The oxt6 mutant is an oxidative stress-tolerant Arabidopsis mutant that is deficient in a polyadenylation factor subunit. Expression analysis suggests that impaired poly(A) site choice is responsible for the stress-tolerant phenotype.
A polyadenylation factor subunit implicated in regulating oxidative signaling in Arabidopsis thaliana.
No sample metadata fields
View SamplesRecent studies have been successful at utilizing ectopic expression of transcription factors to generate induced cardiomyocytes (iCMs) from fibroblasts, albeit at a low frequency in vitro. This work investigates the influence of small molecules that have been previously reported to improve differentiation to cardiomyocytes as well as reprogramming to iPSCs in conjunction with ectopic expression of the transcription factors Hand2, Nkx2.5, Gata4, Mef2C, and Tbx5 on the conversion to functional iCMs. We utilized a reporter system in which the calcium indicator GCaMP is driven by the cardiac Troponin T promoter to quantify iCM yield. The TGF inhibitor, SB431542 (SB), was identified as a small molecule capable of increasing the conversion of both mouse embryonic fibroblasts and adult cardiac fibroblasts to iCMs up to ~5 fold. Further characterization revealed that inhibition of TGF by SB early in the reprogramming process led to the greatest increase in conversion of fibroblasts to iCMs in a dose-responsive manner. Global transcriptional analysis at Day 3 post-induction of the transcription factors revealed an increased expression of genes associated with the development of cardiac muscle in the presence of SB compared to the vehicle control. Incorporation of SB in the reprogramming process increases the efficiency of iCM generation, one of the major goals necessary to enable the use of iCMs for discovery-based applications and for the clinic.
Inhibition of TGFβ signaling increases direct conversion of fibroblasts to induced cardiomyocytes.
Specimen part, Treatment
View SamplesTransdifferentiation has been recently described as a novel method for converting human fibroblasts into induced cardiomyocyte-like cells. Such an approach can produce differentiated cells to study physiology or pathophysiology, examine drug interactions or toxicities, and engineer tissues. Here we describe the transdifferentiation of human dermal fibroblasts towards the cardiac cell lineage via the induced expression of transcription factors (TFs) GATA4, TBX5, MEF2C, MYOCD, NKX2-5, and delivery of microRNAs miR-1 and miR-133a. Cells undergoing transdifferentiation expressed ACTN2 and TNNT2 and partially organized their cytoskeleton in a cross-striated manner. The conversion process was associated with significant upregulation of a cohort of cardiac-specific genes, activation of pathways associated with muscle contraction and physiology, and downregulation of fibroblastic markers. We used a genetically encoded calcium indicator and readily detected active calcium transients although no spontaneous contractions were observed in transdifferentiated cells. Finally, we determined that inhibition of Janus kinase 1, inhibition of glycogen synthase kinase 3, or addition of NRG1 significantly enhanced the efficiency of transdifferentiation. Overall, we describe a method for achieving transdifferentiation of human dermal fibroblasts into induced cardiomyocyte-like cells via transcription factor overexpression, microRNA delivery, and molecular pathway manipulation.
Core Transcription Factors, MicroRNAs, and Small Molecules Drive Transdifferentiation of Human Fibroblasts Towards The Cardiac Cell Lineage.
Specimen part, Treatment, Time
View SamplesModerate alcohol exposure during pregnancy can result in a heterogeneous range of neurobehavioural and cognitive effects, termed fetal alcohol spectrum disorders (FASD). We have developed a mouse model of FASD that involves moderate ethanol exposure throughout gestation achieved by voluntary maternal consumption. This model results in phenotypes relevant to FASD. Since ethanol is known to directly affect the expression of genes in the developing brain leading to abnormal cell death, changes to cell proliferation, migration, and differentiation, and potential changes to epigenetic patterning, we hypothesize that this leaves a long-term footprint on the adult brain. However, the long-term effects of prenatal ethanol exposure on brain gene expression, when behavioural phenotypes are apparent, are unclear.
Long-lasting alterations to DNA methylation and ncRNAs could underlie the effects of fetal alcohol exposure in mice.
Sex, Specimen part, Treatment
View SamplesThe developing brain is particularly sensitive to ethanol during the brain growth spurt or synaptogenesis (third human trimester equivalent). This has been shown to lead to abnormal brain development and behavioural changes in the adult mouse that are relevant to those seen in humans with fetal alcohol spectrum disorders (FASD). We evaluated the long-term (postnatal day 60 young adult) gene expression changes that occur in the brain due to ethanol exposure during synaptogenesis.
Long-lasting alterations to DNA methylation and ncRNAs could underlie the effects of fetal alcohol exposure in mice.
Treatment
View SamplesTransient over-expression of defined combinations of master regulator genes can effectively induce cellular reprogramming: the acquisition of an alternative predicted phenotype from a differentiated cell lineage. This can be of particular importance in cardiac regenerative medicine wherein the heart lacks the capacity to heal itself, but simultaneously contains a large pool of fibroblasts. In this study we determined the cardio-inducing capacity of ten transcription factors to actuate cellular reprogramming of mouse embryonic fibroblasts into cardiomyocyte-like cells. Over-expression of transcription factors MYOCD and SRF alone or in conjunction with Mesp1 and SMARCD3 significantly enhanced the basal but necessary cardio-inducing effect of the previously reported GATA4, TBX5, and MEF2C. In particular, combinations of five or seven transcription factors significantly enhanced the activation of cardiac reporter vectors, and induced an upregulation of cardiac-specific genes. Global gene expression analysis also demonstrated a significantly greater cardio-inducing effect when the transcription factors MYOCD and SRF were used. Detection of cross-striated cells was highly dependent on the cell culture conditions and was enhanced by the addition of valproic acid and JAK inhibitor. Although we detected Ca2+ transient oscillations in the reprogrammed cells, we did not detect significant changes in resting membrane potential or spontaneously contracting cells. This study further elucidates the cardio-inducing effect of the transcriptional networks involved in cardiac cellular reprogramming, contributing to the ongoing rational design of a robust protocol required for cardiac regenerative therapies.
Transcription factors MYOCD, SRF, Mesp1 and SMARCD3 enhance the cardio-inducing effect of GATA4, TBX5, and MEF2C during direct cellular reprogramming.
Specimen part
View SamplesA comprehensive omic, computational, and physiological approach was employed to examine the (previously unexplored) role of microRNAs (miRNAs) as regulators of IAS smooth muscle contractile phenotype and basal tone. MicroRNA profiling, genome wide expression, validation and network analyses were employed to assess changes in mRNA and miRNA expression in IAS smooth muscles from young vs. aging rats. Multiple miRNAs, including rno-miR-1, rno-miR-340-5p, rno-miR-185, rno-miR-199a-3p, rno-miR-200c, rno-miR-200b, rno-miR-31, rno-miR-133a and rno-miR-206 were found to be up-regulated in aging IAS. qRT-PCR confirmed the up-regulated expression of these miRNAs and down regulation of multiple, predicted targets (Eln, Col3a1, Col1a1, Zeb2, Myocd, SRF, Smad1, Smad2, RhoA/ROCK2, Fn1, Sm22-v2, Klf4, and Acta2) involved in regulation of SM contractility. Subsequent studies demonstrated an aging-associated increase in the expression of miR-133a, corresponding decreases in RhoA, ROCK2, MYOCD, SRF and SM22 protein expression, RhoA-signaling, and a decrease in basal and agonist (U-46619 (thromboxane A2 analog))-induced increase in the IAS tone. Moreover, in vitro transfection of miR-133a caused a dose-dependent increase of IAS tone in strips, which was reversed by anti-miR-133a. Lastly, in vivo perianal injection of anti-miR-133a reversed the loss of IAS tone associated with age. This work establishes the important regulatory effect of miRNA-133a on basal and agonist-stimulated IAS tone. Moreover, reversal of age-associated loss of tone via anti-miR delivery strongly implicates miR dysregulation as a causal factor in the aging-associated decrease in IAS tone, and suggests miR-133a is feasible therapeutic target in aging-associated rectoanal incontinence.
Aging-associated changes in microRNA expression profile of internal anal sphincter smooth muscle: Role of microRNA-133a.
Sex, Age, Specimen part, Disease
View SamplesC2C12 myoblasts were infected with a retrovirus expressing Pax7d or with an empty virus (puro) as a control. All of the samples originated from the same common pool of parental C2C12. This pool was split into six streams. A single prep of Pax7d-puro virus was split into three volumes and used to infect three of the streams. A single prep of puro-alone virus was similarly split in three and used to infect the remaining three streams. From the point of the infection forward each stream was maintained distinct from the others. Cells were infected and grown simultaneously under identical conditions.
Pax7 activates myogenic genes by recruitment of a histone methyltransferase complex.
No sample metadata fields
View SamplesDirect conversion of fibroblasts to induced cardiomyocytes (iCMs) has great potential for regenerative medicine. Recent publications have reported significant progress, but the evaluation of reprogramming has relied upon non-functional measures such as flow cytometry for cardiomyocyte markers or GFP expression driven by a cardiomyocyte-specific promoter. The issue is one of practicality: the most stringent measures - electrophysiology to detect cell excitation and the presence of spontaneously contracting myocytes - are not readily quantifiable in the large numbers of cells screened in reprogramming experiments. However, excitation and contraction are linked by a third functional characteristic of cardiomyocytes: the rhythmic oscillation of intracellular calcium levels. We set out to optimize direct conversion of fibroblasts to iCMs with a quantifiable calcium reporter to rapidly assess functional transdifferentiation. We constructed a reporter system in which the calcium indicator GCaMP is driven by the cardiomyocyte-specific Troponin T promoter. Using calcium activity as our primary outcome measure, we compared several published combinations of transcription factors along with novel combinations in mouse embryonic fibroblasts. The most effective combination consisted of Hand2, Nkx2.5, Gata4, Mef2c, and Tbx5 (HNGMT). This combination is >50-fold more efficient than GMT alone and produces iCMs with cardiomyocyte marker expression, robust calcium oscillation, and spontaneous beating that persists for weeks following inactivation of reprogramming factors. HNGMT is also significantly more effective than previously published factor combinations for the transdifferentiation of adult mouse cardiac fibroblasts to iCMs. Quantification of calcium function is a convenient and effective means for the identification and evaluation of cardiomyocytes generated by direct reprogramming. Using this stringent outcome measure, we conclude that HNGMT produces iCMs more efficiently than previously published methods.
Optimization of direct fibroblast reprogramming to cardiomyocytes using calcium activity as a functional measure of success.
No sample metadata fields
View SamplesIL-17 and TNF-alpha synergistically induce surface expression of IL-13Ra2 on primary lung fibroblasts, rendering them unresponsive to IL-13. Neutralizing antibodies to IL-13Ra2 restored IL-13-mediated signaling and transcriptome studies confirmed IL-13Ra2 is an IL-13 decoy receptor.
TNF-α/IL-17 synergy inhibits IL-13 bioactivity via IL-13Rα2 induction.
Specimen part, Cell line
View Samples