Project description:Pregnancy-associated hypertensive (PAH) mice were maintained by mating females carrying the human angiotensinogen (hAGT) gene with males expressing the human renin (hRN) gene, as previously described (Takimoto E., et al., Science, 1996). Angiotensin II (AngII) has critical roles in regulation of blood pressure. In late pregnancy of PAH mice, increased AngII causes acute and severe hypertension with proteinuria. Furthermore, PAH mice show cardiac hypertrophy, fibrosis and apoptosis. It is known that AngII downregulates mRNA of alpha 1a-adrenergic receptor (Adra1a) in neonatal rat cardiac myocytes (Li H.T., et al., Circ. Res., 1997). Interestingly, we found that Adra1a knock out PAH (PAH/aKO) mice display more severe phenotype of cardiac hypertrophy in comparison to PAH mice. In this study, to understand the molecular basis of cardiac hypertrophy via regulation of Adra1a expression with AngII in PAH mice, we performed a comprehensive analysis of gene expression changes in cardiac remodeling of PAH and PAH/aKO mice using the next-generation RNA sequencing (RNA-seq).
Project description:As an essential micronutrient that is scarce in surface ocean waters, zinc (Zn) has the potential to limit oceanic photosynthetic productivity and influence the global carbon cycle. Here we observed Zn co-limitation with iron (Fe) in the natural phytoplankton community of Terra Nova Bay, Antarctica, induced by the drawdown of seawater CO2 and dZn during a bloom. Incubations amended with Zn resulted in significantly higher chlorophyll a content and greater macronutrient and dissolved inorganic carbon drawdown compared to Fe addition alone. Multiple Zn and Fe response proteins were observed in experimental and water column samples demonstrating co-stress in various algal taxa. Together these results demonstrate that Zn limitation can occur in productive Antarctic coastal ecosystems. Thus, Zn may be an important factor limiting the total productivity potential of marine phytoplankton.
Project description:Introduction. Pulmonary arterial hypertension (PAH) is a severe cardiopulmonary disease that may be triggered by exposure to drugs such as dasatinib or facilitated by genetic predispositions. The incidence of dasatinib-associated PAH is estimated at 0.45%, suggesting individual predispositions. The mechanisms of dasatinib-associated PAH are still incomplete. This study studied the link between dasatinib and KCNK3 and the consequences of dasatinib exposure or KCNK3 knockdown in pulmonary endothelial cells (PECs) and pulmonary arterial smooth muscle cells (PASMC). Methods. We discovered a KCNK3 gene variant in a patient with dasatinib-associated PAH and investigated the impact of this variant on KCNK3 function using patch-clamp analysis. Additionally, we assessed the effects of dasatinib exposure on KCNK3 expression and function in human and rat pulmonary arteries. In control-human PASMCs and PECs (hPASMCs and hPECs), we evaluated the consequence of KCNK3 knockdown on cell migration, mitochondrial membrane potential, ATP production, and in vitro tube formation. Using mass spectrometry, we determined the KCNK3 interactome. Results. Patch-clamp revealed that the identified KCNK3 variant represents a loss-of-function variant. Dasatinib contributed to pulmonary artery constriction by decreasing KCNK3 function and expression. In control-hPASMCs, KCNK3 knockdown promotes mitochondrial membrane depolarization and glycolytic shift. Additionally, dasatinib exposure or KCNK3 knockdown reduced the number of caveolae in PECs. Moreover, KCNK3 knockdown in control-hPECs reduced migration, proliferation, and in vitro tubulogenesis. Lastly, using proximity ligation assay and mass spectrometry, we identified the KCNK3 interactome revealing that KCNK3 interaction with various proteins across different cellular compartments could impact these cellular functions. Conclusion. We identified a novel pathogenic variant in the KCNK3 gene, suggesting that KCNK3 gene variations could also influence the development of dasatinib-associated PAH. Our results support that one of the mechanisms of action of dasatinib-associated PAH results from the downregulation of KCNK3.