Lung- and liver-dominant phenotypes of Korean eight constitution medicine have different profiles of genotype associated with each organ function.

Eight Constitution Medicine (ECM), a ramification of traditional Korean medicine, has categorized people into eight constitutions. The main criteria of classification are inherited differences or predominance in the functions of organs, such as the liver or lung, diagnosed through ECM-specific pulse patterns. This study investigated the association between single nucleotide polymorphism (SNP) genotypes and ECM phenotypes and explored candidate genetic makeups responsible for each constitution using a genome-wide association study (GWAS). Sixty-three healthy volunteers, who were either categorized as the Hepatonia (HEP, n = 32) or Pulmotonia (PUL, n = 31) constitution, were enrolled. HEP and PUL are two contrasting ECM types representing the dominant liver and lung phenotypes, respectively. SNPs were analyzed from the oral mucosa DNA using a commercially available microarray chip that can identify 820,000 SNPs. We conducted GWAS using logistic regression analysis and additive mode genotypes and constructed phylogenetic trees using the SNPhylo program with 8 SNPs specific for the liver phenotype and 15 SNPs for the lung phenotype. Although genome-wide significant SNPs were not found, the phylogenetic tree showed a clear difference between the two constitutions. This is the first observation suggesting genetic involvement in the ECM and can be extended to all ECM constitutions.

The Drosophila Perlecan gene trol regulates multiple signaling pathways in different developmental contexts.

BACKGROUND: Heparan sulfate proteoglycans modulate signaling by a variety of growth factors. The mammalian proteoglycan Perlecan binds and regulates signaling by Sonic Hedgehog, Fibroblast Growth Factors (FGFs), Vascular Endothelial Growth Factor (VEGF) and Platelet Derived Growth Factor (PDGF), among others, in contexts ranging from angiogenesis and cardiovascular development to cancer progression. The Drosophila Perlecan homolog trol has been shown to regulate the activity of Hedgehog and Branchless (an FGF homolog) to control the onset of stem cell proliferation in the developing brain during first instar. Here we extend analysis of trol mutant phenotypes to show that trol is required for a variety of developmental events and modulates signaling by multiple growth factors in different situations. RESULTS: Different mutations in trol allow developmental progression to varying extents, suggesting that trol is involved in multiple cell-fate and patterning decisions. Analysis of the initiation of neuroblast proliferation at second instar demonstrated that trol regulates this event by modulating signaling by Hedgehog and Branchless, as it does during first instar. Trol protein is distributed over the surface of the larval brain, near the regulated neuroblasts that reside on the cortical surface. Mutations in trol also decrease the number of circulating plasmatocytes. This is likely to be due to decreased expression of pointed, the response gene for VEGF/PDGF signaling that is required for plasmatocyte proliferation. Trol is found on plasmatocytes, where it could regulate VEGF/PDGF signaling. Finally, we show that in second instar brains but not third instar brain lobes and eye discs, mutations in trol affect signaling by Decapentaplegic (a Transforming Growth Factor family member), Wingless (a Wnt growth factor) and Hedgehog. CONCLUSION: These studies extend the known functions of the Drosophila Perlecan homolog trol in both developmental and signaling contexts. These studies also highlight the fact that Trol function is not dedicated to a single molecular mechanism, but is capable of regulating different growth factor pathways depending on the cell-type and event underway.

DNA repair defects in stem cell function and aging.

Cellular DNA is under constant challenge by exogenous and endogenous genotoxic stress, which results in both transient and accumulated DNA damage and genomic instability. All cells are equipped with DNA damage response pathways that trigger DNA repair, cell cycle arrest, and, if need be, apoptosis, to eliminate DNA damage or damaged cells. The consequences of these processes for stem cells can be profound: diminution in stem cell pools, or, because of altered gene expression, an increased chance for stem cell differentiation or malignant transformation. Furthermore, a number of DNA repair abnormalities are linked to premature aging syndromes, and these are associated with defects in the stem cell population. The specific DNA repair systems for which there are data regarding the impact of repair defects on stem cell function include O(6)-alkylguanine DNA alkyltransferase, nucleotide excision repair, base excision repair, mismatch repair, non-homologous DNA end-joining Fanconi's anemia protein complex, and homologous recombination. It has recently become clear that deficiencies of these processes are associated not only with cancer and/or aging but also with stem cell defects. This discovery raises the possibility of a link between aging and stem cell dysfunction. In this review, we provide evidence for a link between DNA repair systems and the maintenance and longevity of stem cells.

Induction of string rescues the neuroblast proliferation defect in trol mutant animals.

In trol mutants, neuroblasts fail to exit G1 for S phase. Increasing string expression in trol mutants rescues the number of S phase neuroblasts without an increase in M phase neuroblasts. Decreasing string expression further decreased the number of S phase neuroblasts. Coexpression of cyclin E and string did not produce additional S phase cells. Unlike cyclin E, cdk2, and cdk2AF, elevated expression of neither cyclin A, cyclin D, nor cdk1AF was able to promote S phase progression in arrested neuroblasts, indicating that String-induced activity of a Cyclin A or Cyclin D complex is unlikely to drive trol neuroblasts into S phase. Biochemical analyses revealed a rapid increase of Cyclin E-Cdk2 kinase activity to wild-type levels upon increased string expression. These results suggest that Drosophila Cdc25 may directly or indirectly increase the kinase activity of Cyclin E-Cdk2 complexes in vivo, thus driving arrested neuroblasts into cell division.

Drosophila perlecan modulates FGF and hedgehog signals to activate neural stem cell division.

Mutations in the Drosophila trol gene cause cell cycle arrest of neuroblasts in the larval brain. Here, we show that trol encodes the Drosophila homolog of Perlecan and regulates neuroblast division by modulating both FGF and Hh signaling. Addition of human FGF-2 to trol mutant brains in culture rescues the trol proliferation phenotype, while addition of a MAPK inhibitor causes cell cycle arrest of the regulated neuroblasts in wildtype brains. Like FGF, Hh activates stem cell division in the larval brain in a Trol-dependent fashion. Coimmunoprecipitation studies are consistent with interactions between Trol and Hh and between mammalian Perlecan and Shh that are not competed with heparin sulfate. Finally, analyses of mutations in trol, hh, and ttv suggest that Trol affects Hh movement. These results indicate that Trol can mediate signaling through both of the FGF and Hedgehog pathways to control the onset of stem cell proliferation in the developing nervous system.