Cardiac failure has a principal underlying aetiology of ischaemic damage arising from vascular insufficiency. Molecules that regulate collateral growth in the ischaemic heart also regulate coronary vasculature formation during embryogenesis. Here we identify thymosin beta4 (Tbeta4) as essential for all aspects of coronary vessel development in mice, and demonstrate that Tbeta4 stimulates significant outgrowth from quiescent adult epicardial explants, restoring pluripotency and triggering differentiation of fibroblasts, smooth muscle cells and endothelial cells. Tbeta4 knockdown in the heart is accompanied by significant reduction in the pro-angiogenic cleavage product N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP). Although injection of AcSDKP was unable to rescue Tbeta4 mutant hearts, it significantly enhanced endothelial cell differentiation from adult epicardially derived precursor cells. This study identifies Tbeta4 and AcSDKP as potent stimulators of coronary vasculogenesis and angiogenesis, and reveals Tbeta4-induced adult epicardial cells as a viable source of vascular progenitors for continued renewal of regressed vessels at low basal level or sustained neovascularization following cardiac injury.

Nkx2-5, one of the earliest cardiac-specific markers in vertebrate embryos, was used as a genetic locus to knock in the Cre recombinase gene by homologous recombination. Offspring resulting from heterozygous Nkx2-5/Cre mice mated to ROSA26 (R26R) reporter mice provided a model system for following Nkx2-5 gene activity by beta-galactosidase (beta-gal) activity. beta-gal activity was initially observed in the early cardiac crescent, cardiomyocytes of the looping heart tube, and in the epithelium of the first pharyngeal arch. In later stage embryos (10.5-13.5 days postcoitum, dpc), beta-gal activity was observed in the stomach and spleen, the dorsum of the tongue, and in the condensing primordium of the tooth. The Nkx2-5/Cre mouse model should provide a useful genetic resource to elucidate the role of loxP manipulated genetic targets in cardiogenesis and other developmental processes.

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Prostate Cancer Early Detection provide recommendations for prostate cancer screening in healthy men who have elected to participate in an early detection program. The NCCN Guidelines focus on minimizing unnecessary procedures and limiting the detection of indolent disease. These NCCN Guidelines Insights summarize the NCCN Prostate Cancer Early Detection Panel's most significant discussions for the 2016 guideline update, which included issues surrounding screening in high-risk populations (ie, African Americans, BRCA1/2 mutation carriers), approaches to refine patient selection for initial and repeat biopsies, and approaches to improve biopsy specificity.

Mutations in developmental regulatory genes have been found to be responsible for some cases of congenital heart defects. One such regulatory gene is Gata4, a zinc finger transcription factor. In order to circumvent the early embryonic lethality of Gata4-null embryos and to investigate the role of myocardial Gata4 expression in cardiac development, we used Cre/loxP technology to conditionally delete Gata4 in the myocardium of mice at an early and a late time point in cardiac morphogenesis. Early deletion of Gata4 by Nkx2-5Cre resulted in hearts with striking myocardial thinning, absence of mesenchymal cells within the endocardial cushions, and selective hypoplasia of the RV. RV hypoplasia was associated with downregulation of Hand2, a transcription factor previously shown to regulate formation of the RV. Cardiomyocyte proliferation was reduced, with a greater degree of reduction in the RV than in the LV. Late deletion of Gata4 by Cre recombinase driven by the alpha myosin heavy chain promoter did not selectively affect RV development or generation of endocardial cushion mesenchyme but did result in marked myocardial thinning with decreased cardiomyocyte proliferation, as well as double-outlet RV. Our results demonstrate a general role of myocardial Gata4 in regulating cardiomyocyte proliferation and a specific, stage-dependent role in regulating the morphogenesis of the RV and the atrioventricular canal.

The Bmp4 signaling molecule is expressed in ventral splanchnic and branchial-arch mesoderm and outflow-tract (OFT) myocardium, suggesting a role for Bmp4 in OFT development. Inactivation of Bmp4 in the caudal branchial arch and splanchnic mesoderm and OFT myocardium by using a conditional null allele of Bmp4 and the Nkx2.5 cre recombinase allele resulted in abnormal morphogenesis of branchialarch arteries (BAAs) and defective OFT septation. Expression of aortic-sac myocardial markers was reduced and expression of the sm22 LacZ transgene, a smooth-muscle marker, was attenuated in BAAs and conotruncus of Nkx2.5 cre ; Bmp4 conditional mutants. Moreover, we found tissue-specific functions for Bmp4 in the regulation of cellular proliferation and apoptosis. We also demonstrate a strong genetic interaction between Bmp4 and Bmp7 in OFT development. Our findings uncover a previously uncharacterized function for Bmp4 in vascular remodeling of the BAAs, and they show definitively that Bmp4, in cooperation with Bmp7, has a central role in OFT septation. T he vertebrate heart can be subdivided into inflow, outflow, and primitive-ventricular regions (1). The cardiac outflow tract (OFT), which develops from the anterior part of the linear heart tube, forms the right-sided conotruncal region after heart looping. Initially unseptated, the OFT divides into the pulmonary trunk (PT) and aorta, and it is critical for separation of postnatal pulmonary and systemic circulation. Congenital OFT malformations are common, making an understanding of the genetic pathways regulating OFT development an important goal in developmental biology and clinical medicine.At defined areas of the OFT, endocardial cells undergo an epithelial to mesenchymal transformation (perhaps in response to a signal from overlying myocardium) and invade the intervening space to form the endocardial cushions. The cardiac neural crest also invades the forming aorto-pulmonary (AP) septum and OFT cushions (2). The OFT myocardium receives an additional input from splanchnic and branchial-arch mesoderm, the anterior or secondary heart field (SHF), which may be important for OFT lengthening and morphogenesis (3).Bmp4 is a member of the Bone morphogenetic protein (Bmp) subclass of transforming growth factor type ␤ (TGF-␤)-signaling molecules (4). Bmp4 expression in splanchnic and branchial-arch mesoderm (which contributes to OFT myocardium) and within the OFT myocardium itself suggests a role in OFT morphogenesis (ref.5 and see below). Investigation of Bmp4 function in cardiac development has been hampered by the early embryonic lethality of Bmp4 null mutant embryos (6). Recent work analyzing an allele of the ubiquitously expressed Bmp type 2 receptor (Bmpr2), containing a partial ectodomain deletion, revealed defective proximal OFT septation in mouse embryos, providing insight into Bmp function in the OFT (7). However, because Bmpr2 is broadly expressed, the developmental mechanisms responsible for the cushion defects remain unclear. Overexpression of noggin in chick embry...

The genetic control of cell fate specification, morphogenesis and expansion of the spleen, a crucial lymphoid organ, is poorly understood. Recent studies of mutant mice implicate various transcription factors in spleen development,but the hierarchical relationships between these factors have not been explored. In this report, we establish a genetic network that regulates spleen ontogeny, by analyzing asplenic mice mutant for the transcription factors Pbx1, Hox11 (Tlx1), Nkx3.2 (Bapx1) and Pod1 (capsulin, Tcf21). We show that Hox11 and Nkx2.5, among the earliest known markers for splenic progenitor cells, are absent in the splenic anlage of Pbx1homozygous mutant (-/-) embryos, implicating the TALE homeoprotein Pbx1 in splenic cell specification. Pbx1 and Hox11genetically interact in spleen formation and loss of either is associated with a similar reduction of progenitor cell proliferation and failed expansion of the splenic anlage. Chromatin immunoprecipitation assays show that Pbx1 binds to the Hox11 promoter in spleen mesenchymal cells, which co-express Pbx1 and Hox11. Furthermore, Hox11 binds its own promoter in vivo and acts synergistically with TALE proteins to activate transcription,supporting its role in an auto-regulatory circuit. These studies establish a Pbx1-Hox11-dependent genetic and transcriptional pathway in spleen ontogeny. Additionally, we demonstrate that while Nkx3.2 and Pod1 control spleen development via separate pathways, Pbx1genetically regulates key players in both pathways, and thus emerges as a central hierarchical co-regulator in spleen genesis.

COUP-TFII, an orphan member of the steroid receptor superfamily,has been implicated in mesenchymal-epithelial interaction during organogenesis. The generation of a lacZ knock-in allele in the COUP-TFII locus in mice allows us to use X-gal staining to follow the expression of COUP-TFII in the developing stomach. We found COUP-TFII is expressed in the mesenchyme and the epithelium of the developing stomach. Conditional ablation of floxed COUP-TFII by Nkx3-2Cre recombinase in the gastric mesenchyme results in dysmorphogenesis of the developing stomach manifested by major patterning defects in posteriorization and radial patterning. The epithelial outgrowth,the expansion of the circular smooth muscle layer and enteric neurons as well as the posteriorization of the stomach resemble phenotypes exhibited by inhibition of hedgehog signaling pathways. Using organ cultures and cyclopamine treatment, we showed downregulation of COUP-TFII level in the stomach, suggesting COUP-TFII as a target of hedgehog signaling in the stomach. Our results are consistent with a functional link between hedgehog proteins and COUP-TFII, factors that are vital for epithelial-mesenchymal interactions.

A B S T R A C T PurposeMen diagnosed with prostate cancer have multiple options available for treatment. Previous reports have indicated a trend of differing modalities of treatment chosen by African American and white men. We investigated the role of ethnicity in primary treatment choice and how this affected overall and cancer-specific mortality. MethodsBy utilizing data abstracted from Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE), patients were compared by ethnicity, primary treatment, number of comorbidities, risk level according to modified D'Amico criteria, age, highest educational level attained, type of insurance, treatment facility, and perception of general health. Multinomial logistic regression analysis was performed to determine the effect of the tested variables on primary treatment and mortality. ResultsAfrican American men were more likely to receive nonsurgical therapy than white men with equivalent disease characteristics. Whites were 48% less likely than African Americans to receive androgen deprivation therapy (ADT) compared with surgery (P ϭ .02) and were 25% less likely than African Americans to receive radiation therapy compared with surgery (P ϭ .08). Whites with low-risk disease were 71% less likely to receive ADT than African American men with similar disease (P ϭ .01). Adjusted overall and prostate cancer-specific mortality were not significantly different between whites and African Americans (hazard ratios, 0.73 and 0.37, respectively). Risk level, type of treatment, and type of insurance had the strongest effects on risk of mortality. ConclusionThere is a statistically significant difference in primary treatment for prostate cancer between African American and white men with similar risk profiles. Additional research on the influence of patient/physician education and perception and the role that socioeconomic factors play in mortality from prostate cancer may be areas of focus for public health initiatives.