Scanning electron microscopy (SEM) observation showed that fully differentiated spherical adipocytes were embraced by a network of collagens and fibroblastic preadipocytes. The properties of both the collagen networks and the preadipocytes allow the adipocytes to be interconnected, forming a fat-cell cluster, which can anchor to the bottom of a culture dish. In this network structure, collagen fibrils and fibrillar bundles were closely arranged and stratified. We found that immunostained collagens appeared to form extracellular network structures, which can be observed by SEM. The extracellular network of fibronectin was the first to develop among the extracellular matrix (ECM) components, though it became degraded with the progress of adipocyte differentiation. The type I collagen network was the last to develop and remained well organized through the late stage of adipocyte differentiation. The extracellular networks of type III, V, and VI collagen developed by the mid-stage and remained in the late stage of adipocyte differentiation. The network structures of type IV collagen and laminin became degraded during the differentiation process and localized at the surface of spherical cells. In addition to these basement membrane components, types III, V, and VI collagens also showed pericellular spherical staining patterns. These results demonstrated that the constitution and distribution of the ECM are altered during adipocyte differentiation, suggesting that the organization of each ECM component into a suitable structure is a requirement for the differentiation and maintenance of unilocular adipocytes.

Abstract. Dolly, the first mammal cloned from a somatic cell, had shorter telomeres than age-matched controls and died at an early age because of disease. To investigate longevity and lifetime performance in cloned animals, we produced cloned cows with short telomeres using oviductal epithelial cells as donor cells. At 5 years of age, despite the presence of short telomeres, all cloned cows delivered multiple healthy offspring following artificial insemination with conventionally processed spermatozoa from noncloned bulls, and their milk production was comparable to that of donor cows. Moreover, this study revealed that the offspring had normal-length telomeres in their leukocytes and major organs. Thus, cloned animals have normal functional germ lines, and therefore germ line function can completely restore telomere lengths in clone gametes by telomerase activity, resulting in healthy offspring with normal-length telomeres. Key words: Aging, Cattle, Mammalian cloning, Germ line, Telomere (J. Reprod. Dev. 57: [636][637][638][639][640][641][642] 2011) n mammals, most somatic cells undergo a finite number of cell divisions and ultimately enter a nondividing state known as replicative senescence [1] as a consequence of structural changes that take place in chromosomes over time. Chromosomes terminate in a nucleoprotein complex termed a telomere, which consists of repetitive sequences of G-rich noncoding DNA (TTAGGG)n and specific proteins. Telomeres are attached to the nuclear matrix and protect chromosome ends from degradation, fusion and recombination [2]. However, conventional DNA polymerases cannot replicate the extreme 5' ends of chromosomes because removal of the most terminal RNA primer in the lagging strand leaves a small region of uncopied DNA; therefore, telomeres are incrementally eroded with each cell division [3]. On the basis of this mechanism, it has been proposed that progressive telomere shortening during each cell division eventually yields a threshold telomere length beyond which additional normal cell divisions are not possible. Thus, telomere length acts as a mitotic clock that accounts for the limited lifespan of cells [4].In recent years, animal production by somatic cell nucleus transfer (SCNT) has offered a range of opportunities in basic and applied research, agriculture, genetic conservation and human medicine [5]. Somatic cell-cloned animals are produced using donor cells that have variably aged in vivo and in vitro, raising interesting questions about possible foreshortening effects on the lifespan and reproductive potential of these animals. In some cases, particularly with respect to cows and sheep, there is also the question of potential reductions in overall milk production. In this context, the telomere lengths in Dolly, the first mammal produced by SCNT, have been reported to be significantly shorter than those in age-matched controls, and this was consistent with the age of the donor mammary epithelial cell culture, which was derived from a 6-year-old donor sheep [6]. Dolly di...

To clarify the antiangiogenetic activity of chondromodulin-I (ChM-I), which is a cartilage-specific extracellular matrix (ECM) component, the effect of ChM-I on the four steps of angiogenesis were investigated in vitro. ChM-I markedly inhibited ECM invasion, the first step of angiogenesis, and migration of endothelial cells, the second step of angiogenesis. The proliferation of endothelial cells, the third step, was completely inhibited by ChM-I. Additionally, ChM-I suppressed the cell attachment of endothelial cells and caused the cells to undergo an apoptosis-like morphogenesis. In the final step, imperfect formation of tubelike cellular networks of endothelial cells was caused by ChM-I. ChM-I showed remarkable inhibitory effects on all four steps of angiogenesis in vitro, suggesting that ChM-I is a prominent regulator of the biological condition and that it would be a strong candidate as an antiangiogenic agent for biomedics.