Project description:Mechanical unloading by ventricular assist devices (VAD) leads to significant gene-expression changes often summarized as reverse remodeling. However, little is known on individual transcriptome changes during VAD-support and its relationship to non-failing hearts (NF). In addition no data are available for the transcriptome regulation during non-pulsatile VAD-support. Therefore we analysed the gene-expression patterns of 30 paired samples from VAD-supported (including 8 non-pulsatile VADs) and 8 non-failing control hearts (NF) using the first total human genome-array available. Transmural myocardial samples were collected for RNA-isolation. RNA was isolated by commercial methods and processed according to chip-manufacturer recommendations. cRNA were hybridized on Affymetrix HG-U133 Plus 2.0 arrays, providing coverage of the whole human genome Array. Data was analyzed using Microarray Analysis Suite 5.0 (Affymetrix) and clustered by Expressionist software (Genedata). 352 transcripts were differentially regulated between samples from VAD-implantation and NF, whereas 510 were significantly regulated between VAD-transplantation and NF (paired t-test p<0.001, fold change >=1.6). Remarkably, only a minor fraction of 111 transcripts was regulated in heart failure (HF) and during VAD-support. Unsupervised hierarchical clustering of paired VAD- and NF-samples revealed separation of HF- and NF- samples, however individual differentiation of VAD-implantation and VAD-transplantation was not accomplished. Clustering of pulsatile and non-pulsatile VAD did not lead to robust separation of gene expression patterns. During VAD-support myocardial gene expression changes do not indicate reversal of the HF-phenotype, but reveal a distinct HF-related pattern. Transcriptome analysis of pulsatile and non-pulsatile VAD-supported hearts did not provide evidence for a pump-mode specific transcriptome pattern. Microarrays were used to elucidate the differences between non-failing control hearts and those, suffering from end-stage heart failure pre and post mechanical unloading.

Project description:Alzheimer’s disease (AD) and vascular dementia (VaD) are the two most common forms of dementia, neither of which can be effectively treated. There is growing evidence on vascular contributions to cognitive impairment and dementia such as AD, but their pathogenic molecular links are not defined yet. Notably, neurofibrillary tangles made of hyperphosphorylated tau (P-tau) are a hallmark lesion of AD, but are not found in VaD. Although brain ischemia induces some tau changes and tau knockout reduces stroke-induced acute brain damage, little is known about the role of tau in mediating progression from vascular insufficiency to later development of VaD. Cis P-tau is a pre-tangle pathology in AD and an early driver of neurodegeneration resulting from brain injury, but its role in AD treatment or in VaD is unknown. Here we identify cis P-tau as an antibody-neutralizable major common early driver of AD and VaD. We show that cis P-tau elimination using cis antibody not only prevents, but also treats AD-like neurodegeneration and memory loss in a hTau mouse model of AD. Purified cis P-tau causes and spreads neurodegeneration with behavioral changes when injected into wild-type mouse brains, but is prevented by cis antibody. Surprisingly, we also find robust cis P-tau with no evidence of tau tangles in human VaD brains and a mouse model of chronic cerebral hypoperfusion that mimics key aspects of clinical VaD. Cis mAb treatment of hypoperfusive mice for 1 or 6 months blocks VaD-like neuropathological and functional outcomes. Single-cell transcriptomic profiling reveals that cerebral hypoperfusion induces numerous global changes in diverse brain cells including those of human AD brains. Remarkably, ~90% of these global changes are fully recovered with cis antibody, correlating with tau expression in cells. Thus, cis P-tau is a major common early driver of AD and VaD, and cis antibody has a potential role in the early detection, prevention and treatment of these devastating diseases.

Project description:The objective of this study was to understand the genetic mechanisms of Vitamin-A-Deficiency (VAD)-induced arrest of spermatogonial stem-cell differentiation. Vitamin A and its derivatives (the retinoids) participate in many physiological processes including vision, cellular differentiation and reproduction. VAD affects spermatogenesis, the subject of our present study. Spermatogenesis is a highly regulated process of differentiation and complex morphologic alterations that, in the postnatal testis, leads to the formation of sperm in the seminiferous epithelium. VAD causes early cessation of spermatogenesis, characterized by degeneration of meiotic germ cells, leading to seminiferous tubules containing mostly type A spermatogonia and Sertoli cells. In this study, we investigated the molecular basis of VAD on spermatogenesis in mice. We used adult Balb/C mice fed with a Control or VAD diet for an extended period of time (8-28 weeks) and selected two time points (18 and 25 weeks) for microarray analysis. To understand the effect of VAD on the spermatogonial stem cell transcriptome, we studied isolated pure populations of spermatogonia from control and vitamin-A-deficient mice from two representative time points (18 and 25 weeks) using Affymetrix GeneChip microarrays. We identified target genes involved in the arrest of spermatogonial differentiation and spermatogenesis. Our results establish a better understanding of the chronology and magnitude of the consequences of VAD on mouse testes and add to the current knowledge of the molecular regulatory mechanisms of germ cell development. Spermatogonia were isolated by the STATPUT procedure with minor modifications. VAD mice were sacrificed at 18 and 25 weeks of VAD treatment for spermatogonia isolation. Decapsulated testes from 2 mice were suspended in RPMI medium containing collagenase (0.6 mg/ml), Hyaluronidase (0.12 mg/ml) and DNAse I (1.25 mg/ml) and incubated at 37ºC for 30 minutes in a shaking water bath. The tissues were then allowed to come down the tube and the supernatant (containing interstitial cells) was removed. The pellet was incubated with 3 ml of 0.25% Trypsin /EDTA (GIBCO, Invitrogen, USA), in the presence of DNAse I (0.2 mg/ml) at 37ºC for 15 minutes in a shaking water bath. The dispersed cells were washed twice with RPMI medium containing 10% heat inactivated FBS to neutralize the protease activity, and filtered through a sterile 0.22 nylon to remove any undigested fragments. Cells of the dissociated seminiferous epithelium were then plated overnight in a 34ºC 3% CO2 incubator. The following day, germ cells, in suspension, were separated by sedimentation with use of a 2-4% BSA gradient. The cells were allowed to sediment for a standard period of 2.5 h, and fractions of 2-ml volume were collected. The cells of each fraction were examined under a phase contrast microscope, and fractions containing cells of similar size and morphology were pooled and spun down by low-speed centrifugation. Purity of spermatogonia was estimated and was routinely higher than 90%. Total RNA was extracted from the isolated germ cells using TRIzol ® Reagent, and cleaned with RNeasy minicolumns. RNA content was determined by measurement of optical density at 260 nm. Only the RNA samples showing an OD 260/280 ratio higher than 1.8 were used for microarray hybridization. Raw expression values in Affymetrix CEL file format were generated by GeneChip Operating Software.

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RNA-seq of AD and VaD model animals

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