ABSTRACT: Comparison between neonatal and adult heart valve and vascular tissue Tissue engineering of blood vessels and heart valves aims to create high quality prostheses, with preservation of their growth potential. However, the current markers used to identify the necessary cell phenotypes might not take the developmental properties of such structures into account. 4 x 3 replicates
Project description:The goal of this study is to investigate the molecular mechanism of lhx1 on regulation of pronephros formation during the early embryonic development. In the vertebrate embryo the kidney is derived from the intermediate mesoderm. The LIM-class homeobox transcription factor lhx1 is expressed early in the intermediate mesoderm and is one of the first genes to be expressed in the nephric mesenchyme. The animal cap cells can be induced by treatment of activin and retinoic acid to differentiate into pronephros tissue. In this study we investigated the role of Lhx1 in differentiation of pronephros by depleting lhx1 in the organ culture system. We generated the gene expression profile of early pronephros tissue, and demonstrated that expression of genes from all the kidney domains is affected by the absence of lhx1. Taken together our results highlight an essential role for Lhx1 in pronephros formation. lhx1 is involved in driving specification of intermediate mesoderm into nephrogenic mesenchyme. Lhx1 is initially expressed throughout the entire intermediate mesoderm. To determine the role of lhx1 pronephros formation, we performed a microarray analysis using an explant culture system. Xenopus tissue explants can be surgically isolated and cultured under specific conditions to be driven towards many distinct tissue types. Formation of pronephric cell fates is induced by culturing isolated explants in the presence of Activin and RA (AcRA). Treatment of dissected explants of stage 9 blastulae embryos with 10ng/ml Activin and 1x10-4 M retinoic acid can induce differentiation of the pluripotent ectoderm into pan-kidney tissue. For this experiment, both blastomeres of 2-cell embryos were injected with a total of 800pg lhx1 DEED-AS. Explants were dissected and treated with AcRA and expression of pax8 at stage 15 (based on timing of paired control whole embryos) was analyzed. We observed a lack of induction of pax8 expression in lhx1-depleted explants under AcRA treatment conditions in which expression of this gene is normally induced. Based on this observation, microarray analysis was carried out to identify genes whose expression is affected by the absence of lhx1. Explants of injected embryos with 800pg of lhx1 DEED-AS were dissected, treated with pronephric tissue inductive conditions (AcRA) and harvested after 24 hours incubation at 14C (Fig. S5B). The sibling control embryos reached stage 12.5. Explants from uninjected embryos +AcRA and -AcRA as well as explants from DEED injected embryos -AcRA were also harvested. Approximately 12 caps were pooled for each RNA preparation and the analysis was performed using triplicates.
Project description:Fresh frozen sections of islets obtained by surgery were laser capture microdissected using autofluorescence to guide selection of beta cell areas of the islet. RNA was extracted and amplified with 2 rounds of T7 linear amplification. Two technical replicates were hybridized to Affymetrix U95Av2 arrays.
Project description:We have developed an in vitro culture system that allows us to expand progenitor cells from human islet preparations and differentiate them into insulin-producing cells. We noticed however, that cultures from individual islet preparations had very heterogeneous outcomes, from good differentiation to almost none. We therefore speculated that our progenitor cell cultures contained different kinds of cells and that the true endocrine progenitor cells are present in the successful cultures, but not in the unsuccessful ones. To address this issue and to begin to identify markers for the true endocrine progenitor cells we compared global gene expression between a very successful culture (final insulin-expression 10% of islets) and an unsuccessful one (final insulin-expression 0%). We also included RNA from freshly isolated islets for control purposes. The cultures from donor A yielded substantial differentiation, while the cultures from donor B showed no successful differentiation.
Project description:To establish changes in cardiac transcription profiles brought about by heart failure we collected myocardial samples from patients undergoing cardiac transplantation whose failure arises from different etiologies (e.g. idiopathic dilated cardiomyopathy, ischemic cardiomyopathy, alcoholic cardiomyopathy, valvular cardiomyopathy, and hypertrophic cardiomyopathy) and from "normal" organ donors whose hearts cannot be used for transplants. The transcriptional profile of the mRNA in these samples will be measured with gene array technology. Changes in transcriptional profiles can be correlated with the physiologic profile of heart-failure hearts acquired at the time of transplantation. Keywords: other
Project description:To identify a novel target for the treatment of heart failure, we examined gene expression in the failing heart. Among the genes analyzed, 12/15 lipoxygenase (12/15-LOX) was markedly up-regulated in heart failure. To determine whether increased expression of 12/15-LOX causes heart failure, we established transgenic mice that overexpressed 12/15-LOX in cardiomyocytes. Echocardiography showed that 12/15-LOX transgenic mice developed systolic dysfunction. Cardiac fibrosis increased in 12/15-LOX transgenic mice with advancing age, and was associated with the infiltration of macrophages. Consistent with these observations, cardiac expression of monocyte chemoattractant protein-1 (Mcp-1) was up-regulated in 12/15-LOX transgenic mice compared with wild-type mice. Treatment with 12-hydroxy-eicosatetraenotic acid, a major metabolite of 12/15-LOX, increased MCP-1 expression in cardiac fibroblasts and endothelial cells, but not in cardiomyocytes. Inhibition of Mcp-1 reduced the infiltration of macrophages into the myocardium and prevented both systolic dysfunction and cardiac fibrosis in 12/15-LOX transgenic mice. Likewise, disruption of 12/15-LOX significantly reduced cardiac Mcp-1 expression and macrophage infiltration, thereby improving systolic dysfunction induced by chronic pressure overload. Our results suggest that cardiac 12/15-LOX is involved in the development of heart failure and that inhibition of 12/15-LOX could be a novel treatment for this condition. Heart failure is still one of the leading causes of death worldwide. Therefore, it is important to elucidate the underlying mechanisms of heart failure and develop more effective treatments for this condition. To clarify the molecular mechanisms of heart failure, we performed microarray analysis using cardiac tissue samples obtained from a hypertensive heart failure model (Dahl salt-sensitive rats). ~300 genes showed significant changes of expression in the failing hearts compared with control hearts. Among the genes analyzed, 12/15-lipoxygenase (12/15-LOX) was most markedly up-regulated in failing hearts compared with control hearts .
Project description:The anti-diabetic drug and agonist of the peroxisome proliferator-activated receptor gamma (Pparg), rosiglitazone, was recently withdrawn in many countries because the drug use was associated with an increased risk of heart failure. To investigate underlying pathomechanisms, we chose 6-month-old apolipoprotein E (apoE)-deficient mice, which are prone to atherosclerosis and insulin resistance, and thereby mimic the risk profile of patients with cardiovascular disease. After 8 weeks of rosiglitazone treatment (30 mg/kg/day), echocardiography and histology analyses demonstrated that rosiglitazone had induced heart failure with cardiac dilation. Concomitantly, cardiac lipid overload and lipid-induced cardiomyocyte death developed. The microarray gene expression study of heart tissue from rosiglitazone-treated apoE-deficient mice relative to untreated apoE-deficient mice and non-transgenic B6 mice identified cardiac Pparg-dependent lipid metabolism genes in rosiglitazone-treated mice, which seem to trigger a major heart failure promoting pathway. Microarray gene expression profiling was performed with heart tissue isolated from three study groups: (i) rosiglitazone-treated 8-month-old apolipoprotein (apoE)-deficient mice with symptoms of heart failure, (ii) untreated 8-month-old apoE-deficient mice, and (iii) age-matched, untreated, non-transgenic B6 control mice.
Project description:Atopic dermatitis (AD) is a common pruritic dermatitis with macroscopically nonlesional skin that is often abnormal. Therefore, we used high-density oligonucleotide arrays to identify cutaneous gene transcription changes associated with early AD inflammation as potential disease control targets. Skin biopsy specimens analyzed included normal skin from five healthy nonatopic adults and both minimally lesional skin and nearby or contralateral nonlesional skin from six adult AD patients. Keywords: disease state analysis We used high-density oligonucleotide Affymetrix Human U133A GeneChip arrays to identify cutaneous gene transcription changes associated with early AD inflammation as potential disease control targets. Skin biopsy specimens analyzed included normal skin from five healthy nonatopic adults and both minimally lesional skin and nearby or contralateral nonlesional skin from six adult AD patients.
Project description:Microglia, the resident immune cells of the central nervous system (CNS), have two distinct phenotypes in the developing brain: amoeboid form, known to be amoeboid microglial cells (AMC) and ramified form, known to be ramified microglial cells (RMC) alongside several intermediate forms. The AMC are characterized by being proliferative, phagocytic and migratory whereas the RMC are quiescent and exhibit a slow turnover rate. The AMC transform into RMC with advancing age, and this transformation is indicative of the gradual shift in the microglial functions. Both AMC and RMC respond to CNS inflammation, and they become hypertrophic when they are activated by trauma, infection or neurodegenerative stimuli. The molecular mechanisms and functional significance of morphological transformation of microglia during normal development and in disease conditions is not clear. It is hypothesized that AMC and RMC are functionally regulated by a specific set of genes encoding various signaling molecules and transcription factors. To address this, we carried out cDNA microarray analysis using lectin-labeled AMC and RMC isolated from frozen tissue sections of the corpus callosum of 5-day and 4-week old rat brain respectively, by laser capture microdissection (LCM). The global gene expression profiles of both microglial phenotypes were compared and the differentially expressed genes in AMC and RMC were clustered based on their functional annotations. This genome wide comparative analysis helps in identifying genes that are specific to AMC and RMC. The novel and specific molecules identified in both microglial phenotypes can be targeted for therapeutic purposes in developing and adult brain diseases. We used microarrays to identify the genes specific to amoeboid and ramified microglia. RNA was isolated from the laser-captured amoeboid and ramified microglia from the corpus callosum of 5-day and 4-week old rat brain. The RNA was hybridised onto Affymetrix Rat 230 2.0 array.
Project description:Drought and salinity are two main abiotic-stresses negatively affecting crop growth and productivity worldwide with largely decreasing crop yields. The understanding of plant responses to stresses in physiology, genetics, and molecular biology will be greatly helpful to improve the tolerance of crops to abiotic-stresses through genetic engineering. To identify the genetic loci that control drought and salt tolerance in rice, we performed a large-scale screen for the mutants with altered drought and salt tolerance. A drought and salt tolerance (dst) mutant line was isolated. In this series, we compare the transcriptome of wild-type plant Zhonghua11 and dst mutants under the normal growth conditions. Keywords: genetic modification 6 samples (3 biological replicates for each line) were used in this experiment.