Human Gene Research Articles

AAV-NRIP gene therapy ameliorates motor neuron degeneration and muscle atrophy in ALS model mice

BackgroundAmyotrophic lateral sclerosis (ALS) is characterized by progressive motor neuron (MN) degeneration, leading to neuromuscular junction (NMJ) dismantling and severe muscle atrophy. The nuclear receptor interaction protein (NRIP) functions as a multifunctional protein. It directly interacts with calmodulin or α-actinin 2, serving as a calcium sensor for muscle contraction and maintaining sarcomere integrity. Additionally, NRIP binds with the acetylcholine receptor (AChR) for NMJ stabilization. Loss of NRIP in muscles results in progressive motor neuron degeneration with abnormal NMJ architecture, resembling ALS phenotypes. Therefore, we hypothesize that NRIP could be a therapeutic factor for ALS.MethodsWe used SOD1 G93A mice, expressing human SOD1 with the ALS-linked G93A mutation, as an ALS model. An adeno-associated virus vector encoding the human NRIP gene (AAV-NRIP) was generated and injected into the muscles of SOD1 G93A mice at 60 days of age, before disease onset. Pathological and behavioral changes were measured to evaluate the therapeutic effects of AAV-NRIP on the disease progression of SOD1 G93A mice.ResultsSOD1 G93A mice exhibited lower NRIP expression than wild-type mice in both the spinal cord and skeletal muscle tissues. Forced NRIP expression through AAV-NRIP intramuscular injection was observed in skeletal muscles and retrogradely transduced into the spinal cord. AAV-NRIP gene therapy enhanced movement distance and rearing frequencies in SOD1 G93A mice. Moreover, AAV-NRIP increased myofiber size and slow myosin expression, ameliorated NMJ degeneration and axon terminal denervation at NMJ, and increased the number of α-motor neurons (α-MNs) and compound muscle action potential (CMAP) in SOD1 G93A mice.ConclusionsAAV-NRIP gene therapy ameliorates muscle atrophy, motor neuron degeneration, and axon terminal denervation at NMJ, leading to increased NMJ transmission and improved motor functions in SOD1 G93A mice. Collectively, AAV-NRIP could be a potential therapeutic drug for ALS.

ZDB: bacterial comparative genomics made easy.

The analysis and comparison of genomes rely on different tools for tasks such as annotation, orthology prediction, and phylogenetic inference. Most tools are specialized for a single task, and additional efforts are necessary to integrate and visualize the results. To fill this gap, we developed zDB, an application integrating a Nextflow analysis pipeline and a Python visualization platform built on the Django framework. The application is available on GitHub (https://github.com/metagenlab/zDB) and from the bioconda channel. Starting from annotated Genbank files, zDB identifies orthologs and infers a phylogeny for each orthogroup. A species phylogeny is also constructed from shared single-copy orthologs. The results can be enriched with Pfam protein domain prediction, Cluster of Orthologs Genes and Kyoto Encyclopedia of Genes and Genomes annotations, and Swissprot homologs. The web application allows searching for specific genes or annotations, running Blast queries, and comparing genomic regions and whole genomes. The metabolic capacities of organisms can be compared at either the module or pathway levels. Finally, users can run queries to examine the conservation of specific genes or annotations across a chosen subset of genomes and display the results as a list of genes, Venn diagram, or heatmaps. Those features make zDB useful for both bioinformaticians and researchers more accustomed to laboratory research.IMPORTANCEGenome comparison and analysis rely on many independent tools, leaving to scientists the burden to integrate and visualize their results for interpretation. To alleviate this burden, we have built zDB, a comparative genomics tool that includes both an analysis pipeline and a visualization platform. The analysis pipeline automates gene annotation, orthology prediction, and phylogenetic inference, while the visualization platform allows scientists to easily explore the results in a web browser. Among other features, the interface allows users to visually compare whole genomes and targeted regions, assess the conservation of genes or metabolic pathways, perform Blast searches, or look for specific annotations. Altogether, this tool will be useful for a broad range of applications in comparative studies between two and hundred genomes. Furthermore, it is designed to allow sharing of data sets easily at a local or international scale, thereby supporting exploratory analyses for non-bioinformaticians on the genome of their favorite organisms.

Transcriptomic analyses of differentially expressed human genes, micro RNAs and long-non-coding RNAs in severe, symptomatic and asymptomatic malaria infection

Malaria transmission and endemicity in Africa remains hugely disproportionate compared to the rest of the world. The complex life cycle of P. falciparum (Pf) between the vertebrate human host and the anopheline vector results in differential expression of genes within and between hosts. An in-depth understanding of Pf interaction with various human genes through regulatory elements will pave way for identification of newer tools in the arsenal for malaria control. Therefore, the regulatory elements (REs) involved in the over- or under-expression of various host immune genes hold the key to elucidating alternative control measures that can be applied for disease surveillance, prompt diagnosis and treatment. We carried out an RNAseq analysis to identify differentially expressed genes and network elucidation of non-coding RNAs and target genes associated with immune response in individuals with different clinical outcomes. Raw RNAseq datasets, retrieved for analyses include individuals with severe (Gambia—20), symptomatic (Burkina Faso—15), asymptomatic (Mali—16) malaria as well as uninfected controls (Tanzania—20; Mali—36). Of the total 107 datasets retrieved, we identified 5534 differentially expressed genes (DEGs) among disease and control groups. A peculiar pattern of DEGs was observed, with individuals presenting with severe/symptomatic malaria having the highest and most diverse upregulated genes, while a reverse phenomenon was recorded among asymptomatic and uninfected individuals. In addition, we identified 141 differentially expressed micro RNA (miRNA), of which 78 and 63 were upregulated and downregulated respectively. Interactome analysis revealed a moderate interaction between DEGs and miRNAs. Of all identified miRNA, five were unique (hsa-mir-32, hsa-mir-25, hsa-mir-221, hsa-mir-29 and hsa-mir-148) because of their connectivity to several genes, including hsa-mir-221 connected to 16 genes. Six-hundred and eight differentially expressed long non coding RNA (lncRNA) were also identified, including SLC7A11, LINC01524 among the upregulated ones. Our study provides important insight into host immune genes undergoing differential expression under different malaria conditions. It also identified unique miRNAs and lncRNAs that modify and/or regulate the expression of various immune genes. These regulatory elements we surmise, have the potential to serve a diagnostic purpose in discriminating between individuals with severe/symptomatic malaria and those with asymptomatic infection or uninfected, following further clinical validation from field isolates.

A new mutation of Sgms1 causes gradual hearing loss associated with a reduced endocochlear potential

Sgms1 encodes sphingomyelin synthase 1, an enzyme in the sphingosine-1-phosphate signalling pathway, and was previously reported to underlie hearing impairment in the mouse. A new mouse allele, Sgms1tm1a, unexpectedly showed normal Auditory Brainstem Response thresholds. We found that the Sgms1tm1a mutation led to incomplete knockdown of transcript to 20% of normal values, which was enough to support normal hearing. The Sgms1tm1b allele was generated by knocking out exon 7, leading to a complete lack of detectable transcript in the inner ear. Sgms1tm1b homozygotes showed largely normal auditory brainstem response thresholds at first, followed by progressive loss of sensitivity until they showed severe impairment at 6 months old. The endocochlear potential was consistently reduced in Sgms1tm1b mutants at 3, 4 and 8 weeks old, to around 80mV compared with around 120mV in control littermates. The stria vascularis showed a characteristic irregularity of marginal cell surfaces and patchy loss of Kcnq1 expression at their apical membrane, and expression analysis of the lateral wall suggested that marginal cells were the most likely initial site of dysfunction in the mutants. Finally, significant association of auditory thresholds with DNA markers within and close to the human SGMS1 gene were found in the 1958 Birth Cohort, suggesting that SGMS1 variants may play a role in the range of hearing abilities in the human population.

Generation and preclinical evaluation of a human heavy-chain-only antibody recognizing the membrane-bound tumor-associated antigen mesothelin

ObjectiveMesothelin (MSLN) is an attractive target for anticancer therapeutics and bioimaging reagents that utilize antibodies. This study was aimed at developing a novel human anti-MSLN single-domain antibody that exclusively binds to the membrane-attached MSLN using transgenic mice generating human heavy-chain-only antibodies (HCAbs) and exploring the resulting HCAbs as imaging tools.MethodsWe introduced a doxycycline-inducible human MSLN gene in genetically modified mice expressing human HCAbs. This new method of non-invasive immunization by antigen induction results in MSLN antigen production in its native conformation on the cell surface. Screening of 2,000 HCAbs from the resulting immune library yielded numerous binders, from which we chose 19G6 as the lead antibody. This antibody was 111Indium radiolabeled and tested in a xenotransplantation tumor model with OVCAR-3 cells.ResultsThe 19G6 antibody shows nanomolar affinity toward membrane-bound MSLN and does not recognize soluble MSLN. The human MSLN-positive tumors were visualized in an in vivo mouse model. The non-labeled antibody prevented binding when provided in excess, showing tumor specificity.Conclusion19G6 with a human Fc is a promising tumor-cell tracer in vivo. This HCAb can also be engineered into a smaller and shorter-lived tracer (only the VH domain) or combined with other target-binding domains to form multispecific modalities for tumor immunotherapy.

Transcriptome analysis of the molecular basis of 11‐eicosenoic acid‐mediated salt stress tolerance in rice

AbstractSalt stress is one of the major abiotic factors severely hampering rice production. Fatty acids play a crucial role in plants response to such stress. Previous studies have demonstrated the potential of unsaturated fatty acid (11‐eicosenoic acid [EA]) to enhance salt tolerance in rice, but the molecular mechanism remains unclear. Our study indicates that the exogenous application of EA could alleviate salt stress‐induced damage as well as improve the survival rate of rice seedlings. Transcriptome analysis was performed following treatment of rice seedlings with EA, NaCl, and NaCl + EA. The results showed that there were 4970, 11, 304, and 4735 differentially expressed genes (DEGs) in NaCl versus CK, EA versus CK, NaCl + EA versus NaCl, and NaCl + EA versus CK, respectively. Notably, pathways such as unsaturated fatty acid metabolism, diterpenoid phytoalexin biosynthesis, and phytohormone signal transduction were significantly enriched in NaCl + EA versus NaCl. Specifically, genes related to ethylene, abscisic acid, jasmonic acid, salicylic acid, gibberellin signaling, and fatty acid metabolism were implicated in the mitigation effect of EA on salt stress in rice. Furthermore, DEGs involved in rice diterpenoid biosynthesis were analyzed in detail, revealing that EA induced the biosynthesis of multiple diterpenoids. Metabolomic analysis showed that the levels of various fatty acids, phytohormones, and terpenes increased. The presented data may serve as a useful guide for further exploration of the various biological functions of EA in enhancing plant resilience to salt stress. Additionally, it offers a valuable list of genes for the development of crop plants with improved salt resistance.

Dengue virus preferentially uses human and mosquito non-optimal codons.

Codon optimality refers to the effect that codon composition has on messenger RNA (mRNA) stability and translation level and implies that synonymous codons are not silent from a regulatory point of view. Here, we investigated the adaptation of virus genomes to the host optimality code using mosquito-borne dengue virus (DENV) as a model. We demonstrated that codon optimality exists in mosquito cells and showed that DENV preferentially uses nonoptimal (destabilizing) codons and avoids codons that are defined as optimal (stabilizing) in either human or mosquito cells. Human genes enriched in the codons preferentially and frequently used by DENV are upregulated during infection, and so is the tRNA decoding the nonoptimal and DENV preferentially used codon for arginine. We found that adaptation during single-host passaging in human or mosquito cells results in the selection of synonymous mutations towards DENV's preferred nonoptimal codons that increase virus fitness. Finally, our analyses revealed that hundreds of viruses preferentially use nonoptimal codons, with those infecting a single host displaying an even stronger bias, suggesting that host-pathogen interaction shapes virus-synonymous codon choice.

Simplified Electrochemical Approach for End-Point Yet Quantitative Detection of Nucleic Acids in Resource-Limited Settings.

Nucleic acid detection plays a crucial role in various aspects of health care, necessitating accessible and reliable quantification methods, especially in resource-limited settings. This work presents a simplified electrochemical approach for end-point yet quantitative nucleic acid detection. By elevating the concentration of redox species and choosing potential as the signals, we achieved enhanced signal robustness, even in the presence of interfering substances. Leveraging this robustness, we accurately measured pH-induced redox potential changes in methylene blue solution for end-point nucleic acid detection after loop-mediated isothermal amplification (LAMP). Our method demonstrated quantitative detection of the SARS-CoV-2 N gene and human ATCB gene and successful discrimination of the human BRAF V600E mutation, comparable in sensitivity to commercial kits. The developed user-friendly electrochemical method offers a simplified and reliable approach for end-point yet quantitative detection of nucleic acids, potentially expanding the benefits of nucleic acid testing in resource-limited settings.

Increased expression of human endogenous retrovirus K in endomyocardial biopsies from patients with cardiomyopathy – a transcriptomics meta-analysis

Most studied, investigating transcriptional changes in myocardial biopsies focus on human genes. However, the presence and potential consequence of persistent expression of viral genes within the myocardium is unclear. The aim of the study was to analyze viral gene expression in RNAseq data from endomyocardial biopsies. The NCBI Bioproject library was screened for published projects that included bulk RNA sequencing data from endomyocardial biopsies from both healthy and diseased patients with a sample size greater than 20. Diseased patients with hypertrophic, dilated, and ischemic cardiomyopathies were included. A total of 507 patients with 507 samples from 6 bioprojects were included and mapped to the human genome (hg38). Unmappable sequences were extracted and mapped to an artificial ‘super-virus’ genome comprising 12,182 curated viral reference genomes. Subsequently, the sequences were reiteratively permutated and mapped again to account for randomness. In total, sequences from 68 distinct viruses were found, all of which were potentially human pathogenic. No increase in cardiotropic viruses was found in patients with dilated cardiomyopathy. However, the expression levels of the particle forming human endogenous retrovirus K were significantly increased (q < 0.0003, ANOVA). Higher expression levels were associated with increased expression in mitochondrial pathways such as oxidative phosphorylation (p < 0.0001). In Conclusion, expression of human endogenous retrovirus K is significantly increased in patients with dilated cardiomyopathy, which in turn was associated with transcriptional alterations in major cellular pathways.

Role of palmitoylation on the neuronal glycine transporter GlyT2.

The neuronal glycine transporter GlyT2 removes glycine from the synaptic cleft through active Na+, Cl-, and glycine cotransport contributing to the termination of the glycinergic signal as well as supplying substrate to the presynaptic terminal for the maintenance of the neurotransmitter content in synaptic vesicles. Patients with mutations in the human GlyT2 gene (SLC6A5), develop hyperekplexia or startle disease (OMIM 149400), characterized by hypertonia and exaggerated startle responses to trivial stimuli that may have lethal consequences in the neonates as a result of apnea episodes. Post-translational modifications in cysteine residues of GlyT2 are an aspect of structural interest we analyzed. Our study is compatible with a reversible and short-lived S-acylation in spinal cord membranes, detectable by biochemical and proteomics methods (acyl-Rac binding and IP-ABE) confirmed with positive and negative controls (palmitoylated and non-palmitoylated proteins). According to a short-lived modification, direct labeling using click chemistry was faint but mostly consistent. We have analyzed the physiological properties of a GlyT2 mutant lacking the cysteines with high prediction of palmitoylation and the mutant is less prone to be included in lipid rafts, an effect also observed upon treatment with the palmitoylation inhibitor 2-bromopalmitate. This work demonstrates there are determinants of lipid raft inclusion associated with the GlyT2 mutated cysteines, which are presumably modified by palmitoylation.

Transcriptomic response to pyrethroid treatment in closely related bed bug strains varying in resistance.

The common bed bug, Cimex lectularius, is one of the main human parasites. The world-wide resurgence of this pest is mainly due to globalization, and the spread of insecticide resistance. A few studies have compared the transcriptomes of susceptible and resistant strains; however, these studies usually relied on strains originating from distant locations, possibly explaining their extended candidate gene lists. Here, we compared the transcriptomes of two strains originating from the same location and showing low overall genetic differentiation (FST=0.018) but varying in their susceptibility to pyrethroids, before and after insecticide exposure. In sharp contrast with previous studies, only 24 genes showing constitutive differential expression between the strains were identified. Interestingly, most of the genes with increased expression in the resistant strain encoded cuticular proteins. However, those changes were not associated with significant difference in cuticular thickness, suggesting that they might be involved in qualitative changes in the cuticle. In contrast, insecticide exposure induced the expression of a multitude of genes, mostly involved in detoxification. Finally, our set of transcriptome candidate loci showed little overlap with a set of loci strongly genetically differentiated in a previous study using the same strains. Several hypothesis explaining this discrepancy are discussed.

Building, Maintaining, and (re-)Deploying Genetic Toolkits during Convergent Evolution.

A surprising insight from the advent of genomic sequencing was that many genes are deeply conserved during evolution. With a particular focus on genes that interact with light in animals, I explore the metaphor of genetic toolkits, which can be operationalized as lists of genes involved in a trait of interest. A fascinating observation is that genes of a toolkit are often used again and again during convergent evolution, sometimes across vast phylogenetic distances. Such a pattern in the evolution of toolkits requires three different stages: origin, maintenance, and redeployment of the genes. The functional origins of toolkit genes might often be rooted in interactions with external environments. The origins of light interacting genes in particular may be tied to ancient responses to photo-oxidative stress, inspiring questions about the extent to which the evolution of other toolkits were also impacted by stress. Maintenance of genetic toolkits over long evolutionary timescales requires gene multifunctionality to prevent gene loss when a trait of interest is absent. Finally, the deployment of toolkit genes in convergently evolved traits like eyes sometimes involves the repeated use of similar, ancient genes but other times involves different genes specific to each convergent origin. How often a particular gene family is used time and again for the same function may depend on how many possible biological solutions are available. When few solutions exist and are maintained, evolution is constrained to use the same genes over and over. However, when many different solutions are possible, the innovative possibilities of evolution are often on display. Therefore, a focus on genetic toolkits highlights the combination of legacy-plus-innovation that drives the evolution of biological diversity.

Current advance on distal myopathy genetics.

Distal myopathies are a clinically heterogenous group of rare, genetic muscle diseases, that present with weakness in hands and/or feet at onset. Some of these diseases remain accentuated in the distal muscles whereas others may later progress to the proximal muscles. In this review, the latest findings related to genetic and clinical features of distal myopathies are summarized. Variants in SMPX, DNAJB2, and HSPB6 have been identified as a novel cause of late-onset distal myopathy and neuromyopathy. In oculopharyngodistal myopathies, repeat expansions were identified in two novel disease-causing genes, RILPL1 and ABCD3. In multisystem proteinopathies, variants in HNRNPA1 and TARDBP, genes previously associated with amyotrophic lateral sclerosis, have been shown to cause late-onset distal myopathy without ALS. In ACTN2-related distal myopathy, the first recessive forms of the disease have been described, adding it to the growing list of genes were both dominant and recessive forms of myopathy are present. The identification of novel distal myopathy genes and pathogenic variants contribute to our ability to provide a final molecular diagnosis to a larger number of patients and increase our overall understanding of distal myopathy genetics and pathology.

Sources of gene expression variation in a globally diverse human cohort.

Genetic variation that influences gene expression and splicing is a key source of phenotypic diversity1-5. Although invaluable, studies investigating these links in humans have been strongly biased towards participants of European ancestries, which constrains generalizability and hinders evolutionary research. Here to address these limitations, we developed MAGE, an open-access RNA sequencing dataset of lymphoblastoid cell lines from 731 individuals from the 1000 Genomes Project6, spread across 5 continental groups and 26 populations. Most variation in gene expression (92%) and splicing (95%) was distributed within versus between populations, which mirrored the variation in DNA sequence. We mapped associations between genetic variants and expression and splicing of nearby genes (cis-expression quantitative trait loci (eQTLs) and cis-splicing QTLs (sQTLs), respectively). We identified more than 15,000 putatively causal eQTLs and more than 16,000 putatively causal sQTLs that are enriched for relevant epigenomic signatures. These include 1,310 eQTLs and 1,657 sQTLs that are largely private to underrepresented populations. Our data further indicate that the magnitude and direction of causal eQTL effects are highly consistent across populations. Moreover, the apparent 'population-specific' effects observed in previous studies were largely driven by low resolution or additional independent eQTLs of the same genes that were not detected. Together, our study expands our understanding of human gene expression diversity and provides an inclusive resource for studying the evolution and function of human genomes.

Molecular dissection of cobra venom highlights heparinoids as an antidote for spitting cobra envenoming.

Snakebites affect about 1.8 million people annually. The current standard of care involves antibody-based antivenoms, which can be difficult to access and are generally not effective against local tissue injury, the primary cause of morbidity. Here, we used a pooled whole-genome CRISPR knockout screen to define human genes that, when targeted, modify cell responses to spitting cobra venoms. A large portion of modifying genes that conferred resistance to venom cytotoxicity was found to control proteoglycan biosynthesis, including EXT1, B4GALT7, EXT2, EXTL3, XYLT2, NDST1, and SLC35B2, which we validated independently. This finding suggested heparinoids as possible inhibitors. Heparinoids prevented venom cytotoxicity through binding to three-finger cytotoxins, and the US Food and Drug Administration-approved heparinoid tinzaparin was found to reduce tissue damage in mice when given via a medically relevant route and dose. Overall, our systematic molecular dissection of cobra venom cytotoxicity provides insight into how we can better treat cobra snakebite envenoming.

Enhanced hippocampal TIAM2S expression alleviates cognitive deficits in Alzheimer's disease model mice.

Dendritic spine dysfunction is a key feature of Alzheimer's disease (AD) pathogenesis. Human T-cell lymphoma invasion and metastasis 2 (TIAM2) is expressed in two isoforms, the full length (TIAM2L) and a short transcript (TIAM2S). Compared to TIAM2L protein, which is undetectable, TIAM2S protein is abundant in human brain tissue, especially the hippocampus, and can promote neurite outgrowth in our previous findings. However, whether enhanced hippocampal TIAM2S expression can alleviate cognitive deficits in Alzheimer's disease model mice remains unclear. We crossbred 3xTg-AD with TIAM2S mice to generate an AD mouse model that carries the human TIAM2S gene (3xTg-AD/TIAM2S mice). The Morris water maze and object location tests assessed hippocampus-dependent spatial memory. Lentiviral-driven shRNA or cDNA approaches were used to manipulate hippocampal TIAM2S expression. Golgi staining and Sholl analysis were utilized to measure neuronal dendrites and dendritic spines in the mouse hippocampi. Compared to 3xTg-AD mice, 3xTg-AD/TIAM2S mice displayed improved cognitive functions. According to the hippocampus is one of the earliest affected brain regions by AD, we further injected TIAM2S shRNA or TIAM2S cDNA into mouse hippocampi to confirm whether manipulating hippocampal TIAM2S expression could affect AD-related cognitive functions. The results showed that the reduced hippocampal TIAM2S expression in 3xTg-AD/TIAM2S mice abolished the memory improvement effect, whereas increased hippocampal TIAM2S levels alleviated cognitive deficits in 3xTg-AD mice. Furthermore, we found that TIAM2S-mediated memory improvement was achieved by regulating dendritic plasticity. These results will provide new insights into connecting TIAM2S with AD and support the notion that TIAM2S should be investigated as potential AD therapeutic targets.

Major clinical and metabomic approaches to childhood obesity: a systematic review

Introduction: In the context of childhood obesity, of children under 5 years of age in Brazil, 7% are overweight and 3% meet the criteria for obesity. Globally, according to a report from the World Health Organization (WHO), it is estimated that the total number of overweight and obese children in the world could reach 75 million by the year 2025. Objective: It was to carry out a systematic review to present the main approaches to clinical and metabolomics of childhood obesity. Methods: The PRISMA Platform systematic review rules were followed. The research was carried out from February to April 2024 in the Scopus, PubMed, Science Direct, Scielo and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: 110 articles were recruited for the initial evaluation. A total of 41 articles were evaluated and 19 were included in this systematic review. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 28 studies with a high risk of bias and 28 studies that did not meet GRADE. Most studies showed homogeneity in their results, with X2=58.7%&gt;50%. It was concluded that miRNAs are potential biomarkers for the development of pathologies, such as obesity. A heterogeneous group of these molecules was found to be associated with obesity in children. miR-15b-5p, miR-486-5p and hsa-miR-122-5p were considered good candidates for childhood obesity biomarkers. MiRNA-dependent mechanisms regulate up to 60% of all human genes. MiRNAs influence multiple pathways, including insulin signaling, immune-mediated inflammation, adipokine expression, adipogenesis, lipid metabolism, and regulation of food intake.

Molecular aspects of hereditary complement component C5 deficiency in humans

IntroductionThe complement system plays a key role in the host defense against pathogens. The deficiency of complement components predisposes the system to recurrent infections and autoimmune diseases. In particular, serum C5 deficiency (C5D) may be serious for human health, because this protein plays a key role in controlling infections, mainly with &lt;i&gt;Neisseria&lt;/i&gt; spp.AimThe aim of this article is to present the structure and function of the human C5 gene encoding complement component C5, with particular regard to the molecular characteristics of the mutations causing hereditary complement C5 deficiency.Material and methodsThis article is based on the available literature. A total of 35 articles were included in the study.Results and discussionBased on the literature review, it was shown that C5 mediates inflammatory processes and bacterial cytolysis. The cause of hereditary C5 deficiency in humans is inefficient or reduced serum C5 biosynthesis, due to mutations in the C5 gene. This quantitative and functional C5 deficiency is associated with recurrent &lt;i&gt;Neisseria&lt;/i&gt; spp. infections, the lack of bactericidal activity and an impaired ability of serum to induce chemotaxis. The molecular characterization of previously described C5D-related mutations in the human C5 gene has been performed, and the clinical presentation of some molecularly examined C5D probands has also been discussed.ConclusionsThe deficiency of C5 protein, which bridges innate and adaptive immunity, is related with 18 different mutations in the C5 gene found in over 30 families of various origins. Screening for complement defects seems particularly important, especially in asymptomatic relatives of probands.

Amazon tropical fishes of commercial interest show human-cell contamination but no SARS-CoV-2 in a real-life scenario.

Amazonas was one of the most impacted Brazilian states by the COVID-19 pandemic. Mortality rates were high, and the health systems collapsed. It is important to identify possible intermediate reservoirs to avoid animal-to-human contamination. Several tropical fish are of commercial interest and are sold in large open-air markets in the region, representing a large economic and dietary importance. This study aimed to verify if fish species of commercial importance, aerosols, and fish wastewater in local open-air markets, at a major capital city in the western Brazilian Amazon, are contaminated by SARS-CoV-2. 488 fish, 50 aerosol, and 45 wastewater samples were analyzed for the presence of SARS-CoV-2. The samples were subjected to extraction using the BIOGENE Viral DNA/RNA Extraction kit, and the molecular diagnosis was tested for SARS-CoV-2 using the Bio-Manguinhos SARS-CoV-2 (EDx) Molecular Kit. It was not possible to detect the virus (Ct≤40, for Gene E) in these samples, however, in 181 samples of fish it was possible to detect the human RP gene (Ct≤35, for the RP Gene), indicating human contact. There was a high number of COVID-19 diagnoses in all city districts in which the samples were collected, showing that SARS-CoV-2 was circulating. This study indicates that fish of local commercial importance do not carry SARS-CoV-2 viral particles, despite circulation of SARS-CoV-2, and are not an important source of animal-to-human contamination. Despite these results, the human RP gene was found detectable in fish, air, and fish wastewater, showing that such places may carry human pathogens.

Meta-analysis of six dairy cattle breeds reveals biologically relevant candidate genes for mastitis resistance

BackgroundMastitis is a disease that incurs significant costs in the dairy industry. A promising approach to mitigate its negative effects is to genetically improve the resistance of dairy cattle to mastitis. A meta-analysis of genome-wide association studies (GWAS) across multiple breeds for clinical mastitis (CM) and its indicator trait, somatic cell score (SCS), is a powerful method to identify functional genetic variants that impact mastitis resistance.ResultsWe conducted meta-analyses of eight and fourteen GWAS on CM and SCS, respectively, using 30,689 and 119,438 animals from six dairy cattle breeds. Methods for the meta-analyses were selected to properly account for the multi-breed structure of the GWAS data. Our study revealed 58 lead markers that were associated with mastitis incidence, including 16 loci that did not overlap with previously identified quantitative trait loci (QTL), as curated at the Animal QTLdb. Post-GWAS analysis techniques such as gene-based analysis and genomic feature enrichment analysis enabled prioritization of 31 candidate genes and 14 credible candidate causal variants that affect mastitis.ConclusionsOur list of candidate genes can help to elucidate the genetic architecture underlying mastitis resistance and provide better tools for the prevention or treatment of mastitis, ultimately contributing to more sustainable animal production.