Yoshito Ueyama

To establish a more appropriate animal recipient for xenotransplantation, NOD/SCID/gamma(c)(null) mice double homozygous for the severe combined immunodeficiency (SCID) mutation and interleukin-2Rgamma (IL-2Rgamma) allelic mutation (gamma(c)(null)) were generated by 8 backcross matings of C57BL/6J-gamma(c)(null) mice and NOD/Shi-scid mice. When human CD34+ cells from umbilical cord blood were transplanted into this strain, the engraftment rate in the peripheral circulation, spleen, and bone marrow were significantly higher than that in NOD/Shi-scid mice treated with anti-asialo GM1 antibody or in the beta2-microglobulin-deficient NOD/LtSz-scid (NOD/SCID/beta2m(null)) mice, which were as completely defective in NK cell activity as NOD/SCID/gamma(c)(null) mice. The same high engraftment rate of human mature cells was observed in ascites when peripheral blood mononuclear cells were intraperitoneally transferred. In addition to the high engraftment rate, multilineage cell differentiation was also observed. Further, even 1 x 10(2) CD34+ cells could grow and differentiate in this strain. These results suggest that NOD/SCID/gamma(c)(null) mice were superior animal recipients for xenotransplantation and were especially valuable for human stem cell assay. To elucidate the mechanisms involved in the superior engraftment rate in NOD/SCID/gamma(c)(null) mice, cytokine production of spleen cells stimulated with Listeria monocytogenes antigens was compared among these 3 strains of mice. The interferon-gamma production from dendritic cells from the NOD/SCID/gamma(c)(null) mouse spleen was significantly suppressed in comparison with findings in 2 other strains of mice. It is suggested that multiple immunological dysfunctions, including cytokine production capability, in addition to functional incompetence of T, B, and NK cells, may lead to the high engraftment levels of xenograft in NOD/SCID/gamma(c)(null) mice.

The adipocyte-derived hormone adiponectin has been shown to play important roles in the regulation of energy homeostasis and insulin sensitivity. In this study, we analyzed globular domain adiponectin (gAd) transgenic (Tg) mice crossed with leptin-deficient ob/ob or apoE-deficient mice. Interestingly, despite an unexpected similar body weight, gAd Tg ob/ob mice showed amelioration of insulin resistance and beta-cell degranulation as well as diabetes, indicating that globular adiponectin and leptin appeared to have both distinct and overlapping functions. Amelioration of diabetes and insulin resistance was associated with increased expression of molecules involved in fatty acid oxidation such as acyl-CoA oxidase, and molecules involved in energy dissipation such as uncoupling proteins 2 and 3 and increased fatty acid oxidation in skeletal muscle of gAd Tg ob/ob mice. Moreover, despite similar plasma glucose and lipid levels on an apoE-deficient background, gAd Tg apoE-deficient mice showed amelioration of atherosclerosis, which was associated with decreased expression of class A scavenger receptor and tumor necrosis factor alpha. This is the first demonstration that globular adiponectin can protect against atherosclerosis in vivo. In conclusion, replenishment of globular adiponectin may provide a novel treatment modality for both type 2 diabetes and atherosclerosis.

By using Southern blot analysis, we found that in two cases of human glioblastoma multiforme, cells carried amplified c-erbB genes which bore short deletion mutations within the ligand-binding domain of the epidermal growth factor (EGF) receptor. The products of these mutated c-erbB genes were about 30 kilodalton (kDa) smaller than the normal 170-kDa EGF receptor, and the tumor cell membrane fractions containing the 140-kDa abnormal EGF receptor showed a significant elevation of tyrosine kinase activity without its ligand. In view of the similarity to the activated viral and cellular erbB genes in the avian system, these mutated and overexpressed EGF receptors might play a role in the onset or development of human glioblastoma cells.