Common activities and predictive gene signature identified for genetic hypomorphs of TP53.

Missense mutations that inactivate p53 occur commonly in cancer, and germline mutations in TP53 cause Li Fraumeni syndrome, which is associated with early-onset cancer. In addition, there are over two hundred germline missense variants of p53 that remain uncharacterized. In some cases, these germline variants have been shown to encode lesser-functioning, or hypomorphic, p53 protein, and these alleles are associated with increased cancer risk in humans and mouse models. However, most hypomorphic p53 variants remain un- or mis-classified in clinical genetics databases. There thus exists a significant need to better understand the behavior of p53 hypomorphs and to develop a functional assay that can distinguish hypomorphs from wild-type p53 or benign variants. We report the surprising finding that two different African-centric genetic hypomorphs of p53 that occur in distinct functional domains of the protein share common activities. Specifically, the Pro47Ser variant, located in the transactivation domain, and the Tyr107His variant, located in the DNA binding domain, both share increased propensity to misfold into a conformation specific for mutant, misfolded p53. Additionally, cells and tissues containing these hypomorphic variants show increased NF-κB activity. We identify a common gene expression signature from unstressed lymphocyte cell lines that is shared between multiple germline hypomorphic variants of TP53, and which successfully distinguishes wild-type p53 and a benign variant from lesser-functioning hypomorphic p53 variants. Our findings will allow us to better understand the contribution of p53 hypomorphs to disease risk and should help better inform cancer risk in the carriers of p53 variants.

Evidence for miR-548c-5p regulation of FOXC2 transcription through a distal genomic target site in human podocytes.

Podocytes are highly differentiated epithelial cells outlining the glomerular vessels. FOXC2 is a transcription factor essential for inducing podocyte differentiation, development and maturation, and is considered to be the earliest podocyte marker. miRNA prediction analysis revealed a full-length target site for the primate-specific miR-548c-5p at a genomic region > 8 kb upstream of FOXC2. We hypothesised that the transcription rates of FOXC2 during podocyte differentiation might be tuned by miR-548c-5p through this target site. Experiments were performed with cultured human podocytes, transfected with luciferase reporter constructs bearing this target site region within an enhancer element of the native plasmid. The results confirmed a seed region-driven targeting potential by the miRNA, with mimics downregulating and inhibitors enhancing luciferase activity. Introducing mutations into the miRNA target seed region abolished the expected response. In cultured podocytes, FOXC2 mRNA and protein levels responded to miR-548c-5p abundance in a coordinated manner before and after induction of differentiation, with high statistical significance. Ago-ChIP experiments revealed occupancy of the miRNA target site by miRNA/RISC in undifferentiated cells and its release when differentiation is initiated, allowing its interaction with the gene's promoter region to amplify FOXC2 expression, as shown by chromosome conformation capture and qRT-PCR. Moreover, the expression pattern of FOXC2 during podocyte differentiation seems to be affected by miR-548c-5p, as removal of either endogenous or mimic miR-548c-5p results in increased FOXC2 protein levels and cells resembling those undergoing differentiation. Collectively, results indicate a well-orchestrated regulatory model of FOXC2 expression by a remote upstream target site for miR-548c-5p.

Correction to: Evidence that DNA repair genes, a family of tumor suppressor genes, are associated with evolution rate and size of genomes.

In the original publication of this article [1], the Figure 1 and Figure 2 were wrong. The Figure 1 "Heat map showing the quantity of DNA repair genes, from red to blue in ascending order, per species' genome (numbers at the top of the figure represent the species code that is found in Table 1). Each DNA repair gene pathway was analyzed separately in rows. Radiated species' genomes are richer in DNA repair genes. Analytical data can be found in Additional file 2: Table S2. M mammals, B&R birds and reptiles, BF bony fishes" should be the picture of Figure 2. The figure 2 "Linear regression analysis. The number of DNA repair genes is linearly related to genome size and protein number. As a negative control, we show that genome size is not linearly related with protein number" should be the picture of figure 1.

Evidence that DNA repair genes, a family of tumor suppressor genes, are associated with evolution rate and size of genomes.

Adaptive radiation and evolutionary stasis are characterized by very different evolution rates. The main aim of this study was to investigate if any genes have a special role to a high or low evolution rate. The availability of animal genomes permitted comparison of gene content of genomes of 24 vertebrate species that evolved through adaptive radiation (representing high evolutionary rate) and of 20 vertebrate species that are considered as living fossils (representing a slow evolutionary rate or evolutionary stasis). Mammals, birds, reptiles, and bony fishes were included in the analysis. Pathway analysis was performed for genes found to be specific in adaptive radiation or evolutionary stasis respectively. Pathway analysis revealed that DNA repair and cellular response to DNA damage are important (false discovery rate = 8.35 × 10-5; 7.15 × 10-6, respectively) for species evolved through adaptive radiation. This was confirmed by further genetic in silico analysis (p = 5.30 × 10-3). Nucleotide excision repair and base excision repair were the most significant pathways. Additionally, the number of DNA repair genes was found to be linearly related to the genome size and the protein number (proteome) of the 44 animals analyzed (p < 1.00 × 10-4), this being compatible with Drake's rule. This is the first study where radiated and living fossil species have been genetically compared. Evidence has been found that cancer-related genes have a special role in radiated species. Linear association of the number of DNA repair genes with the species genome size has also been revealed. These comparative genetics results can support the idea of punctuated equilibrium evolution.

A Comprehensive Review on the Genetic Regulation of Cisplatin-induced Nephrotoxicity.

Cisplatin (CDDP) is a well-known antineoplastic drug which has been extensively utilized over the last decades in the treatment of numerous kinds of tumors. However, CDDP induces a wide range of toxicities in a dose-dependent manner, among which nephrotoxicity is of particular importance. Still, the mechanism of CDDP-induced renal damage is not completely understood; moreover, the knowledge about the role of microRNAs (miRNAs) in the nephrotoxic response is still unknown. miRNAs are known to interact with the representative members of a diverse range of regulatory pathways (including postnatal development, proliferation, inflammation and fibrosis) and pathological conditions, including kidney diseases: polycystic kidney diseases (PKDs), diabetic nephropathy (DN), kidney cancer, and drug-induced kidney injury. In this review, we shed light on the following important aspects: (i) information on genes/proteins and their interactions with previously known pathways engaged with CDDP-induced nephrotoxicity, (ii) information on newly discovered biomarkers, especially, miRNAs for detecting CDDP-induced nephrotoxicity and (iii) information to improve our understanding on CDDP. This information will not only help the researchers belonging to nephrotoxicity field, but also supply an indisputable help for oncologists to better understand and manage the side effects induced by CDDP during cancer treatment. Moreover, we provide up-to-date information about different in vivo and in vitro models that have been utilized over the last decades to study CDDP-induced renal injury. Taken together, this review offers a comprehensive network on genes, miRNAs, pathways and animal models which will serve as a useful resource to understand the molecular mechanism of CDDP-induced nephrotoxicity.

Evidence for activation of the unfolded protein response in collagen IV nephropathies.

Thin-basement-membrane nephropathy (TBMN) and Alport syndrome (AS) are progressive collagen IV nephropathies caused by mutations in COL4A3/A4/A5 genes. These nephropathies invariably present with microscopic hematuria and frequently progress to proteinuria and CKD or ESRD during long-term follow-up. Nonetheless, the exact molecular mechanisms by which these mutations exert their deleterious effects on the glomerulus remain elusive. We hypothesized that defective trafficking of the COL4A3 chain causes a strong intracellular effect on the cell responsible for COL4A3 expression, the podocyte. To this end, we overexpressed normal and mutant COL4A3 chains (G1334E mutation) in human undifferentiated podocytes and tested their effects in various intracellular pathways using a microarray approach. COL4A3 overexpression in the podocyte caused chain retention in the endoplasmic reticulum (ER) that was associated with activation of unfolded protein response (UPR)-related markers of ER stress. Notably, the overexpression of normal or mutant COL4A3 chains differentially activated the UPR pathway. Similar results were observed in a novel knockin mouse carrying the Col4a3-G1332E mutation, which produced a phenotype consistent with AS, and in biopsy specimens from patients with TBMN carrying a heterozygous COL4A3-G1334E mutation. These results suggest that ER stress arising from defective localization of collagen IV chains in human podocytes contributes to the pathogenesis of TBMN and AS through activation of the UPR, a finding that may pave the way for novel therapeutic interventions for a variety of collagenopathies.

MicroRNA profiling of rats with ochratoxin A nephrotoxicity.

BACKGROUND: Nephrotoxicity is the most prominent one among the various toxicities of ochratoxin A (OTA). MicroRNAs (miRNAs) are small non-coding RNAs that have an impact on a wide range of biological processes by regulating gene expression at post-transcriptional level or protein systhesis level. The objective of this study is to analyze miRNA profiling in the kidneys of rats gavaged with OTA. RESULTS: To profile miRNAs in the kidneys of rats with OTA nephrotoxicity, high-throughput sequencing and bioinformatics approaches were applied to analyze the miRNAs in the kidney of rats following OTA treatment. A total of 409 known miRNAs and 8 novel miRNAs were identified in the kidney and the levels of the novel miRNAs were varied in response to different doses of OTA. Expression of miR-129, miR-130a, miR-130b, miR-141, miR-218b and miR-3588 were uniquely suppressed in mid dose but then elevated in high dose, with opposite expression to their target genes. The expression pattern was closely related with the "MAPK signaling pathway". Dicer1 and Drosha were significantly suppressed, indicating an impairment of miRNA biogenesis in response to OTA. CONCLUSIONS: The abrogation of miRNA maturation process suggests a new target of OTA toxicity. Moreover, the identification of the differentially expressed miRNAs provides us a molecular insight into the nephrtoxicity of OTA.

Cell state dependent effects of Bmal1 on melanoma immunity and tumorigenicity.

The circadian clock regulator Bmal1 modulates tumorigenesis, but its reported effects are inconsistent. Here, we show that Bmal1 has a context-dependent role in mouse melanoma tumor growth. Loss of Bmal1 in YUMM2.1 or B16-F10 melanoma cells eliminates clock function and diminishes hypoxic gene expression and tumorigenesis, which could be rescued by ectopic expression of HIF1α in YUMM2.1 cells. By contrast, over-expressed wild-type or a transcriptionally inactive mutant Bmal1 non-canonically sequester myosin heavy chain 9 (Myh9) to increase MRTF-SRF activity and AP-1 transcriptional signature, and shift YUMM2.1 cells from a Sox10high to a Sox9high immune resistant, mesenchymal cell state that is found in human melanomas. Our work describes a link between Bmal1, Myh9, mouse melanoma cell plasticity, and tumor immunity. This connection may underlie cancer therapeutic resistance and underpin the link between the circadian clock, MRTF-SRF and the cytoskeleton.

In-Silico Algorithms for the Screening of Possible microRNA Binding Sites and Their Interactions.

MicroRNAs (miRNAs) comprise a recently discovered class of small, non-coding RNA molecules of 21-25 nucleotides in length that regulate the gene expression by base-pairing with the transcripts of their targets i.e. protein-coding genes, leading to down-regulation or repression of the target genes. However, target gene activation has also been described. miRNAs are involved in diverse regulatory pathways, including control of developmental timing, apoptosis, cell proliferation, cell differentiation, modulation of immune response to macrophages, and organ development and are associated with many diseases, such as cancer. Computational prediction of miRNA targets is much more challenging in animals than in plants, because animal miRNAs often perform imperfect base-pairing with their target sites, unlike plant miRNAs which almost always bind their targets with near perfect complementarity. In the past years, a large number of target prediction programs and databases on experimentally validated information have been developed for animal miRNAs to fulfil the need of experimental scientists conducting miRNA research. In this review we first succinctly describe the prediction criteria (rules or principles) adapted by prediction algorithms to generate possible miRNA binding site interactions and introduce most relevant algorithms, and databases. We then summarize their applications with the help of some previously published studies. We further provide experimentally validated functional binding sites outside 3'-UTR region of target mRNAs and the resources which offer such predictions. Finally, the issue of experimental validation of miRNA binding sites will be briefly discussed.

Increased number of microRNA target sites in genes encoded in CNV regions. Evidence for an evolutionary genomic interaction.

MicroRNAs (miRNAs) and copy number variations (CNVs) are two newly discovered genetic elements that have revolutionized the field of molecular biology and genetics. By performing in silico whole genome analysis, we demonstrate that both the number of miRNAs that target genes found in CNV regions as well as the number of miRNA-binding sites are significantly higher than those of genes found in non-CNV regions. This suggests that miRNAs may have acted as equilibrators of gene expression during evolution in an attempt to regulate aberrant gene expression and to increase the tolerance to genome plasticity.

Functional Annotation of MicroRNAs Using Existing Resources.

MicroRNAs (miRNAs) are endogenous small noncoding RNAs that are involved in most biological signaling pathways, including the cell cycle, apoptosis, proliferation, immune response, metabolism as well as in biological processes including organ development and in human diseases like cancers. During the past two decades, high-throughput transcriptomic profiling using next generation sequencing and microarrays have been extensively utilized to identify differentially expressed miRNAs across different conditions and diseases. A natural extension of miRNA identification is to the process of functionally annotating known or predicted gene targets of those miRNAs and, by inference, revealing their potential influences on diverse biological pathways and functions. In this chapter, we provide a stepwise guideline on how to perform functional enrichment analyses on miRNAs of interest using publicly available resources such as miRWalk2.0.

Integrated microRNA-mRNA Expression Profiling Identifies Novel Targets and Networks Associated with Autism.

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder, with mutations in hundreds of genes contributing to its risk. Herein, we studied lymphoblastoid cell lines (LCLs) from children diagnosed with autistic disorder (n = 10) and controls (n = 7) using RNA and miRNA sequencing profiles. The sequencing analysis identified 1700 genes and 102 miRNAs differentially expressed between the ASD and control LCLs (p ≤ 0.05). The top upregulated genes were GABRA4, AUTS2, and IL27, and the top upregulated miRNAs were hsa-miR-6813-3p, hsa-miR-221-5p, and hsa-miR-21-5p. The RT-qPCR analysis confirmed the sequencing results for randomly selected candidates: AUTS2, FMR1, PTEN, hsa-miR-15a-5p, hsa-miR-92a-3p, and hsa-miR-125b-5p. The functional enrichment analysis showed pathways involved in ASD control proliferation of neuronal cells, cell death of immune cells, epilepsy or neurodevelopmental disorders, WNT and PTEN signaling, apoptosis, and cancer. The integration of mRNA and miRNA sequencing profiles by miRWalk2.0 identified correlated changes in miRNAs and their targets' expression. The integration analysis found significantly dysregulated miRNA-gene pairs in ASD. Overall, these findings suggest that mRNA and miRNA expression profiles in ASD are greatly altered in LCLs and reveal numerous miRNA-gene interactions that regulate critical pathways involved in the proliferation of neuronal cells, cell death of immune cells, and neuronal development.

A bovine miRNA, bta-miR-154c, withstands in vitro human digestion but does not affect cell viability of colorectal human cell lines after transfection.

Colorectal cancer (CRC) is the third most frequent human cancer with over 1.3 million new cases globally. CRC is a complex disease caused by interactions between genetic and environmental factors; in particular, high consumption of red meat, including beef, is considered a risk factor for CRC initiation and progression. Recent data demonstrate that exogenous microRNAs (miRNAs) entering the body via ingestion could pose an effect on the consumer. In this study, we focused on bovine miRNAs that do not share a seed sequence with humans and mice. We identified bta-miR-154c, a bovine miRNA found in edible parts of beef and predicted via cross-species bioinformatic analysis to affect cancer-related pathways in human cells. When bovine tissue was subjected to cooking and a simulation of human digestion, bta-miR-154c was still detected after all procedures, albeit at reduced concentrations. However, lipofection of bta-miR-154c in three different colorectal human cell lines did not affect their viability as evaluated at various time points and concentrations. These data indicate that bta-miR-154c (a) may affect cancer-related pathways in human cells, (b) can withstand digestion and be detected after all stages of an in vitro digestion protocol, but (c) it does not appear to alter epithelial cell viability after entering human enterocytes, even at supraphysiological amounts. Further experiments will elucidate whether bta-miR-154c exerts a different functional effect on the human gut epithelium, which may cause it to contribute to CRC progression through its consumption.

miRWalk--database: prediction of possible miRNA binding sites by "walking" the genes of three genomes.

MicroRNAs are small, non-coding RNA molecules that can complementarily bind to the mRNA 3'-UTR region to regulate the gene expression by transcriptional repression or induction of mRNA degradation. Increasing evidence suggests a new mechanism by which miRNAs may regulate target gene expression by binding in promoter and amino acid coding regions. Most of the existing databases on miRNAs are restricted to mRNA 3'-UTR region. To address this issue, we present miRWalk, a comprehensive database on miRNAs, which hosts predicted as well as validated miRNA binding sites, information on all known genes of human, mouse and rat. All mRNAs, mitochondrial genes and 10 kb upstream flanking regions of all known genes of human, mouse and rat were analyzed by using a newly developed algorithm named 'miRWalk' as well as with eight already established programs for putative miRNA binding sites. An automated and extensive text-mining search was performed on PubMed database to extract validated information on miRNAs. Combined information was put into a MySQL database. miRWalk presents predicted and validated information on miRNA-target interaction. Such a resource enables researchers to validate new targets of miRNA not only on 3'-UTR, but also on the other regions of all known genes. The 'Validated Target module' is updated every month and the 'Predicted Target module' is updated every 6 months. miRWalk is freely available at http://mirwalk.uni-hd.de/.

Molecular Dysregulation in Autism Spectrum Disorder.

Autism Spectrum Disorder (ASD) comprises a heterogeneous group of neurodevelopmental disorders with a strong heritable genetic component. At present, ASD is diagnosed solely by behavioral criteria. Advances in genomic analysis have contributed to numerous candidate genes for the risk of ASD, where rare mutations and s common variants contribute to its susceptibility. Moreover, studies show rare de novo variants, copy number variation and single nucleotide polymorphisms (SNPs) also impact neurodevelopment signaling. Exploration of rare and common variants involved in common dysregulated pathways can provide new diagnostic and therapeutic strategies for ASD. Contributions of current innovative molecular strategies to understand etiology of ASD will be explored which are focused on whole exome sequencing (WES), whole genome sequencing (WGS), microRNA, long non-coding RNAs and CRISPR/Cas9 models. Some promising areas of pharmacogenomic and endophenotype directed therapies as novel personalized treatment and prevention will be discussed.

MicroRNA Expression Profiles in Autism Spectrum Disorder: Role for miR-181 in Immunomodulation.

BACKGROUND: MicroRNAs (miRNAs) are important regulators of molecular pathways in psychiatric disease. Here, we examine differential miRNAs expression in lymphoblastoid cell lines (LCLs) derived from 10 individuals with autism spectrum disorder (ASD) and compare them to seven typically developing unrelated age- and gender-matched controls and 10 typically developing siblings. Small RNAseq analysis identified miRNAs, and selected miRNAs were validated using quantitative real-time polymerase reaction (qRT-PCR). KEGG analysis identified target pathways, and selected predicted mRNAs were validated using qRT-PCR. RESULTS: Small RNAseq analysis identified that multiple miRNAs differentiated ASD from unrelated controls and ASD from typically developing siblings, with only one, hsa-miR-451a_R-1, being in common. Verification with qRT-PCR showed that miR-320a differentiated ASD from both sibling and unrelated controls and that several members of the miR-181 family differentiated ASD from unrelated controls. Differential expression of AKT2, AKT3, TNF α and CamKinase II predicted by KEGG analysis was verified by qRT-PCR. Expression of CamKinase II ßwas found to be correlated with the severity of stereotyped behavior of the ASD participants. CONCLUSIONS: This study provides insight into the mechanisms regulating molecular pathways in individuals with ASD and identifies differentiated regulated genes involved in both the central nervous system and the immune system.

Corrigendum: Plasma Markers of Disrupted Gut Permeability in Severe COVID-19 Patients.

[This corrects the article DOI: 10.3389/fimmu.2021.686240.].

Plasma Markers of Disrupted Gut Permeability in Severe COVID-19 Patients.

A disruption of the crosstalk between the gut and the lung has been implicated as a driver of severity during respiratory-related diseases. Lung injury causes systemic inflammation, which disrupts gut barrier integrity, increasing the permeability to gut microbes and their products. This exacerbates inflammation, resulting in positive feedback. We aimed to test whether severe Coronavirus disease 2019 (COVID-19) is associated with markers of disrupted gut permeability. We applied a multi-omic systems biology approach to analyze plasma samples from COVID-19 patients with varying disease severity and SARS-CoV-2 negative controls. We investigated the potential links between plasma markers of gut barrier integrity, microbial translocation, systemic inflammation, metabolome, lipidome, and glycome, and COVID-19 severity. We found that severe COVID-19 is associated with high levels of markers of tight junction permeability and translocation of bacterial and fungal products into the blood. These markers of disrupted intestinal barrier integrity and microbial translocation correlate strongly with higher levels of markers of systemic inflammation and immune activation, lower levels of markers of intestinal function, disrupted plasma metabolome and glycome, and higher mortality rate. Our study highlights an underappreciated factor with significant clinical implications, disruption in gut functions, as a potential force that may contribute to COVID-19 severity.

COVID-19 Severity Is Associated with Differential Antibody Fc-Mediated Innate Immune Functions.

Beyond neutralization, antibodies binding to their Fc receptors elicit several innate immune functions including antibody-dependent complement deposition (ADCD), antibody-dependent cell-mediated phagocytosis (ADCP), and antibody-dependent cell-mediated cytotoxicity (ADCC). These functions are beneficial, as they contribute to pathogen clearance; however, they also can induce inflammation. We tested the possibility that qualitative differences in SARS-CoV-2-specific antibody-mediated innate immune functions contribute to coronavirus disease 2019 (COVID-19) severity. We found that anti-S1 and anti-RBD antibodies from hospitalized COVID-19 patients elicited higher ADCD but lower ADCP compared to antibodies from nonhospitalized COVID-19 patients. Consistently, higher ADCD was associated with higher systemic inflammation, whereas higher ADCP was associated with lower systemic inflammation during COVID-19. Our study points to qualitative, differential features of anti-SARS-CoV-2 specific antibodies as potential contributors to COVID-19 severity. Understanding these qualitative features of natural and vaccine-induced antibodies will be important in achieving optimal efficacy and safety of SARS-CoV-2 vaccines and/or COVID-19 therapeutics.IMPORTANCE A state of hyperinflammation and increased complement activation has been associated with coronavirus disease 2019 (COVID-19) severity. However, the pathophysiological mechanisms that contribute to this phenomenon remain mostly unknown. Our data point to a qualitative, rather than quantitative, difference in SARS-CoV-2-specific antibodies' ability to elicit Fc-mediated innate immune functions as a potential contributor to COVID-19 severity and associated inflammation. These data highlight the need for further studies to understand these qualitative features and their potential contribution to COVID-19 severity. This understanding could be essential to develop antibody-based COVID-19 therapeutics and SARS-CoV-2 vaccines with an optimal balance between efficacy and safety.