Environmental Temperature Variation Affects Brain Lipid Composition in Adult Zebrafish (Danio rerio).

This study delves deeper into the impact of environmental temperature variations on the nervous system in teleost fish. Previous research has demonstrated that exposing adult zebrafish (Danio rerio) to 18 °C and 34 °C for 4 or 21 days induces behavioural changes compared to fish kept at a control temperature of 26 °C, suggesting alterations in the nervous system. Subsequent studies revealed that these temperature conditions also modify brain protein expression, indicating potential neurotoxic effects. The primary aim of this work was to investigate the effects of prolonged exposure (21 days) to 18 °C or 34 °C on the brain lipidomes of adult zebrafish compared to a control temperature. Analysis of the brain lipidome highlighted significant alteration in the relative abundances of specific lipid molecules at 18 °C and 34 °C, confirming distinct effects induced by both tested temperatures. Exposure to 18 °C resulted in an increase in levels of phospholipids, such as phosphatidylethanolamine, alongside a general reduction in levels of sphingolipids, including sphingomyelin. Conversely, exposure to 34 °C produced more pronounced effects, with increases in levels of phosphatidylethanolamine and those of various sphingolipids such as ceramide, gangliosides, and sphingomyelin, alongside a reduction in levels of ether phospholipids, including lysophosphatidylethanolamine ether, phosphatidylethanolamine ether, and phosphatidylglycerol ether, as well as levels of glycolipids like monogalactosyldiacylglycerol. These results, when integrated with existing proteomic and behavioural data, offer new insights into the effects of thermal variations on the nervous system in teleost fish. Specifically, our proteomic and lipidomic findings suggest that elevated temperatures may disrupt mitochondrial function, increase neuronal susceptibility to oxidative stress and cytotoxicity, alter axonal myelination, impair nerve impulse transmission, hinder synapse function and neurotransmitter release, and potentially lead to increased neuronal death. These findings are particularly relevant in the fields of cell biology, neurobiology, and ecotoxicology, especially in the context of global warming.

Selection of suitable reference genes for gene expression studies in HMC3 cell line by quantitative real-time RT-PCR.

Microglia represent the primary immune defense system within the central nervous system and play a role in the inflammatory processes occurring in numerous disorders, such as Parkinson's disease (PD). PD onset and progression are associated with factors considered possible causes of neuroinflammation, i.e. genetic mutations. In vitro models of microglial cells were established to identify specific molecular targets in PD through the analysis of gene expression data. Recently, the Human Microglial Clone 3 cell line (HMC3) has been characterized and a new human microglia model has emerged. Here we perform RT-qPCR analyses to evaluate the expression of ten reference genes in HMC3, untreated or stimulated to a pro-inflammatory status. The comparative ∆CT method, BestKeeper, Normfinder, geNorm and RefFinder algorithms were used to assess the stability of the candidate genes. The results showed that the most suitable internal controls are HPRT1, RPS18 and B2M genes. In addition, the most stable and unstable reference genes were used to normalize the expression of a gene of interest in HMC3, resulting in a difference in the statistical significance in cells treated with Rotenone. This is the first reference gene validation study in HMC3 cell line in pro-inflammatory status and can contribute to more reliable gene expression analysis in the field of neurodegenerative and neuroinflammatory research.

PROTAC-Induced Glycogen Synthase Kinase 3ß Degradation as a Potential Therapeutic Strategy for Alzheimer's Disease.

Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine kinase and an attractive therapeutic target for Alzheimer's disease. Based on proteolysis-targeting chimera (PROTAC) technology, a small set of novel GSK-3ß degraders was designed and synthesized by linking two different GSK-3ß inhibitors, SB-216763 and tideglusib, to pomalidomide, as E3 recruiting element, through linkers of different lengths. Compound 1 emerged as the most effective PROTAC being nontoxic up to 20 µM to neuronal cells and already able to degrade GSK-3ß starting from 0.5 µM in a dose-dependent manner. PROTAC 1 significantly reduced the neurotoxicity induced by Aß25-35 peptide and CuSO4 in SH-SY5Y cells in a dose-dependent manner. Based on its encouraging features, PROTAC 1 may serve as a starting point to develop new GSK-3ß degraders as potential therapeutic agents.

Brain Proteome and Behavioural Analysis in Wild Type, BDNF+/- and BDNF-/- Adult Zebrafish (Danio rerio) Exposed to Two Different Temperatures.

Experimental evidence suggests that environmental stress conditions can alter the expression of BDNF and that the expression of this neurotrophin influences behavioural responses in mammalian models. It has been recently demonstrated that exposure to 34 °C for 21 days alters the brain proteome and behaviour in zebrafish. The aim of this work was to investigate the role of BDNF in the nervous system of adult zebrafish under control and heat treatment conditions. For this purpose, zebrafish from three different genotypes (wild type, heterozygous BDNF+/- and knock out BDNF-/-) were kept for 21 days at 26 °C or 34 °C and then euthanized for brain molecular analyses or subjected to behavioural tests (Y-maze test, novel tank test, light and dark test, social preference test, mirror biting test) for assessing behavioural aspects such as boldness, anxiety, social preference, aggressive behaviour, interest for the novel environment and exploration. qRT-PCR analysis showed the reduction of gene expression of BDNF and its receptors after heat treatment in wild type zebrafish. Moreover, proteomic analysis and behavioural tests showed genotype- and temperature-dependent effects on brain proteome and behavioural responding. Overall, the absent expression of BDNF in KO alters (1) the brain proteome by reducing the expression of proteins involved in synapse functioning and neurotransmitter-mediated transduction; (2) the behaviour, which can be interpreted as bolder and less anxious and (3) the cellular and behavioural response to thermal treatment.

Loss of circadian rhythmicity in bdnf knockout zebrafish larvae.

Brain-derived neurotrophic factor (BDNF) plays a pivotal role in neuronal growth and differentiation, neuronal plasticity, learning, and memory. Using CRISPR/Cas9 technology, we generated a vital Bdnf null mutant line in zebrafish and carried out its molecular and behavioral characterization. Although no defects are evident on a morphological inspection, 66% of coding genes and 37% of microRNAs turned out to be differentially expressed in bdnf -/- compared with wild type sibling embryos. We deeply investigated the circadian clock pathway and confirmed changes in the rhythmic expression of clock (arntl1a, clock1a and clock2) and clock-controlled (aanat2) genes. The modulatory role of Bdnf on the zebrafish circadian clock was then validated by behavioral tests highlighting the absence of circadian activity rhythms in bdnf -/- larvae. The circadian behavior was partially rescued by pharmacological treatment. The bdnf -/- zebrafish line presented here is the first valuable and stable vertebrate model for the study of BDNF-related neurodevelopmental diseases.

Sex-Specific Transcriptome Differences in Human Adipose Mesenchymal Stem Cells.

In humans, sexual dimorphism can manifest in many ways and it is widely studied in several knowledge fields. It is increasing the evidence that also cells differ according to sex, a correlation still little studied and poorly considered when cells are used in scientific research. Specifically, our interest is on the sex-related dimorphism on the human mesenchymal stem cells (hMSCs) transcriptome. A systematic meta-analysis of hMSC microarrays was performed by using the Transcriptome Mapper (TRAM) software. This bioinformatic tool was used to integrate and normalize datasets from multiple sources and allowed us to highlight chromosomal segments and genes differently expressed in hMSCs derived from adipose tissue (hADSCs) of male and female donors. Chromosomal segments and differentially expressed genes in male and female hADSCs resulted to be related to several processes as inflammation, adipogenic and neurogenic differentiation and cell communication. Obtained results lead us to hypothesize that the donor sex of hADSCs is a variable influencing a wide range of stem cell biologic processes. We believe that it should be considered in biologic research and stem cell therapy.

Correction to "Discovery of the First-in-Class GSK-3ß/HDAC Dual Inhibitor as Disease-Modifying Agent To Combat Alzheimer's Disease".

[This corrects the article DOI: 10.1021/acsmedchemlett.8b00507.].

Discovery of the First-in-Class GSK-3ß/HDAC Dual Inhibitor as Disease-Modifying Agent To Combat Alzheimer's Disease.

Several evidence pointed out the role of epigenetics in Alzheimer's disease (AD) revealing strictly relationships between epigenetic and "classical" AD targets. Based on the reported connection among histone deacetylases (HDACs) and glycogen synthase kinase 3ß (GSK-3ß), herein we present the discovery and the biochemical characterization of the first-in-class hit compound able to exert promising anti-AD effects by modulating the targeted proteins in the low micromolar range of concentration. Compound 11 induces an increase in histone acetylation and a reduction of tau phosphorylation. It is nontoxic and protective against H2O2 and 6-OHDA stimuli in SH-SY5Y and in CGN cell lines, respectively. Moreover, it promotes neurogenesis and displays immunomodulatory effects. Compound 11 shows no lethality in a wt-zebrafish model (<100 µM) and high water solubility.

HDAC8 regulates canonical Wnt pathway to promote differentiation in skeletal muscles.

Histone deacetylase 8 (HDAC8) is a class 1 histone deacetylase and a member of the cohesin complex. HDAC8 is expressed in smooth muscles, but its expression in skeletal muscle has not been described. We have shown for the first time that HDAC8 is expressed in human and zebrafish skeletal muscles. Using RD/12 and RD/18 rhabdomyosarcoma cells with low and high differentiation potency, respectively, we highlighted a specific correlation with HDAC8 expression and an advanced stage of muscle differentiation. We inhibited HDAC8 activity through a specific PCI-34051 inhibitor in murine C2C12 myoblasts and zebrafish embryos, and we observed skeletal muscles differentiation impairment. We also found a positive regulation of the canonical Wnt signaling by HDAC8 that might explain muscle differentiation defects. These findings suggest a novel mechanism through which HDAC8 expression, in a specific time window of skeletal muscle development, positively regulates canonical Wnt pathway that is necessary for muscle differentiation.

Sex-Specific Transcriptome Differences in Substantia Nigra Tissue: A Meta-Analysis of Parkinson's Disease Data.

Parkinson's disease (PD) is one of the most common progressive neurodegenerative diseases. Clinical and epidemiological studies indicate that sex differences, as well as genetic components and ageing, can influence the prevalence, age at onset and symptomatology of PD. This study undertook a systematic meta-analysis of substantia nigra microarray data using the Transcriptome Mapper (TRAM) software to integrate and normalize a total of 10 suitable datasets from multiple sources. Four different analyses were performed according to default parameters, to better define the segments differentially expressed between PD patients and healthy controls, when comparing men and women data sets. The results suggest a possible regulation of specific sex-biased systems in PD susceptibility. TRAM software allowed us to highlight the different activation of some genomic regions and loci involved in molecular pathways related to neurodegeneration and neuroinflammatory mechanisms.

Meta-Analysis of Parkinson's Disease Transcriptome Data Using TRAM Software: Whole Substantia Nigra Tissue and Single Dopamine Neuron Differential Gene Expression.

The understanding of the genetic basis of the Parkinson's disease (PD) and the correlation between genotype and phenotype has revolutionized our knowledge about the pathogenetic mechanisms of neurodegeneration, opening up exciting new therapeutic and neuroprotective perspectives. Genomic knowledge of PD is still in its early stages and can provide a good start for studies of the molecular mechanisms that underlie the gene expression variations and the epigenetic mechanisms that may contribute to the complex and characteristic phenotype of PD. In this study we used the software TRAM (Transcriptome Mapper) to analyse publicly available microarray data of a total of 151 PD patients and 130 healthy controls substantia nigra (SN) samples, to identify chromosomal segments and gene loci differential expression. In particular, we separately analyzed PD patients and controls data from post-mortem snap-frozen SN whole tissue and from laser microdissected midbrain dopamine (DA) neurons, to better characterize the specific DA neuronal expression profile associated with the late-stage Parkinson's condition. The default "Map" mode analysis resulted in 10 significantly over/under-expressed segments, mapping on 8 different chromosomes for SN whole tissue and in 4 segments mapping on 4 different chromosomes for DA neurons. In conclusion, TRAM software allowed us to confirm the deregulation of some genomic regions and loci involved in key molecular pathways related to neurodegeneration, as well as to provide new insights about genes and non-coding RNA transcripts not yet associated with the disease.

Characterization of human gene locus CYYR1: a complex multi-transcript system.

Cysteine/tyrosine-rich 1 (CYYR1) is a gene we previously identified on human chromosome 21 starting from an in-depth bioinformatics analysis of chromosome 21 segment 40/105 (21q21.3), where no coding region had previously been predicted. CYYR1 was initially characterized as a four-exon gene, whose brain-derived cDNA sequencing predicts a 154-amino acid product. In this study we provide, with in silico and in vitro analyses, the first detailed description of the human CYYR1 locus. The analysis of this locus revealed that it is composed of a multi-transcript system, which includes at least seven CYYR1 alternative spliced isoforms and a new CYYR1 antisense gene (named CYYR1-AS1). In particular, we cloned, for the first time, the following isoforms: CYYR1-1,2,3,4b and CYYR1-1,2,3b, which present a different 3' transcribed region, with a consequent different carboxy-terminus of the predicted proteins; CYYR1-1,2,4 lacks exon 3; CYYR1-1,2,2bis,3,4 presents an additional exon between exon 2 and exon 3; CYYR1-1b,2,3,4 presents a different 5' untranslated region when compared to CYYR1. The complexity of the locus is enriched by the presence of an antisense transcript. We have cloned a long transcript overlapping with CYYR1 as an antisense RNA, probably a non-coding RNA. Expression analysis performed in different normal tissues, tumour cell lines as well as in trisomy 21 and euploid fibroblasts has confirmed a quantitative and qualitative variability in the expression pattern of the multi-transcript locus, suggesting a possible role in complex diseases that should be further investigated.

Parallel evolution of chordate cis-regulatory code for development.

Urochordates are the closest relatives of vertebrates and at the larval stage, possess a characteristic bilateral chordate body plan. In vertebrates, the genes that orchestrate embryonic patterning are in part regulated by highly conserved non-coding elements (CNEs), yet these elements have not been identified in urochordate genomes. Consequently the evolution of the cis-regulatory code for urochordate development remains largely uncharacterised. Here, we use genome-wide comparisons between C. intestinalis and C. savignyi to identify putative urochordate cis-regulatory sequences. Ciona conserved non-coding elements (ciCNEs) are associated with largely the same key regulatory genes as vertebrate CNEs. Furthermore, some of the tested ciCNEs are able to activate reporter gene expression in both zebrafish and Ciona embryos, in a pattern that at least partially overlaps that of the gene they associate with, despite the absence of sequence identity. We also show that the ability of a ciCNE to up-regulate gene expression in vertebrate embryos can in some cases be localised to short sub-sequences, suggesting that functional cross-talk may be defined by small regions of ancestral regulatory logic, although functional sub-sequences may also be dispersed across the whole element. We conclude that the structure and organisation of cis-regulatory modules is very different between vertebrates and urochordates, reflecting their separate evolutionary histories. However, functional cross-talk still exists because the same repertoire of transcription factors has likely guided their parallel evolution, exploiting similar sets of binding sites but in different combinations.

An estimation of the number of cells in the human body.

BACKGROUND: All living organisms are made of individual and identifiable cells, whose number, together with their size and type, ultimately defines the structure and functions of an organism. While the total cell number of lower organisms is often known, it has not yet been defined in higher organisms. In particular, the reported total cell number of a human being ranges between 10(12) and 10(16) and it is widely mentioned without a proper reference. AIM: To study and discuss the theoretical issue of the total number of cells that compose the standard human adult organism. SUBJECTS AND METHODS: A systematic calculation of the total cell number of the whole human body and of the single organs was carried out using bibliographical and/or mathematical approaches. RESULTS: A current estimation of human total cell number calculated for a variety of organs and cell types is presented. These partial data correspond to a total number of 3.72 × 10(13). CONCLUSIONS: Knowing the total cell number of the human body as well as of individual organs is important from a cultural, biological, medical and comparative modelling point of view. The presented cell count could be a starting point for a common effort to complete the total calculation.

Genome-scale analysis of human mRNA 5' coding sequences based on expressed sequence tag (EST) database.

The "5' end mRNA artifact" issue refers to the incorrect assignment of the first AUG codon in an mRNA, due to the incomplete determination of its 5' end sequence. We performed a systematic identification of coding regions at the 5' end of all human known mRNAs, using an automated expressed sequence tag (EST)-based approach. Following parsing of more than 7 million BLAT alignments, we found 477 human loci, out of 18,665 analyzed, in which an extension of the mRNA 5' coding region was identified. Proof-of-concept confirmation was obtained by in vitro cloning and sequencing for GNB2L1, QARS and TDP2 cDNAs, and the consequences for the functional studies of these loci are discussed. We also generated a list of 20,775 human mRNAs where the presence of an in-frame stop codon upstream of the known start codon indicates completeness of the coding sequence at 5' in the current form.

Complexity of bidirectional transcription and alternative splicing at human RCAN3 locus.

Human RCAN3 (regulator of calcineurin 3) belongs to the human RCAN gene family.In this study we provide, with in silico and in vitro analyses, the first detailed description of the human multi-transcript RCAN3 locus. Its analysis revealed that it is composed of a multigene system that includes at least 21 RCAN3 alternative spliced isoforms (16 of them identified here for the first time) and a new RCAN3 antisense gene (RCAN3AS). In particular, we cloned RCAN3-1,3,4,5 (lacking exon 2), RCAN3-1a,2,3,4,5, RCAN3-1a,3,4,5, RCAN3-1b,2,3,4,5, RCAN3-1c,2,3,4,5, RCAN3-1c,2,4,5 and RCAN3-1c,3,4,5, isoforms that present a different 5' untranslated region when compared to RCAN3. Moreover, in order to verify the possible 5' incompleteness of previously identified cDNA isoforms with the reference exon 1, ten more alternative isoforms were retrieved. Bioinformatic searches allowed us to identify RCAN3AS, which overlaps in part with exon 1a, on the opposite strand, for which four different RCAN3AS isoforms were cloned.In order to analyze the different expression patterns of RCAN3 alternative first exons and of RCAN3AS mRNA isoforms, RT-PCR was performed in 17 human tissues. Finally, analyses of RCAN3 and RCAN3AS genomic sequences were performed to identify possible promoter regions, to examine donor and acceptor splice sequences and to compare evolutionary conservation, in particular of alternative exon 1 or 1c--exon 2 junctions in different species.The description of its number of transcripts, of their expression patterns and of their regulatory regions can be important to clarify the functions of RCAN3 gene in different pathways and cellular processes.

TRAM (Transcriptome Mapper): database-driven creation and analysis of transcriptome maps from multiple sources.

BACKGROUND: Several tools have been developed to perform global gene expression profile data analysis, to search for specific chromosomal regions whose features meet defined criteria as well as to study neighbouring gene expression. However, most of these tools are tailored for a specific use in a particular context (e.g. they are species-specific, or limited to a particular data format) and they typically accept only gene lists as input. RESULTS: TRAM (Transcriptome Mapper) is a new general tool that allows the simple generation and analysis of quantitative transcriptome maps, starting from any source listing gene expression values for a given gene set (e.g. expression microarrays), implemented as a relational database. It includes a parser able to assign univocal and updated gene symbols to gene identifiers from different data sources. Moreover, TRAM is able to perform intra-sample and inter-sample data normalization, including an original variant of quantile normalization (scaled quantile), useful to normalize data from platforms with highly different numbers of investigated genes. When in 'Map' mode, the software generates a quantitative representation of the transcriptome of a sample (or of a pool of samples) and identifies if segments of defined lengths are over/under-expressed compared to the desired threshold. When in 'Cluster' mode, the software searches for a set of over/under-expressed consecutive genes. Statistical significance for all results is calculated with respect to genes localized on the same chromosome or to all genome genes. Transcriptome maps, showing differential expression between two sample groups, relative to two different biological conditions, may be easily generated. We present the results of a biological model test, based on a meta-analysis comparison between a sample pool of human CD34+ hematopoietic progenitor cells and a sample pool of megakaryocytic cells. Biologically relevant chromosomal segments and gene clusters with differential expression during the differentiation toward megakaryocyte were identified. CONCLUSIONS: TRAM is designed to create, and statistically analyze, quantitative transcriptome maps, based on gene expression data from multiple sources. The release includes FileMaker Pro database management runtime application and it is freely available at http://apollo11.isto.unibo.it/software/, along with preconfigured implementations for mapping of human, mouse and zebrafish transcriptomes.

Identification of housekeeping genes suitable for gene expression analysis in the zebrafish.

Housekeeping (HK) genes are constitutively expressed in order to maintain cellular function. They produce the minimal essential transcripts necessary for normal cellular physiology. Wide range expression, stable expression level and high expression level are independent features of a single gene expression and are all desirable for the definition of an "ideal" HK. Recent studies have questioned the possible existence of "ideal" HK mRNAs, mainly because of the wide expression conditions variability. This would imply that for each investigated organism the suitability of a putative HK should be verified. We perform a systematic analysis to identify "optimal" HK genes in Danio rerio (zebrafish), to be used in expression analyses conducted on embryos/larvae at different developmental stages, as well as on differentiated adult tissues from single donors. The expression pattern of candidate genes, selected on the basis of the literature available and of ad hoc bioinformatics analysis, was assessed by quantitative relative RT-PCR in an RNA panel, including six different embryo/larvae developmental stages and six adult tissues. Statistical analysis was performed to identify genes with the lowest expression standard deviation in the studied panel. Our results showed that beta-actin 2 (bactin2) is the mRNA with the lowest variability of expression.

Identification and analysis of human RCAN3 (DSCR1L2) mRNA and protein isoforms.

Human RCAN3 (Regulator of calcineurin 3; previously known as DSCR1L2, Down syndrome critical region gene 1-like 2) is a five-exon gene mapped on chromosome 1 and belongs to the human RCAN gene family which also includes RCAN1 and RCAN2. The novel denomination RCAN for genes and proteins, instead of DSCR1L (Down syndrome critical region gene 1-like) has recently been widely discussed. The aim of the present work was to perform a multiple approach analysis of five RCAN3 mRNA and encoded protein isoforms, two of which have been identified for the first time in this research. The two new RCAN3 mRNA isoforms, RCAN3-2,4,5, which lacks exon 3, and RCAN3-2,3,5, which lacks exon 4, were identified during RCAN3 RT-PCR (reverse transcription-polymerase chain reaction) cloning, the product of which unexpectedly revealed the presence of five isoforms as opposed to the three previously known. In order to analyze the expression pattern of the five RCAN3 mRNA isoforms in seven different human tissues, a quantitative relative RT-PCR was performed: interestingly, all isoforms are present in all tissues investigated, with a statistically significant constant prevalence of RCAN3 isoform (the most complete, "reference" isoform). The RCAN3 locus expression level was comparable in all seven tissues analyzed, considering all isoforms, which indicates a ubiquitous expression of this human RCAN family member. To date two possible interactors have been described for this protein: human cardiac troponin I (TNNI3) and calcineurin. Here we report the interaction between the new RCAN3 variants and TNNI3, demonstrated by both yeast cotransformation and by the GST (glutathione-sepharose transferase) fusion protein assay, as was to be expected from the presence of exon 2 whose product has been seen to be sufficient for binding to TNNI3.