism resulted in regenerative differentiation of mature germ cells in +/+ testes. However, the regenerative differentiation of type-A spermatogonia which remained in Sld/+ cryptorchid testes was strongly impaired, particularly at two steps of cellular differentiation, from type-A spermatogonia to intermediate or type-B spermatogonia and at meiotic division. Furthermore, in mutant mice, no significant recovery of testicular weight was observed after surgical reversal compared with +/+ mice.     

Role of pathogenicity factors of Staphylococcus aureus in development of atopic dermatitis

Factors of pathogenicity of staphylocci and their key role in pathologic process are discussed. Staphylococcus aureus is the leading etiological agent infecting skin of the patients with atopic dermatitis. Development of atopic eczema in patients infected by Staphylococcus aureus is in much determined by wide spectrum of virulence factors inherent to this type of staphylococci. Among those, the more important are proteinases, destroying antimicrobial peptides of derma, toxins, superantigens, which can cause and support of inflammatory reaction in derma during this disease. It was specially noted that pathogenicity factors should be studied as complex system, which formed as a result of long joint evolution of opportunistic microflora and immune system of the host.     

Role of adrenal glands in the development of abnormal glucose and insulin homeostasis in genetically obese (ob/ob) mice

This study evaluates the role of adrenal hormones in the development of hyperinsulinaemia and impaired glucose homeostasis in genetically obese hyperglycaemic C57BL/6J ob/ob mice. Lean (+/?) and obese mice were bilaterally adrenalectomised or sham operated at 5 weeks of age, and glucose tolerance was examined after 7 and 14 days. Adrenalectomy temporarily reduced food intake and body weight gain in lean mice, and improved glucose tolerance without a significant change in plasma insulin concentrations at both intervals studied. In obese mice adrenalectomy permanently reduced body weight gain and food intake to values comparable with lean mice. Glucose tolerance was improved in adrenalectomised obese mice at both intervals studied, resulting in plasma glucose concentrations similar to adrenalectomised lean mice. Plasma insulin concentrations during the tolerance tests were reduced in adrenalectomised obese mice, but remained higher than in lean mice. Adrenalectomy did not improve the poor insulin response to parenteral glucose in obese mice. The results indicate that adrenal hormones play an important role in the development of glucose intolerance and contribute to the hyperinsulinaemia in obese (ob/ob) mice, in part by promoting hyperphagia.     

Control of IgE and IgG1 antibody production in mice.

The production of IgE and IgG1 was studied in untreated, thymectomized. splenectomized, anti-thymocyte serum-treated, or sublethally X-irradiated mice. Dinitrophenyl Ascaris and ovalbumin were used as antigens, and aluminum hydroxide was used as adjuvant. A suppression of IgE production was observed in adult thymectomized mice, although the kinetic pattern of the antibody response was the same as in control animals. IgG1 antibody production was not affected by thymectomy. Splenectomy did not change either IgE or IgG1 production. A single dose of rabbit anti-thymocyte serum (ATS) given 8 days after immunization inhibited IgE antibody production. The effect of ATS was dose dependent and also varied with the amount of antigen used, the immune response to high doses being more susceptible to the effect of ATS. No alteration in IgG1 production was caused by ATS even when IgE antibody formation was completely inhibited. When preceding immunization, sublethal irradiation enhanced IgE antibody formation and partially suppressed IgG1 production; applied after immunization, irradiation caused an enhancement of IgE production which was inversely proportional to the interval elapsed between the two procedures. On the other hand, the IgG1 antibody production was fairly resistant to the same treatment. The results suggest a clearcut separation between the mechanisms regulating IgE and IgG1 production in mice.     

Role of endogenous retroviruses as mutagens: the hairless mutation of mice

We have developed an experimental approach to distinguish the 40-60 endogenous C-type proviruses of mice and to determine their association with well characterized developmental and physiological mutations. The hairless (hr) mutation causes a variety of pleiotropic effects. Using oligonucleotide probes specific for different classes of murine leukemia virus, we have identified and cloned a provirus present in HRS/J hr/hr animals but absent in HRS/J +/+. Genetic analyses showed perfect concordance between the hr phenotype and the presence of the provirus in a number of inbred and congenic strains of mice. Molecular analysis of a haired revertant established the causal relationship since it revealed the excision of most of the proviral genome leaving behind one long terminal repeat. These findings show that virus integration caused the hairless mutation and point to the utility of naturally occurring retroviral integrations for accessing the genome of the mouse.