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result(s) for
"Wahlestedt, Claes"
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Regulatory roles of natural antisense transcripts
2009
Natural antisense transcripts are frequently functional and are involved in regulating gene expression. The authors summarize the proposed actions of antisense transcript into four models, each corresponding to a putative regulatory mechanism for a subset of antisense transcripts.
Mammalian genomes encode numerous natural antisense transcripts, but the function of these transcripts is not well understood. Functional validation studies indicate that antisense transcripts are not a uniform group of regulatory RNAs but instead belong to multiple categories with some common features. Recent evidence indicates that antisense transcripts are frequently functional and use diverse transcriptional and post-transcriptional gene regulatory mechanisms to carry out a wide variety of biological roles.
Journal Article
Emerging treatment strategies for glioblastoma multiforme
by
Wahlestedt, Claes
,
Carlsson, Steven K
,
Brothers, Shaun P
in
Biomarkers
,
Biomedical Research - trends
,
Brain cancer
2014
Glioblastoma multiforme (GBM) is the deadliest form of brain tumor with a more than 90% 5‐year mortality. GBM has a paltry median survival of 12.6 months attributed to the unique treatment limitations such as the high average age of onset, tumor location, and poor current understandings of the tumor pathophysiology. The resection techniques, chemotherapic strategies, and radiation therapy currently used to treat GBM have slowly evolved, but the improvements have not translated to marked increases in patient survival. Here, we will discuss the recent progress in our understanding of GBM pathophysiology, and the diagnostic techniques and treatment options. The discussion will include biomarkers, tumor imaging, novel therapies such as monoclonal antibodies and small‐molecule inhibitors, and the heterogeneity resulting from the GBM cancer stem cell population.
Graphical Abstract
A comprehensive overview and discussion of our current understanding of glioblastoma multiforme (GBM) pathophysiology and heterogeneity, diagnostic techniques and treatment options, including novel therapies such as monoclonal antibodies and small‐molecule inhibitors.
Journal Article
Personalized medicine in psychiatry: problems and promises
by
Nemeroff, Charles B
,
Wahlestedt, Claes
,
Ozomaro, Uzoezi
in
Biomarkers - analysis
,
Biomedicine
,
Bipolar disorder
2013
The central theme of personalized medicine is the premise that an individual’s unique physiologic characteristics play a significant role in both disease vulnerability and in response to specific therapies. The major goals of personalized medicine are therefore to predict an individual’s susceptibility to developing an illness, achieve accurate diagnosis, and optimize the most efficient and favorable response to treatment. The goal of achieving personalized medicine in psychiatry is a laudable one, because its attainment should be associated with a marked reduction in morbidity and mortality. In this review, we summarize an illustrative selection of studies that are laying the foundation towards personalizing medicine in major depressive disorder, bipolar disorder, and schizophrenia. In addition, we present emerging applications that are likely to advance personalized medicine in psychiatry, with an emphasis on novel biomarkers and neuroimaging.
Journal Article
Serum long noncoding RNA HOTAIR as a novel diagnostic and prognostic biomarker in glioblastoma multiforme
by
Tan, Sze Kiat
,
Wahlestedt, Claes
,
Ayad, Nagi G.
in
Analysis
,
Antisense RNA
,
Biological markers
2018
Glioblastoma multiforme (GBM) is the most common and aggressive malignant adult primary brain tumor. Despite surgical resection followed by radiotherapy and chemotherapy, the median survival rate is approximately 14 months. Although experimental therapies are in clinical trials for GBM, there is an urgent need for a peripheral GBM biomarker for measuring treatment response. As we have previously demonstrated that the long noncoding RNA HOX Transcript Antisense Intergenic RNA, or HOTAIR, is dysregulated in GBM and required for GBM cell proliferation, we hypothesized that HOTAIR expression may be utilized as a peripheral biomarker for GBM. HOTAIR expression was measured in serum from 43 GBM and 40 controls using quantitative real-time PCR (qRT-PCR). The PCR products were subsequently subcloned into pCR™4-TOPO®TA vectors for DNA sequencing. A ROC curve was also generated to examine HOTAIR’s prognostic value. The amount of HOTAIR in serum exosomes and exosome-depleted supernatant was calculated by qRT-PCR. The relative HOTAIR expression was also investigated in 15 pairs of GBM serum and tumors. We detected HOTAIR in serum from GBM patients. HOTAIR levels in serum samples from GBM patients was significantly higher than in the corresponding controls (
P
< 0.0001). The area under the ROC curve distinguishing GBM patients from controls was 0.913 (95% CI: 0.845–0.982,
P
< 0.0001), with 86.1% sensitivity and 87.5% specificity at the cut-off value of 10.8. HOTAIR expression was significantly correlated with high grade brain tumors. In addition,
Pearson
correlation analysis indicated a medium correlation of serum HOTAIR levels and the corresponding tumor HOTAIR levels (
r
= 0.734,
P
< 0.01). We confirmed via sequencing that the amplified HOTAIR from serum contained the HOTAIR sequence and maps to the known HOTAIR locus at 12q13. The serum-derived exosomes contain HOTAIR and the purified exosomes were validated by western blot and nanoparticle tracking analysis. Importantly, our results demonstrate that serum HOTAIR can be used as a novel prognostic and diagnostic biomarker for GBM.
Journal Article
Altering the course of schizophrenia: progress and perspectives
by
Marin, Oscar
,
Meyer-Lindenberg, Andreas
,
Patterson, Paul
in
631/154/109
,
631/378/1689
,
692/308/153
2016
Key Points
Schizophrenia is a debilitating and chronic disorder that is accompanied by psychosis and a broad spectrum of behavioural, cognitive and social deficits. It usually strikes in young adulthood. Currently, treatment is exclusively symptomatic, and medication has no direct, lasting influence on causal pathophysiology.
Improved knowledge of the developmental anomalies provoked by genetic, epigenetic and environmental triggers of schizophrenia has fostered interest in potential 'disease-modifying' strategies for either slowing its progression or preventing its appearance in vulnerable young adults.
Although awaiting further confirmation, clinical studies of pharmacotherapeutic and psychosocial and/or cognitive-behavioural interventions in young, high-risk individuals seeking help have collectively yielded evidence for a reduction in the transition to psychosis.
Nonetheless, only a third or so of clinically high-risk individuals convert, so it is important to improve the prediction of transition at the level of individuals by the use of biomarkers. Multi-modal approaches combining, for example, circulating biomarkers, sensory/cognitive deficits and brain imaging hold particular promise.
Although animal models for schizophrenia have limitations, diverse pharmacological treatments applied during adolescence preclude the appearance of a schizophrenia-like phenotype in adult rodents.
Studies exploiting these
in vivo
models, as well as novel cellular paradigms such as human induced pluripotent stem cells, are refining our understanding of the cellular substrates leading to schizophrenia, and hence unveiling potentially novel targets for medication.
In conclusion, though much work still remains to be undertaken, recent progress is raising the hope that it may eventually be possible to interrupt the course of schizophrenia, as well as other disorders characterized by psychosis. Of particular interest would be hybrid strategies that both relieve distress in young, at-risk individuals and reduce their conversion.
Advances in the understanding of the genetic and environmental causes of schizophrenia, and their relationship to aberrant patterns of neurodevelopment, have led to growing interest in the possibility that 'disease-modifying' strategies could alter the course to — and of — this debilitating disorder, rather than just alleviating its symptoms. This article provides a broad-based consideration of the challenges and opportunities inherent in such efforts.
Despite a lack of recent progress in the treatment of schizophrenia, our understanding of its genetic and environmental causes has considerably improved, and their relationship to aberrant patterns of neurodevelopment has become clearer. This raises the possibility that 'disease-modifying' strategies could alter the course to — and of — this debilitating disorder, rather than simply alleviating symptoms. A promising window for course-altering intervention is around the time of the first episode of psychosis, especially in young people at risk of transition to schizophrenia. Indeed, studies performed in both individuals at risk of developing schizophrenia and rodent models for schizophrenia suggest that pre-diagnostic pharmacotherapy and psychosocial or cognitive-behavioural interventions can delay or moderate the emergence of psychosis. Of particular interest are 'hybrid' strategies that both relieve presenting symptoms and reduce the risk of transition to schizophrenia or another psychiatric disorder. This Review aims to provide a broad-based consideration of the challenges and opportunities inherent in efforts to alter the course of schizophrenia.
Journal Article
Therapeutic potential of neuropeptide Y (NPY) receptor ligands
2010
Neuropeptide Y (NPY) is widely distributed in the human body and contributes to a vast number of physiological processes. Since its discovery, NPY has been implicated in metabolic regulation and, although interest in its role in central mechanisms related to food intake and obesity has somewhat diminished, the topic remains a strong focus of research concerning NPY signalling. In addition, a number of other uses for modulators of NPY receptors have been implied in a range of diseases, although the development of NPY receptor ligands has been slow, with no clinically approved receptor therapeutics currently available. Nevertheless, several interesting small molecule compounds, notably Y2 receptor antagonists, have been published recently, fueling optimism in the field. Herein we review the role of NPY in the pathophysiology of a number of diseases and highlight instances where NPY receptor signalling systems are attractive therapeutic targets.
Journal Article
shinyheatmap: Ultra fast low memory heatmap web interface for big data genomics
by
Khomtchouk, Bohdan B.
,
Hennessy, James R.
,
Wahlestedt, Claes
in
Algorithms
,
Analysis
,
Analytics
2017
Transcriptomics, metabolomics, metagenomics, and other various next-generation sequencing (-omics) fields are known for their production of large datasets, especially across single-cell sequencing studies. Visualizing such big data has posed technical challenges in biology, both in terms of available computational resources as well as programming acumen. Since heatmaps are used to depict high-dimensional numerical data as a colored grid of cells, efficiency and speed have often proven to be critical considerations in the process of successfully converting data into graphics. For example, rendering interactive heatmaps from large input datasets (e.g., 100k+ rows) has been computationally infeasible on both desktop computers and web browsers. In addition to memory requirements, programming skills and knowledge have frequently been barriers-to-entry for creating highly customizable heatmaps.
We propose shinyheatmap: an advanced user-friendly heatmap software suite capable of efficiently creating highly customizable static and interactive biological heatmaps in a web browser. shinyheatmap is a low memory footprint program, making it particularly well-suited for the interactive visualization of extremely large datasets that cannot typically be computed in-memory due to size restrictions. Also, shinyheatmap features a built-in high performance web plug-in, fastheatmap, for rapidly plotting interactive heatmaps of datasets as large as 105-107 rows within seconds, effectively shattering previous performance benchmarks of heatmap rendering speed.
shinyheatmap is hosted online as a freely available web server with an intuitive graphical user interface: http://shinyheatmap.com. The methods are implemented in R, and are available as part of the shinyheatmap project at: https://github.com/Bohdan-Khomtchouk/shinyheatmap. Users can access fastheatmap directly from within the shinyheatmap web interface, and all source code has been made publicly available on Github: https://github.com/Bohdan-Khomtchouk/fastheatmap.
Journal Article
Inhibition of natural antisense transcripts in vivo results in gene-specific transcriptional upregulation
by
Brothers, Shaun P
,
Faghihi, Mohammad Ali
,
Fatemi, Roya Pedram
in
631/337
,
631/378/1686
,
631/61/191
2012
Methods for specific gene silencing have advanced as far as clinical trials, but a similar set of tools does not exist for increasing gene expression. Modarresi
et al
. demonstrate gene-specific upregulation
in vivo
by treating mice with oligonucleotides that inhibit the function of natural antisense transcripts.
The ability to specifically upregulate genes
in vivo
holds great therapeutic promise. Here we show that inhibition or degradation of natural antisense transcripts (NATs) by single-stranded oligonucleotides or siRNAs can transiently and reversibly upregulate locus-specific gene expression. Brain-derived neurotrophic factor (BDNF) is normally repressed by a conserved noncoding antisense RNA transcript,
BDNF
-AS. Inhibition of this transcript upregulates
BDNF
mRNA by two- to sevenfold, alters chromatin marks at the
BDNF
locus, leads to increased protein levels and induces neuronal outgrowth and differentiation both
in vitro
and
in vivo
. We also show that inhibition of NATs leads to increases in glial-derived neurotrophic factor (GDNF) and ephrin receptor B2 (EPHB2) mRNA. Our data suggest that pharmacological approaches targeting NATs can confer locus-specific gene upregulation effects.
Journal Article
Defective HNF4alpha-dependent gene expression as a driver of hepatocellular failure in alcoholic hepatitis
2019
Alcoholic hepatitis (AH) is a life-threatening condition characterized by profound hepatocellular dysfunction for which targeted treatments are urgently needed. Identification of molecular drivers is hampered by the lack of suitable animal models. By performing RNA sequencing in livers from patients with different phenotypes of alcohol-related liver disease (ALD), we show that development of AH is characterized by defective activity of liver-enriched transcription factors (LETFs). TGF
β
1 is a key upstream transcriptome regulator in AH and induces the use of HNF4
α
P2 promoter in hepatocytes, which results in defective metabolic and synthetic functions. Gene polymorphisms in LETFs including HNF4
α
are not associated with the development of AH. In contrast, epigenetic studies show that AH livers have profound changes in DNA methylation state and chromatin remodeling, affecting HNF4
α
-dependent gene expression. We conclude that targeting TGF
β
1 and epigenetic drivers that modulate HNF4
α
-dependent gene expression could be beneficial to improve hepatocellular function in patients with AH.
Alcoholic hepatitis, a common cause of liver failure, lacks effective treatment. Here, the authors show altered hepatic HNF4a isoform expression and hypermethylation of its target genes in patients. HNF4a dysregulation is improved in vitro by TGFb or PPARg modulation suggesting potential therapeutic avenues.
Journal Article
Bromodomain protein BRD4 controls HOTAIR, a long noncoding RNA essential for glioblastoma proliferation
by
Ricardo Komotar
,
Georges St. Laurent
,
Claude-Henry Volmar
in
Animals
,
antisense RNA
,
Apoptosis - genetics
2015
Bromodomain and extraterminal (BET) domain proteins have emerged as promising therapeutic targets in glioblastoma and many other cancers. Small molecule inhibitors of BET bromodomain proteins reduce expression of several oncogenes required for Glioblastoma Multiforme (GBM) progression. However, the mechanism through which BET protein inhibition reduces GBM growth is not completely understood. Long noncoding RNAs (lncRNAs) are important epigenetic regulators with critical roles in cancer initiation and malignant progression, but mechanistic insight into their expression and regulation by BET bromodomain inhibitors remains elusive. In this study, we used Helicos single molecule sequencing to comprehensively profile lncRNAs differentially expressed in GBM, and we identified a subset of GBM-specific lncRNAs whose expression is regulated by BET proteins. Treatment of GBM cells with the BET bromdomain inhibitor I-BET151 reduced levels of the tumor-promoting lncRNA HOX transcript antisense RNA (HOTAIR) and restored the expression of several other GBM down-regulated lncRNAs. Conversely, overexpression of HOTAIR in conjunction with I-BET151 treatment abrogates the antiproliferative activity of the BET bromodomain inhibitor. Moreover, chromatin immunoprecipitation analysis demonstrated binding of Bromodomain Containing 4 (BRD4) to the HOTAIR promoter, suggesting that BET proteins can directly regulate lncRNA expression. Our data unravel a previously unappreciated mechanism through which BET proteins control tumor growth of glioblastoma cells and suggest that modulation of lncRNA networks may, in part, mediate the antiproliferative effects of many epigenetic inhibitors currently in clinical trials for cancer and other diseases.
Journal Article