Clinical and Molecular Characterization of Hidradenitis Suppurativa: A Practical Framework for Novel Therapeutic Targets.

BACKGROUND: The pathophysiological picture underlying hidradenitis suppurativa (HS) and its syndromic forms is still patchy, thus presenting a great challenge for dermatologists and researchers since just by better understanding the pathogenesis of disease we could identify novel therapeutic targets. METHODS: We propose a practical framework to improve subcategorization of HS patients and support the genotype-phenotype correlation, useful for endotype-directed therapies development. RESULTS: This framework includes (i) clinical work-up that involves the collection of demographic, lifestyle, and clinical data as well as the collection of different biological samples; (ii) genetic-molecular work-up, based on multi-omics analysis in combination with bioinformatics pipelines to unravel the complex etiology of HS and its syndromic forms; (iii) functional studies, - represented by skin fibroblast cell cultures, reconstructed epidermal models (both 2D and 3D) and organoids -, of candidate biomarkers and genetic findings necessary to validate novel potential molecular mechanisms possibly involved and druggable in HS; (iv) genotype-phenotype correlation and clinical translation in tailored targeted therapies. CONCLUSION: Omic findings should be merged and integrated with clinical data; moreover, the skin-omic profiles from each HS patient should be matched and integrated with the ones already reported in public repositories, supporting the efforts of the researchers and clinicians to discover novel biomarkers and molecular pathways with the ultimate goal of providing faster development of novel patient-tailored therapeutic approaches.

Variant Enrichment Analysis to Explore Pathways Disruption in a Necropsy Series of Asbestos-Exposed Shipyard Workers.

The variant enrichment analysis (VEA), a recently developed bioinformatic workflow, has been shown to be a valuable tool for whole-exome sequencing data analysis, allowing finding differences between the number of genetic variants in a given pathway compared to a reference dataset. In a previous study, using VEA, we identified different pathway signatures associated with the development of pulmonary toxicities in mesothelioma patients treated with radical hemithoracic radiation therapy. Here, we used VEA to discover novel pathways altered in individuals exposed to asbestos who developed or not asbestos-related diseases (lung cancer or mesothelioma). A population-based autopsy study was designed in which asbestos exposure was evaluated and quantitated by investigating objective signs of exposure. We selected patients with similar exposure to asbestos. Formalin-fixed paraffin-embedded (FFPE) tissues were used as a source of DNA and whole-exome sequencing analysis was performed, running VEA to identify potentially disrupted pathways in individuals who developed thoracic cancers induced by asbestos exposure. By using VEA analysis, we confirmed the involvement of pathways considered as the main culprits for asbestos-induced carcinogenesis: oxidative stress and chromosome instability. Furthermore, we identified protective genetic assets preserving genome stability and susceptibility assets predisposing to a worst outcome.

Variant Enrichment Analysis to Explore Pathways Functionality in Complex Autoinflammatory Skin Disorders through Whole Exome Sequencing Analysis.

The challenge of unravelling the molecular basis of multifactorial disorders nowadays cannot rely just on association studies searching for potential causative variants shared by groups of patients and not present in healthy individuals; indeed, association studies have as a main limitation the lack of information on the interactions between the disease-causing variants. Thus, new genomic analysis tools focusing on disrupted pathways rather than associated gene variants are required to better understand the complexity of a disease. Therefore, we developed the Variant Enrichment Analysis (VEA) workflow, a tool applicable for whole exome sequencing data, able to find differences between the numbers of genetic variants in a given pathway in comparison with a reference dataset. In this study, we applied VEA to discover novel pathways altered in patients with complex autoinflammatory skin disorders, namely PASH (n = 9), 3 of whom are overlapping with SAPHO) and PAPASH (n = 3). With this approach we have been able to identify pathways related to neutrophil and endothelial cells homeostasis/activations, as disrupted in our patients. We hypothesized that unregulated neutrophil transendothelial migration could elicit increased neutrophil infiltration and tissue damage. Based on our findings, VEA, in our experimental dataset, allowed us to predict novel pathways impaired in subjects with autoinflammatory skin disorders.

Peptides for Coating TiO2 Implants: An In Silico Approach.

Titanium is usually used in the manufacturing of metal implants due to its biocompatibility and high resistance to corrosion. A structural and functional connection between the living bone and the surface of the implant, a process called osseointegration, is mandatory for avoiding prolonged healing, infections, and tissue loss. Therefore, osseointegration is crucial for the success of the implantation procedure. Osseointegration is a process mediated by bone-matrix progenitor cells' proteins, named integrins. In this study, we used an in silico approach to assemble and test peptides that can be strategically used in sensitizing TiO2 implants in order to improve osseointegration. To do so, we downloaded PDB structures of integrins α5ß1, αvß3, and αIIbß3; their biological ligands; and low-cost proteins from the Protein Data Bank, and then we performed a primary (integrin-protein) docking analysis. Furthermore, we modeled complex peptides with the potential to bind to the TiO2 surface on the implant, as well as integrins in the bone-matrix progenitor cells. Then we performed a secondary (integrin-peptide) docking analysis. The ten most promising integrin-peptide docking results were further verified by molecular dynamics (MD) simulations. We recognized 82 peptides with great potential to bind the integrins, and therefore to be used in coating TiO2 implants. Among them, peptides 1 (GHTHYHAVRTQTTGR), 3 (RKLPDATGR), and 8 (GHTHYHAVRTQTLKA) showed the highest binding stability during the MD simulations. This bioinformatics approach saves time and more effectively directs in vitro studies.

CIITA gene polymorphism (rs3087456) in systemic lupus erythematosus and rheumatoid arthritis: A population-based cohort study.

Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are influenced by genetic variants in immune system HLA genes. The Class II Major Histocompatibility Complex Transactivator (CIITA) is an important co-activator of the HLA transcriptional complex; the single nucleotide variant (SNV) rs3087456 localized in the gene promoter region (-168 A/G) has been reported as able to modify its transcription level. In our study, we assessed CIITA rs3087456 SNV in 1,044 Brazilians from two Brazilian regions (Northeast and South) to verify the association with susceptibility and clinical manifestations of (SLE) and (RA) using TaqMan SNP Genotyping Assays System. We observed a protection for a recessive model (GG x AA+AG) for RA susceptibility and increased risk for erosion development in AG genotype patients. No significant association was observed for SLE susceptibility; however, we observed significant increased risk for Class IV and V nephritis development in G allele and GG genotype patients. In conclusion, we showed the contribution of CIITA rs3087456 to SLE or RA clinical features and RA susceptibility in the studied populations.

MMAB, a novel candidate gene to be screened in the molecular diagnosis of Mevalonate Kinase Deficiency.

Mevalonate kinase deficiency (MKD) is an autosomal recessive inflammatory disease. Mutations in MVK gene are associated with MKD with modest genotype-phenotype correlation. In spite of recent guidelines indicating specific MVK mutations for the more severe form or the milder one, little is known about MVK variability within and between populations. The aim of this work is to provide supplementary information about MVK variability useful in the molecular diagnosis of MKD, as well as to unravel the presence of novel genes potentially involved as involved in the clinical heterogeneity of MKD phenotype. We used a population-based approach, coupled with Combined Annotation-Dependent Depletion (CADD) score, to analyze the level of genetic variability for common and putatively deleterious MVK variants. We also performed Exome screening with the Illumina Human Exome Bead Chip on 21 MKD patients to double-check our in silico findings. Haplotype block detection in different populations revealed the existence of two blocks in MVK; interestingly, the first haploblock comprises the promoter region shared with MMAB gene. Analyses of MMAB and MVK genetic variants in 21 MKD patients strengthen our observations showing a novel scenario in which the same mutations commonly associated with MKD are found coupled with different combination of MMAB rs7134594 SNP was already described as associated with HDL cholesterol level and present in the haploblock promoter region. The rs7134594 SNP is reported as an eQTL for MVK and MMAB. Hypothesizing the presence of genetic variants modulating the complex phenotypic spectrum of MKD, we suggest that future directions in screening for MKD pathogenic variants should focus both MMAB and MVK genes.

Iron signature in asbestos-induced malignant pleural mesothelioma: A population-based autopsy study.

Malignant pleural mesothelioma (MPM) is an aggressive cancer with poor prognosis. The development of MPM is frequently linked to inhalation of asbestos fibers. A genetic component of susceptibility to this disease is suggested by the observation that some individuals develop MPM following lower doses of asbestos exposure, whereas others exposed to higher quantities do not seem to be affected. This hypothesis is supported also by frequent reports of MPM familial clustering. Despite the widely recognized role of iron (Fe) in cellular asbestos-induced pulmonary toxicity, the role of the related gene polymorphisms in the etiology of MPM has apparently not been evaluated. Eighty-six single-nucleotide polymorphisms (SNPs) of 10 Fe-metabolism genes were examined by exploiting formalin-fixed paraffin-embedded postmortem samples from 77 patients who died due to MPM (designated AEM) and compared with 48 who were exposed to asbestos but from died in old age of cause other than asbestos (designated AENM). All subjects showed objective signs of asbestos exposure. Three SNPs, localized in the ferritin heavy polypeptide, transferrin, and hephaestin genes, whose frequencies were distributed differently in AEM and AENM populations, were identified. For ferritin and transferrin the C/C and the G/G genotypes, respectively, representing intronic polymorphisms, were significantly associated with protection against MPM and need to be considered as possible genetic markers of protection. Similarly, the C/C hephaestin SNP, a missense variation of this multicopper ferroxidase encoding gene, may be related, also functionally, with protection against MPM. In conclusion, it is proposed that three Fe metabolism-associated genes, significantly associated with protection against development of MPM, may serve as protective markers for this aggressive tumor.

Dendritic Cell-Based Immunotherapies to Fight HIV: How Far from a Success Story? A Systematic Review and Meta-Analysis.

The scientific community still faces the challenge of developing strategies to cure HIV-1. One of these pursued strategies is the development of immunotherapeutic vaccines based on dendritic cells (DCs), pulsed with the virus, that aim to boost HIV-1 specific immune response. We aimed to review DCs-based therapeutic vaccines reports and critically assess evidence to gain insights for the improvement of these strategies. We performed a systematic review, followed by meta-analysis and meta-regression, of clinical trial reports. Twelve studies were selected for meta-analysis. The experimental vaccines had low efficiency, with an overall success rate around 38% (95% confidence interval = 26.7%-51.3%). Protocols differed according to antigen choice, DC culture method, and doses, although multivariate analysis did not show an influence of any of them on overall success rate. The DC-based vaccines elicited at least some immunogenicity, that was sometimes associated with plasmatic viral load transient control. The protocols included both naïve and antiretroviral therapy (ART)-experienced individuals, and used different criteria for assessing vaccine efficacy. Although the vaccines did not work as expected, they are proof of concept that immune responses can be boosted against HIV-1. Protocol standardization and use of auxiliary approaches, such as latent HIV-1 reservoir activation and patient genomics are paramount for fine-tuning future HIV-1 cure strategies.

Meta-analysis of Brazilian genetic admixture and comparison with other Latin America countries.

OBJECTIVES: This study aims at performing a systematic review and meta-analysis with the studies of genetic admixture inference of Brazilian population and to compare these results with the genetic admixture levels in other Latin American countries. METHODS: We searched for articles regarding the estimation of Brazilian genetic admixture published between 1980 and 2014 that used autosomal markers. Then, conducted meta-analyses at the whole-country and regional level. Finally, we compared the results of Brazil with other estimates from other South, Central and North American countries. RESULTS: We analyzed data from 25 studies in 38 different Brazilian populations. European (EUR) ancestry is the major contributor to the genetic background of Brazilians, followed by African (AFR), and Amerindian (AMR) ancestries. The pooled ancestry contributions were 0.62 EUR, 0.21 AFR, and 0.17AMR. The Southern region had a greater EUR contribution (0.77) than other regions. Individuals from the Northeast (NE) region had the highest AFR contribution (0.27) whereas individuals from the North regions had more AMR contribution (0.32). In the Latin America context, Brazil has the 5th high EUR contribution, the 12th for the AFR component and the 10th for the AMR ancestry. CONCLUSIONS: Admixture proportions vary greatly among Brazilian populations and also through Latin America. More studies in the Center-West, North and NE regions are needed to capture a more complete picture of the genomic ancestry of Brazil.

DEFB1 polymorphisms are involved in susceptibility to human papillomavirus infection in Brazilian gynaecological patients.

The human beta defensin 1 (hBD-1) antimicrobial peptide is a member of the innate immune system known to act in the first line of defence against microorganisms, including viruses such as human papillomavirus (HPV). In this study, five functional polymorphisms (namely g-52G>A, g-44C>G and g-20G>A in the 5'UTR and c.*5G>A and c.*87A>G in the 3'UTR) in the DEFB1 gene encoding for hBD-1 were analysed to investigate the possible involvement of these genetic variants in susceptibility to HPV infection and in the development of HPV-associated lesions in a population of Brazilian women. The DEFB1 g-52G>A and c.*5G>A single-nucleotide polymorphisms (SNPs) and the GCAAA haplotype showed associations with HPV-negative status; in particular, the c.*5G>A SNP was significantly associated after multiple test corrections. These findings suggest a possible role for the constitutively expressed beta defensin-1 peptide as a natural defence against HPV in the genital tract mucosa.

Different molecular pathways are disrupted in Pyoderma gangrenosum patients and are associated with the severity of the disease.

Pyoderma gangrenosum (PG) is a rare inflammatory skin disease classified within the spectrum of neutrophilic dermatoses. The pathophysiology of PG is yet incompletely understood but a prominent role of genetics facilitating immune dysregulation has been proposed. This study investigated the potential contribution of disrupted molecular pathways in determining the susceptibility and clinical severity of PG. Variant Enrichment Analysis, a bioinformatic pipeline applicable for Whole Exome Sequencing data was performed in unrelated PG patients. Eleven patients were enrolled, including 5 with unilesional and 6 with multilesional PG. Fourteen pathways were exclusively enriched in the "multilesional" group, mainly related to immune system (i.e., type I interferon signaling pathway), cell metabolism and structural functions. In the "unilesional" group, nine pathways were found to be exclusively enriched, mostly related to cell signaling and cell metabolism. Genetically altered pathways involved in immune system biology and wound repair appear to be nodal pathogenic drivers in PG pathogenesis.

An overview of Zika virus genotypes and their infectivity.

Zika virus (ZIKV) is an enveloped, single-stranded RNA arbovirus belonging to the genus Flavivirus. It was first isolated from a sentinel monkey in Uganda in 1947. More recently, ZIKV has undergone rapid geographic expansion and has been responsible for outbreaks in Southeast Asia, the Pacific Islands, and America. In this review, we have highlighted the influence of viral genetic variants on ZIKV pathogenesis. Two major ZIKV genotypes (African and Asian) have been identified. The Asian genotype is subdivided into Southwest Asia, Pacific Island, and American strains, and is responsible for most outbreaks. Non-synonymous mutations in ZIKV proteins C, prM, E, NS1, NS2A, NS2B, NS3, and NS4B were found to have a higher prevalence and association with virulent strains of the Asian genotype. Consequently, the Asian genotype appears to have acquired higher cellular permissiveness, tissue persistence, and viral tropism in human neural cells. Therefore, mutations in specific coding regions of the Asian genotype may enhance ZIKV infectivity. Considering that mutations in the genomes of emerging viruses may lead to new virulent variants in humans, there is a potential for the re-emergence of new ZIKV cases in the future.

A rare loss-of-function genetic mutation suggest a role of dermcidin deficiency in hidradenitis suppurativa pathogenesis.

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease with a multifactorial aetiology that involves a strict interplay between genetic factors, immune dysregulation and lifestyle. Familial forms represent around 40% of total HS cases and show an autosomal dominant mode of inheritance of the disease. In this study, we conducted a whole-exome sequence analysis on an Italian family of 4 members encompassing a vertical transmission of HS. Focusing on rare damaging variants, we identified a rare insertion of one nucleotide (c.225dupA:p.A76Sfs*21) in the DCD gene encoding for the antimicrobial peptide dermcidin (DCD) that was shared by the proband, his affected father and his 11-years old daughter. Since several transcriptome studies have shown a significantly decreased expression of DCD in HS skin, we hypothesised that the identified frameshift insertion was a loss-of-function mutation that might be associated with HS susceptibility in this family. We thus confirmed by mass spectrometry that DCD levels were diminished in the affected members and showed that the antimicrobial activity of a synthetic DCD peptide resulting from the frameshift mutation was impaired. In order to define the consequences related to a decrease in DCD activity, skin microbiome analyses of different body sites were performed by comparing DCD mutant and wild type samples, and results highlighted significant differences between the groins of mutated and wild type groups. Starting from genetic analysis conducted on an HS family, our findings showed, confirming previous transcriptome results, the potential role of the antimicrobial DCD peptide as an actor playing a crucial part in the etio-pathogenesis of HS and in the maintenance of the skin's physiological microbiome composition; so, we can hypothesise that DCD could be used as a novel target for personalised therapeutic approach.

Biological Pathways Associated With the Development of Pulmonary Toxicities in Mesothelioma Patients Treated With Radical Hemithoracic Radiation Therapy: A Preliminary Study.

Radical hemithoracic radiotherapy (RHR), after lung-sparing surgery, has recently become a concrete therapeutic option for malignant pleural mesothelioma (MPM), an asbestos-related, highly aggressive tumor with increasing incidence and poor prognosis. Although the toxicity associated to this treatment has been reduced, it is still not negligible and must be considered when treating patients. Genetic factors appear to play a role determining radiotherapy toxicity. The aim of this study is the identification of biological pathways, retrieved through whole exome sequencing (WES), possibly associated to the development of lung adverse effects in MPM patients treated with RHR. The study included individuals with MPM, treated with lung-sparing surgery and chemotherapy, followed by RHR with curative intent, and followed up prospectively for development of pulmonary toxicity. Due to the strong impact of grade 3 pulmonary toxicities on the quality of life, compared with less serious adverse events, for genetic analyses, patients were divided into a none or tolerable pulmonary toxicity (NoSTox) group (grade ≤2) and a severe pulmonary toxicity (STox) group (grade = 3). Variant enrichment analysis allowed us to identify different pathway signatures characterizing NoSTox and Stox patients, allowing to formulate hypotheses on the protection from side effects derived from radiotherapy as well as factors predisposing to a worst response to the treatment. Our findings, being aware of the small number of patients analyzed, could be considered a starting point for the definition of a panel of pathways, possibly helpful in the management of MPM patients.

In silico analysis of molecular interactions between HIV-1 glycoprotein gp120 and TNF receptors.

Proinflammatory microenvironmental is crucial for the Human Immunodeficiency Virus Type 1 (HIV-1) pathogenesis. The viral glycoprotein 120 (gp120) must interact with the CD4+ T cell chemokine receptor (CCR5) and a co-receptor C-X-C chemokine receptor type 4 (CXCR4) to let the virus entry into the host cells. However, the interaction of the viral particle with other cell surface receptors is mandatory for its attachment and subsequently entry. Tumor Necrosis Factor receptor type I (TNFR1), type II (TNFR2) and Fas are a superfamily of transmembrane proteins involved in canonical inflammatory pathway and cell death by apoptosis as responses against viral pathogens. In our study, we performed an in silico evaluation of the molecular interactions between viral protein gp120 and TNF receptors (TNFR1, TNFR2 and Fas). Protein structures were retrieved from Protein Databank (PDB), and Molecular Docking and dynamics were performed using ClusPro 2.0 server and GROMACS software, respectively. We observed that gp120 is able to bind TNFR1, TNFR2 and Fas receptors, although only the TNFR2-gp120 complex demonstrated to produce a stable and durable binding. Our findings suggest that gp120 may act as an agonist to TNF-α and also function as an attachment factor in HIV-1 entry process. These molecular interaction by gp120 may be the key to HIV-1 immunopathogenesis. In conclusion, gp120 may stimulate pro-inflammatory and apoptotic signaling transduction pathways mediated by TNFR2 and may act as an attachment factor retaining HIV-1 viral particles on the host cell surface.

Immunoinformatic approach to assess SARS-CoV-2 protein S epitopes recognised by the most frequent MHC-I alleles in the Brazilian population.

AIMS: Brazil is nowadays one of the epicentres of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic and new therapies are needed to face it. In the context of specific immune response against the virus, a correlation between Major Histocompatibility Complex Class I (MHC-I) and the severity of the disease in patients with COVID-19 has been suggested. Aiming at better understanding the biology of the infection and the immune response against the virus in the Brazilian population, we analysed SARS-CoV-2 protein S peptides in order to identify epitopes able to elicit an immune response mediated by the most frequent MHC-I alleles using in silico methods. METHODS: Our analyses consisted in searching for the most frequent Human Leukocyte Antigen (HLA)-A, HLA-B and HLA-C alleles in the Brazilian population, excluding the genetic isolates; then, we performed: molecular modelling for unsolved structures, MHC-I binding affinity and antigenicity prediction, peptide docking and molecular dynamics of the best fitted MHC-I/protein S complexes. RESULTS: We identified 24 immunogenic epitopes in the SARS-CoV-2 protein S that could interact with 17 different MHC-I alleles (namely, HLA-A*01:01; HLA-A*02:01; HLA-A*11:01; HLA-A*24:02; HLA-A*68:01; HLA-A*23:01; HLA-A*26:01; HLA-A*30:02; HLA-A*31:01; HLA-B*07:02; HLA-B*51:01; HLA-B*35:01; HLA-B*44:02; HLA-B*35:03; HLA-C*05:01; HLA-C*07:01 and HLA-C*15:02) in the Brazilian population. CONCLUSIONS: Being aware of the intrinsic limitations of in silico analysis (mainly the differences between the real and the Protein Data Bank (PDB) structure; and accuracy of the methods for simulate proteasome cleavage), we identified 24 epitopes able to interact with 17 MHC-I more frequent alleles in the Brazilian population that could be useful for the development of strategic methods for vaccines against SARS-CoV-2.

Reanalysis of Gene Expression Profiles of CD4+ T Cells Treated with HIV-1 Latency Reversal Agents.

The human immunodeficiency virus (HIV-1) causes a progressive depletion of CD4+ T cells, hampering immune function. Current experimental strategies to fight the virus focus on the reactivation of latent HIV-1 in the viral reservoir to make the virus detectable by the immune system, by searching for latency reversal agents (LRAs). We hypothesize that if common molecular pathways elicited by the presence of LRAs are known, perhaps new, more efficient, "shock-and-kill" strategies can be found. Thus, the objective of the present study is to re-evaluate RNA-Seq assays to find differentially expressed genes (DEGs) during latency reversal via transcriptome analysis. We selected six studies (45 samples altogether: 16 negative controls and 29 LRA-treated CD4+ T cells) and 11 LRA strategies through a systematic search in Gene Expression Omnibus (GEO) and PubMed databases. The raw reads were trimmed, counted, and normalized. Next, we detected consistent DEGs in these independent experiments. AZD5582, romidepsin, and suberanilohydroxamic acid (SAHA) were the LRAs that modulated most genes. We detected 948 DEGs shared by those three LRAs. Gene ontology analysis and cross-referencing with other sources of the literature showed enrichment of cell activation, differentiation and signaling, especially mitogen-activated protein kinase (MAPK) and Rho-GTPases pathways.

Increased risk of dizziness in human immunodeficiency virus-infected patients taking zidovudine and efavirenz combination: a Brazilian cohort study.

OBJECTIVES: Neuropsychiatric adverse effects (NPAE) related to efavirenz, mainly dizziness, is detrimental to human immunodeficiency virus (HIV) treatment. Our study aims at evaluating if zidovudine use potentiates the risk of dizziness related to efavirenz when used together and whether there are significant differences in over time distribution of this NPAE and others relatively frequents regarding efavirenz regimen without zidovudine. METHODS: Human immunodeficiency virus-infected patients under efavirenz-containing different therapy were enrolled. A retrospective analysis of official medical records was accomplished to collect clinical data regarding NPAE occurrence and severity. Univariate statistic and statistical model based on survival analyses were performed. KEY FINDINGS: One hundred sixty-two patients were included, of these seventy-seven (47.5%) had NPAE reported, such as dizziness (more frequent), depression and insomnia. Univariate statistical analysis demonstrated that the combined use of efavirenz with zidovudine increased the NPAE risk (OR: 2.5; P-value: 0.008), mainly dizziness risk (OR: 3.5; P-value: 0.009) and survival analysis showed that such combination is associated with dizziness occurrence faster (HR: 2.9; P-value: 0.02). CONCLUSIONS: The results may contribute to clarify the dizziness occurrence dynamics in therapy with efavirenz and zidovudine by identifying susceptibilities and assisting in the choice of combined antiretroviral therapy.

ZIKA virus entry mechanisms in human cells.

Zika virus (ZIKV) is an enveloped, mosquito-borne Flavivirus, which infects cells through clathrin-mediated endocytosis and fusion employing acidic endosomes. Cell entry is mostly mediated by the viral glycoprotein E, although incomplete particle maturation enables viral protein prM and anionic lipids present in the viral membrane to mediate this process. Incomplete proteolytic maturation results in a set of highly heterogeneous particles. These heterogeneous and dynamic infectious particles offer a variety of possible receptor interaction sites on their surfaces, thus contributing to the wide range of cells susceptible to ZIKV as well as to variation in tissue tropism. This review addresses recent advances in the understanding of ZIKV entry process into cells and put together fundamental questions about viral replication, maturation and host-cell interactions.

Mutational landscape of Zika virus strains worldwide and its structural impact on proteins.

Zika virus (ZIKV) has spread globally and has been linked to the onset of microcephaly and other brain abnormalities. The ZIKV genome consists of an ~10.7 kb positive-stranded RNA molecule that encodes three structural (C, prM and E) and seven nonstructural (5'-NS1-NS2A-NS2B-NS3- NS4A/2K-NS4B-NS5-3') proteins. In this work, we looked for genetic variants in 485 ZIKV complete genomes from GenBank (NCBI) and performed a computational systematic approach using MAESTROweb server to assess the impact of nonsynonymous mutations in ZIKV proteins (C, M, E, NS1, NS2A, NS2B-NS3 protease, NS3 helicase and NS5). Then, we merged the data and correlated it with the phenotypic reports of ZIKV circulating strains. The sensitivity profile of the proteins showed 96 mutational hotspots. We found 22 relevant mutations in proteins C (I80T), NS2A (I34M/T/V, I45V, I80T/V, L113F, A117V, I118V, L128P, V143A, T151A, M199I/V, R207K and L208I) and NS3 helicase (D436G, Y498H, R525K, Q528R and R583K) of the circulating strains. Our analysis exploited the impact of nonsynonymous mutations on ZIKV proteins, their structural and functional insights. The results presented here could advance our current understanding on ZIKV proteins functions and pathogenesis.