Long-read sequencing reveals the complex splicing profile of the psychiatric risk gene CACNA1C in human brain.

RNA splicing is a key mechanism linking genetic variation with psychiatric disorders. Splicing profiles are particularly diverse in brain and difficult to accurately identify and quantify. We developed a new approach to address this challenge, combining long-range PCR and nanopore sequencing with a novel bioinformatics pipeline. We identify the full-length coding transcripts of CACNA1C in human brain. CACNA1C is a psychiatric risk gene that encodes the voltage-gated calcium channel CaV1.2. We show that CACNA1C's transcript profile is substantially more complex than appreciated, identifying 38 novel exons and 241 novel transcripts. Importantly, many of the novel variants are abundant, and predicted to encode channels with altered function. The splicing profile varies between brain regions, especially in cerebellum. We demonstrate that human transcript diversity (and thereby protein isoform diversity) remains under-characterised, and provide a feasible and cost-effective methodology to address this. A detailed understanding of isoform diversity will be essential for the translation of psychiatric genomic findings into pathophysiological insights and novel psychopharmacological targets.

Identification of functional long non-coding RNAs in C. elegans.

BACKGROUND: Functional characterisation of the compact genome of the model organism Caenorhabditis elegans remains incomplete despite its sequencing 20 years ago. The last decade of research has seen a tremendous increase in the number of non-coding RNAs identified in various organisms. While we have mechanistic understandings of small non-coding RNA pathways, long non-coding RNAs represent a diverse class of active transcripts whose function remains less well characterised. RESULTS: By analysing hundreds of published transcriptome datasets, we annotated 3392 potential lncRNAs including 143 multi-exonic loci that showed increased nucleotide conservation and GC content relative to other non-coding regions. Using CRISPR/Cas9 genome editing, we generated deletion mutants for ten long non-coding RNA loci. Using automated microscopy for in-depth phenotyping, we show that six of the long non-coding RNA loci are required for normal development and fertility. Using RNA interference-mediated gene knock-down, we provide evidence that for two of the long non-coding RNA loci, the observed phenotypes are dependent on the corresponding RNA transcripts. CONCLUSIONS: Our results highlight that a large section of the non-coding regions of the C. elegans genome remains unexplored. Based on our in vivo analysis of a selection of high-confidence lncRNA loci, we expect that a significant proportion of these high-confidence regions is likely to have a biological function at either the genomic or the transcript level.

Physio-Genetic Dissection of Dark-Induced Leaf Senescence and Timing Its Reversal in Barley.

Barley crop model was analyzed for early and late events during the dark-induced leaf senescence (DILS) as well as for deciphering critical time limit for reversal of the senescence process. Chlorophyll fluorescence vitality index Rfd was determined as the earliest parameter that correlated well with the cessation of photosynthesis prior to microautophagy symptoms, initiation of DNA degradation, and severalfold increase in the endonuclease BNUC1. DILS was found characterized by up-regulation of processes that enable recycling of degraded macromolecules and metabolites, including increased NH4 + remobilization, gluconeogenesis, glycolysis, and partial up-regulation of glyoxylate and tricarboxylate acid cycles. The most evident differences in gene medleys between DILS and developmental senescence included hormone-activated signaling pathways, lipid catabolic processes, carbohydrate metabolic processes, low-affinity ammonia remobilization, and RNA methylation. The mega-autophagy symptoms were apparent much later, specifically on day 10 of DILS, when disruption of organelles-nucleus and mitochondria -became evident. Also, during this latter-stage programmed cell death processes, namely, shrinking of the protoplast, tonoplast interruption, and vacuole breakdown, chromatin condensation, more DNA fragmentation, and disintegration of the cell membrane were prominent. Reversal of DILS by re-exposure of the plants from dark to light was possible until but not later than day 7 of dark exposure and was accompanied by regained photosynthesis, increase in chlorophyll, and reversal of Rfd, despite activation of macro-autophagy-related genes.

Potential protective role of Grainyhead-like genes in the development of clear cell renal cell carcinoma.

The involvement of Grainyhead-like (GRHL) transcription factors in various cancers is well documented. However, little is known about their role in clear cell renal cell carcinoma (ccRCC). We discovered that the expression of two of these factors-GRHL1 and GRHL2-are downregulated in ccRCC samples, and their expression is correlated with the expression of VHL gene. This suggests a functional link between the GRHL transcription factors and one of the best known tumor suppressors. Although the GRHL genes are not mutated in ccRCC, some of the single nucleotide polymorphisms in these genes may indicate an increased risk of ccRCC development and/or may allow to assess patients' prognoses and predict their responses to various forms of therapy. Silencing of GRHL2 expression in non-tumorigenic kidney cell line results in increased cell proliferation, increased resistance to apoptosis, as well as changes in the levels of selected proteins involved in the pathogenesis of ccRCC. These changes support the potential role for GRHL2 as a suppressor of ccRCC.

Expression of pre-selected TMEMs with predicted ER localization as potential classifiers of ccRCC tumors.

BACKGROUND: VHL inactivation is the most established molecular characteristic of clear cell renal cell carcinoma (ccRCC), with only a few additional genes implicated in development of this kidney tumor. In recently published ccRCC gene expression meta-analysis study we identified a number of deregulated genes with limited information available concerning their biological role, represented by gene transcripts belonging to transmembrane proteins family (TMEMs). TMEMs are predicted to be components of cellular membranes, such as mitochondrial membranes, ER, lysosomes and Golgi apparatus. Interestingly, the function of majority of TMEMs remains unclear. Here, we analyzed expression of ten TMEM genes in the context of ccRCC progression and development, and characterized these proteins bioinformatically. METHODS: The expression of ten TMEMs (RTP3, SLC35G2, TMEM30B, TMEM45A, TMEM45B, TMEM61, TMEM72, TMEM116, TMEM207 and TMEM213) was measured by qPCR. T-test, Pearson correlation, univariate and multivariate logistic and Cox regression were used in statistical analysis. The topology of studied proteins was predicted with Metaserver, together with PSORTII, Pfam and Localizome tools. RESULTS: We observed significant deregulation of expression of 10 analyzed TMEMs in ccRCC tumors. Cluster analysis of expression data suggested the down-regulation of all tested TMEMs to be a descriptor of the most advanced tumors. Logistic and Cox regression potentially linked TMEM expression to clinical parameters such as: metastasis, Fuhrman grade and overall survival. Topology predictions classified majority of analyzed TMEMs as type 3 and type 1 transmembrane proteins, with predicted localization mainly in ER. CONCLUSIONS: The massive down-regulation of expression of TMEM family members suggests their importance in the pathogenesis of ccRCC and the bioinformatic analysis of TMEM topology implies a significant involvement of ER proteins in ccRCC pathology.

FUT11 as a potential biomarker of clear cell renal cell carcinoma progression based on meta-analysis of gene expression data.

In this paper, we provide a comprehensive summary of available clear cell renal cell carcinoma (ccRCC) microarray data in the form of meta-analysis of genes differentially regulated in tumors as compared to healthy tissue, using effect size to measure the strength of a relationship between the disease and gene expression. We identified 725 differentially regulated genes, with a number of interesting targets, such as TMEM213, SMIM5, or ATPases: ATP6V0A4 and ATP6V1G3, of which limited or no information is available in terms of their function in ccRCC pathology. Downregulated genes tended to represent pathways related to tissue remodeling, blood clotting, vasodilation, and energy metabolism, while upregulated genes were classified into pathways generally deregulated in cancers: immune system response, inflammatory response, angiogenesis, and apoptosis. One hundred fifteen deregulated genes were included in network analysis, with EGLN3, AP-2, NR3C1, HIF1A, and EPAS1 (gene encoding HIF2-α) as points of functional convergence, but, interestingly, 610 genes failed to join previously identified molecular networks. Furthermore, we validated the expression of 14 top deregulated genes in independent sample set of 32 ccRCC tumors by qPCR and tested if it could serve as a marker of disease progression. We found a correlation of high fucosyltransferase 11 (FUT11) expression with non-symptomatic course of the disease, which suggests that FUT11's expression might be potentially used as a biomarker of disease progression.

Integrative analysis of Paneth cell proteomic and transcriptomic data from intestinal organoids reveals functional processes dependent on autophagy.

Paneth cells are key epithelial cells that provide an antimicrobial barrier and maintain integrity of the small-intestinal stem cell niche. Paneth cell abnormalities are unfortunately detrimental to gut health and are often associated with digestive pathologies such as Crohn's disease or infections. Similar alterations are observed in individuals with impaired autophagy, a process that recycles cellular components. The direct effect of autophagy impairment on Paneth cells has not been analysed. To investigate this, we generated a mouse model lacking Atg16l1 specifically in intestinal epithelial cells, making these cells impaired in autophagy. Using three-dimensional intestinal organoids enriched for Paneth cells, we compared the proteomic profiles of wild-type and autophagy-impaired organoids. We used an integrated computational approach combining protein-protein interaction networks, autophagy-targeted proteins and functional information to identify the mechanistic link between autophagy impairment and disrupted pathways. Of the 284 altered proteins, 198 (70%) were more abundant in autophagy-impaired organoids, suggesting reduced protein degradation. Interestingly, these differentially abundant proteins comprised 116 proteins (41%) that are predicted targets of the selective autophagy proteins p62, LC3 and ATG16L1. Our integrative analysis revealed autophagy-mediated mechanisms that degrade key proteins in Paneth cell functions, such as exocytosis, apoptosis and DNA damage repair. Transcriptomic profiling of additional organoids confirmed that 90% of the observed changes upon autophagy alteration have effects at the protein level, not on gene expression. We performed further validation experiments showing differential lysozyme secretion, confirming our computationally inferred downregulation of exocytosis. Our observations could explain how protein-level alterations affect Paneth cell homeostatic functions upon autophagy impairment.This article has an associated First Person interview with the joint first authors of the paper.

Genetic characterization of Polish ccRCC patients: somatic mutation analysis of PBRM1, BAP1 and KDMC5, genomic SNP array analysis in tumor biopsy and preliminary results of chromosome aberrations analysis in plasma cell free DNA.

BACKGROUND: Mutation analysis and cytogenetic testing in clear cell renal cell carcinoma (ccRCC) is not yet implemented in a routine diagnostics of ccRCC. MATERIAL AND METHODS: We characterized the chromosomal alterations in 83 ccRCC tumors from Polish patients using whole genome SNP genotyping assay. Moreover, the utility of next generation sequencing of cell free DNA (cfDNA) in patients plasma as a potential tool for non-invasive cytogenetic analysis was tested. Additionally, tumor specific somatic mutations in PBRM1, BAP1 and KDM5C were determined. RESULTS: We confirmed a correlation between deletions at 9p and higher tumor size, and deletion of chromosome 20 and the survival time. In Fuhrman grade 1, only aberrations of 3p and 8p deletion, gain of 5q and 13q and gains of chromosome 7 and 16 were present. The number of aberrations increased with Fuhrman grade, all chromosomes displayed cytogenetic changes in G3 and G4. ccRCC specific chromosome aberrations were observed in cfDNA, although discrepancies were found between cfDNA and tumor samples. In total 12 common and 94 rare variants were detected in PBRM1, BAP1 and KDM5C, with four potentially pathogenic variants. We observed markedly lower mutation load in PBRM1. CONCLUSIONS: Cytogenetic analysis of cfDNA may allow more accurate diagnosis of tumor aberrations and therefore the correlation between the chromosome aberrations in cfDNA and clinical outcome should be studied in larger cohorts. The functional studies on in BAP1, KDM5C, PBRM1 mutations in large, independent sample set would be necessary for the assessment of their prognostic and diagnostic potential.

Consequences of the loss of the Grainyhead-like 1 gene for renal gene expression, regulation of blood pressure and heart rate in a mouse model.

AIM: The Grainyhead-like 1 (GRHL1) transcription factor is tissue-specific and is very highly expressed in the kidney. In humans the GRHL1 gene is located at the chromosomal position 2p25. A locus conferring increased susceptibility to essential hypertension has been mapped to 2p25 in two independent studies, but the causative gene has never been identified. Furthermore, a statistically significant association has been found between a polymorphism in the GRHL1 gene and heart rate regulation. The aim of our study was to investigate the physiological consequences of Grhl1 loss in a mouse model and ascertain whether Grhl1 may be involved in the regulation of blood pressure and heart rate. EXPERIMENTAL APPROACH: In our research we employed the Grhl1 "knock-out" mouse strain. We analyzed renal gene expression, blood pressure and heart rate in the Grhl1-null mice in comparison with their "wild-type" littermate controls. Most important results: The expression of many genes is altered in the Grhl1(-/-) kidneys. Some of these genes have previously been linked to blood pressure regulation. Despite this, the Grhl1-null mice have normal blood pressure and interestingly, increased heart rate. CONCLUSIONS: Our work did not discover any new evidence to suggest any involvement of Grhl1 in blood pressure regulation. However, we determined that the loss of Grhl1 influences the regulation of heart rate in a mouse model.

Genomics and epigenomics of clear cell renal cell carcinoma: recent developments and potential applications.

Majority of clear cell renal cell carcinomas (ccRCCs) are diagnosed in the advanced metastatic stage resulting in dramatic decrease of patient survival. Thereby, early detection and monitoring of the disease may improve prognosis and treatment results. Recent technological advances enable the identification of genetic events associated with ccRCC and reveal significant molecular heterogeneity of ccRCC tumors. This review summarizes recent findings in ccRCC genomics and epigenomics derived from chromosomal aberrations, DNA sequencing and methylation, mRNA, miRNA expression profiling experiments. We provide a molecular insight into ccRCC pathology and recapitulate possible clinical applications of genomic alterations as predictive and prognostic biomarkers.

The effect of mitotane on viability, steroidogenesis and gene expression in NCI­H295R adrenocortical cells.

Mitotane, also known as o,p'­DDD or (RS)­1­chl-oro­2­[2,2­dichloro­1­(4­chlorophenyl)­ethyl]­benzene, is an adrenal cortex-specific cytotoxic drug used in the therapy of adrenocortical carcinoma (ACC). The drug also inhibits steroidogenesis, however, the mechanisms of its anticancer and antisteroidogenic effects remain unknown. At present, data on the impact of mitotane on cell viability and the regulation of genes encoding proteins associated with steroids synthesis in the adrenal cortex, including cortisol and dehydroepiandrosterone sulfate (DHEAS), are limited and contradictory. In the present study, the effect of 24­h mitotane treatment on viability of the ACC cell line, NCI­H295R, was analyzed, identifying a decrease in cell viability and an increase in caspase­3 and ­7 activities. Mitotane treatment also led to decreased cortisol and DHEAS concentration in the culture media. Concomitantly, mitotane resulted in decreased mRNA levels of two cytochromes P450 (CYP11A1 and CYP17A1), mRNAs encoding proteins involved in the synthesis of cortisol and DHEAS. Mitotane did not affect mRNA levels of cyclin dependent kinase inhibitor 1A (encoding p21) and MYC (encoding cMyc). cMyc and p21 are key transcription factors associated with cell cycle regulation. However, mitotane inhibited expression of transforming growth factor ß1 gene, encoding a potent inhibitor of cell proliferation and steroidogenesis. PRKAR1A, a protein kinase A regulatory subunit, is involved in the activation of steroidogenesis. PRKAR1A mRNA levels were reduced following 24­h treatment with mitotane. Results indicate that mitotane markedly inhibited expression of genes involved in steroidogenesis, secretion of cortisol and DHEAS. Reduced expression of TGFB1 cannot account fully for the effect of mitotane on CYP11A1 and CYP17A1. We hypothesized that reduced viability of NCI­H295R cells in the presence of mitotane may be a result of apoptosis triggered by increased caspase­3 and ­7 activities. Since p21 and cMyc mRNA levels were stable in the presence of mitotane, the mechanism by which caspase­3 and ­7 are induced remains unknown.

The molecular basis of adrenocortical cancer.

Adrenocortical tumors (ACTs) are common, and most are benign adrenocortical adenomas (ACAs). Malignant adrenocortical carcinoma (ACC) is a rare tumor type and is observed at the rate of one or two cases per million annually. ACTs are classified as either ACAs or ACCs by histopathologic methods that are based on nine Weiss scoring criteria, including the nuclear grade, mitotic rate, presence of necrosis, and others. In this review, we describe the findings of studies that have examined the molecular basis of ACTs, and we compare transcriptome analysis with other diagnostic approaches. ACTs are occasionally difficult to classify. Therefore, molecular techniques, such as microarray analysis, have recently been applied to overcome some of these diagnostic problems. We also discuss the likelihood of the diagnosis and discernment between ACAs and ACCs based on the molecular tests. To show the recent progress in understanding the etiology of ACTs, we highlight the relationship between genetic analysis and transcriptome analysis. We attempt to understand the role of abnormal cell growth and steroid hormone secretion. Genetic and transcriptome analyses have improved our understanding of ACTs considerably, yet many unanswered questions remain.