Biomedical subjects

Seppo Vainio

Publications and source records attributed to Seppo Vainio.

21 records · Page 2Linked to original sources

PubMed2002

Coordinating early kidney development: lessons from gene targeting.

The kidney is widely used to study the mechanisms of organogenesis. Its development involves fundamental processes, such as epithelial branching, induced morphogenesis and cytodifferentiation, which are common to the development of many other organs. Gene-targeting experiments have greatly improved our understanding of kidney development, and have revealed many important genes that regulate early kidney organogenesis, some of which have a role in inherited human kidney disorders. Although our understanding of how the kidney is assembled is still limited, these studies are beginning to provide insights into the genetic and cellular interactions that regulate early organogenesis.

Allantois↗

PubMed2002

Wnt-4 deficiency alters mouse adrenal cortex function, reducing aldosterone production.

Wnt-4 is a signaling factor with multiple roles in organogenesis, a deficiency that leads to abnormal development of the kidney, pituitary gland, female reproductive system, and mammary gland. Wnt-4 is expressed in the cortical region of the developing adrenal gland from embryonic d 11.5 onward, especially in the outermost part. Expression of Cyp11B2 and preadipocyte factor 1 is lowered in the glands of Wnt-4 mutant animals, resulting in significantly reduced aldosterone production in the newborn mutants, suggesting that Wnt-4 may be needed for proper formation of the zona glomerulosa. On the other hand, both proopiomelanocortin-derived peptide beta-endorphin and corticosterone concentration levels are elevated in Wnt-deficient mice, and the expression of Cyp17 is altered in Wnt-4 mutant females, so that it mimics the pattern specific for males. Finally, some cells that are positive for Cyp21, which is normally expressed only in the adrenal gland, are found in the gonads of Wnt-4-deficient embryos, indicating that Wnt-4 may play a role in cell migration or in the sorting of adrenal and gonadal cells during early development. In summary, these results point to a role for Wnt-4 in adrenal gland development and function.

Adrenal Cortex↗

PubMedDate not supplied

The embryonic aorta-gonad-mesonephros region as a generator of haematopoietic stem cells.

During mammalian embryonic development the definitive haematopoietic stem cells (HSCs) may arise either in the extra-embryonic mesoderm or in the aorta-gonad-mesonephros (AGM) region that forms in close proximity to the assembling urogenital system, generating the gonad, cortex of the adrenal gland and metanephros. Researchers have been attempting for a long time to define the region of importance for generating the definitive HSCs that colonize the fetal liver and bone marrow, the two major sites where haematopoiesis takes place in the adult. The fetal liver might gain HSCs from both of the primary haematopoietic sources, but the extra-embryonic HSCs seem not to be able to colonize adult bone marrow directly. It is known that the microenvironment around the HSCs is important for directing cell fates, but we do not yet have much idea about the cell-cell interactions, tissue interactions and molecules that regulate cell behaviour in the AGM. We will here discuss the contribution of the AGM to definitive haematopoiesis in mammals and review some of the cell-cell interactions and associated signalling systems involved in the development of AGM stem cells.

Animals↗