Therapeutic potential of metal ions for COVID-19: insights from the papain-like protease of SARS-CoV-2.

Coronaviruses have been responsible for multiple challenging global pandemics, including coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Papain-like protease (PLpro), one of two cysteine proteases responsible for the maturation and infectivity of SARS-CoV-2, processes and liberates functional proteins from the viral polyproteins and cleaves ubiquitin and ISG15 modifications to inhibit innate immune sensing. Consequently, PLpro is an attractive target for developing COVID-19 therapies. PLpro contains a zinc-finger domain important for substrate binding and structural stability. However, the impact of metal ions on the activity and biophysical properties of SARS-CoV-2 PLpro has not been comprehensively studied. Here, we assessed the impacts of metal ions on the catalytic activity of PLpro. Zinc had the largest inhibitory effect on PLpro, followed by manganese. Calcium, magnesium, and iron had smaller or no effects on PLpro activity. EDTA at a concentration of 0.5 mM was essential for PLpro activity, likely by chelating trace metals that inhibit PLpro. IC50 values for ZnCl2, ZnSO4, and MnCl2 of 0.42 ± 0.02 mM, 0.35 ± 0.01 mM, and 2.6 ± 0.3 mM were obtained in the presence of 0.5 mM EDTA; in the absence of EDTA, the estimated IC50 of ZnCl2 was 14 µM. Tryptophan intrinsic fluorescence analysis confirmed the binding of zinc and manganese to PLpro, and differential scanning calorimetry revealed that zinc but not manganese reduced ΔHcal of PLpro. The results of this study provide a reference for further work targeting PLpro to prevent and treat COVID-19.

PIRD: Pan Immune Repertoire Database.

MOTIVATION: T and B cell receptors (TCRs and BCRs) play a pivotal role in the adaptive immune system by recognizing an enormous variety of external and internal antigens. Understanding these receptors is critical for exploring the process of immunoreaction and exploiting potential applications in immunotherapy and antibody drug design. Although a large number of samples have had their TCR and BCR repertoires sequenced using high-throughput sequencing in recent years, very few databases have been constructed to store these kinds of data. To resolve this issue, we developed a database. RESULTS: We developed a database, the Pan Immune Repertoire Database (PIRD), located in China National GeneBank (CNGBdb), to collect and store annotated TCR and BCR sequencing data, including from Homo sapiens and other species. In addition to data storage, PIRD also provides functions of data visualization and interactive online analysis. Additionally, a manually curated database of TCRs and BCRs targeting known antigens (TBAdb) was also deposited in PIRD. AVAILABILITY AND IMPLEMENTATION: PIRD can be freely accessed at https://db.cngb.org/pird.

Identification of Variable and Joining Germline Genes and Alleles for Rhesus Macaque from B Cell Receptor Repertoires.

The rhesus macaque is a valuable preclinical animal model to estimate vaccine effectiveness and is also important for understanding Ab maturation and B cell repertoire evolution responding to vaccination. However, incomplete mapping of rhesus Ig germline genes hinders the research efforts. To address this deficiency, we sequenced the BCR repertoires of 75 Indian rhesus macaques. Using a bioinformatic method that has been validated with BCR repertoire analysis of three human donors, we were able to infer rhesus variable (V) and joint (J) germline alleles. We identified a total of 122 V and 20 J germline alleles, of which 91 V and 13 J alleles were novel, with 40 V novel genes, of which 8 were located at a novel genomic region not, to our knowledge, previously recorded. The novelty of these newly identified alleles was supported by two observations. First, the 50 V and 5 J novel alleles were observed in the whole genome sequencing data of 10 rhesus macaques. Second, using alignment reference including the novel alleles, the mutation rate of the rearranged repertoires significantly declined in nine other irrelevant samples, and all our identified novel V and J alleles were 100%-identity mapped by rearranged repertoire data. These identified novel alleles, along with the previously reported alleles, provide an important reference for future investigations of rhesus immune repertoire evolution in response to vaccination or infection. In addition, the method outlined in our study offers a powerful foundation for the identification of novel Ig alleles in the future.

Connecting RNA-Modifying Similarities of TDP-43, FUS, and SOD1 with MicroRNA Dysregulation Amidst A Renewed Network Perspective of Amyotrophic Lateral Sclerosis Proteinopathy.

Beyond traditional approaches in understanding amyotrophic lateral sclerosis (ALS), multiple recent studies in RNA-binding proteins (RBPs)-including transactive response DNA-binding protein (TDP-43) and fused in sarcoma (FUS)-have instigated an interest in their function and prion-like properties. Given their prominence as hallmarks of a highly heterogeneous disease, this prompts a re-examination of the specific functional interrelationships between these proteins, especially as pathological SOD1-a non-RBP commonly associated with familial ALS (fALS)-exhibits similar properties to these RBPs including potential RNA-regulatory capabilities. Moreover, the cytoplasmic mislocalization, aggregation, and co-aggregation of TDP-43, FUS, and SOD1 can be identified as proteinopathies akin to other neurodegenerative diseases (NDs), eliciting strong ties to disrupted RNA splicing, transport, and stability. In recent years, microRNAs (miRNAs) have also been increasingly implicated in the disease, and are of greater significance as they are the master regulators of RNA metabolism in disease pathology. However, little is known about the role of these proteins and how they are regulated by miRNA, which would provide mechanistic insights into ALS pathogenesis. This review seeks to discuss current developments across TDP-43, FUS, and SOD1 to build a detailed snapshot of the network pathophysiology underlying ALS while aiming to highlight possible novel therapeutic targets to guide future research.

Characterization of the B Cell Receptor Repertoire in the Intestinal Mucosa and of Tumor-Infiltrating Lymphocytes in Colorectal Adenoma and Carcinoma.

The B cells inhabited in mucosa play a vital role in mediating homeostasis with autoantigens and external Ags. Tumor-infiltrating lymphocytes are potential prognostic markers and therapeutic agents for cancer. However, the spatial heterogeneity of the B cell repertoire in intestinal mucosa and the tumor-infiltrating lymphocytes in colorectal cancer (CRC) remain poorly understood. In this study, we developed an unbiased method to amplify the IgH repertoire, as well as a bioinformatic pipeline to process these high-throughput sequencing data. With biopsies from seven intestinal mucosal segments, we uncovered their strong spatial homogeneity among the large intestine, where the clone overlap rate was up to 62.21%. The heterogeneity between terminal ileum and large intestine was also observed, including discrepant isotype distribution and low clone overlap rate. With tumor and adjacent normal mucosal tissues from CRC and colorectal advanced adenoma (AD) patients, we observed a similar IgH profile between tumor and adjacent normal mucosal tissues in AD, as well as a slight difference in CRC. Interestingly, we found distinct repertoire properties in the CRC tumor from AD and normal mucosa. Finally, we identified 1445 public clones for the normal mucosa, and 22 public clones for the CRC tumor with characteristic features. These data may be of potential use in clinical prognosis, diagnosis, and treatment of CRC.

Differential regulation of cytotoxicity pathway discriminating between HIV, HCV mono- and co-infection identified by transcriptome profiling of PBMCs.

BACKGROUND: Despite the easy accessibility and diagnostic utility of PBMCs and their potential to show distinct expression patterns associated with the accelerated disease progression in HIV/HCV co-infection, there has not been a systematic study focusing on the global dysregulations of the biological pathways in PBMCs from HIV, HCV mono- and co-infected individuals. This study aimed at identifying the transcriptome distinctions of PBMCs between these patient groups. METHODS: Genome-wide transcriptomes of PBMCs from 10 HIV/HCV co-infected patients, 7 HIV+ patients, 5 HCV+ patients, and 5 HIV/HCV sero-negative healthy controls were analyzed using Illumina microarray. Pairwise comparisons were performed to identify differentially expressed genes (DEGs), followed by gene set enrichment analysis (GSEA) to detect the global dysregulations of the biological pathways between HIV, HCV mono- and co-infection. RESULTS: Forty-one, 262, and 44 DEGs with fold change > 1.5 and FDR (false discovery rate) <0.05 for the comparisons of HCV versus co-infection, HIV versus co-infection, and HIV versus HCV were identified, respectively. Significantly altered pathways (FDR < 0.05), featured by those involved in immune system, signaling transduction, and cell cycle, were detected. Notably, the differential regulation of cytotoxicity pathway discriminated between HIV, HCV mono- and co-infection (up-regulated in the former versus the latter group: co-infection versus HIV or HCV, HIV versus HCV; FDR <0.001 ~ 0.019). Conversely, the cytokine-cytokine receptor interaction pathway was down-regulated in co-infection versus either HCV (FDR = 0.003) or HIV (FDR = 0.028). For the comparison of HIV versus HCV, the cell cycle (FDR = 0.016) and WNT signaling (FDR = 0.006) pathways were up- and down-regulated in HIV, respectively. CONCLUSIONS: Our study is the first to identify the differential regulation of cytotoxicity pathway discriminating between HIV, HCV mono- and co-infection, which may reflect the distinct patterns of virus-host cell interactions underlying disease progression. Further inspection of cytotoxicity pathway has pinned down to the expression of the KIR genes to be associated with specific patterns of particular virus-host interactions. Between HIV and HCV, the altered cell cycle and WNT signaling pathways may suggest the different impact of HIV and HCV on cell proliferation and differentiation.

Regulation of gene expression by microRNA in HCV infection and HCV-mediated hepatocellular carcinoma.

MicroRNA (miRNA) exert a profound effect on Hepatitis C virus (HCV) replication and on the manifestation of HCV-associated hepatocellular carcinoma (HCC). miR-122 in particular, is highly enriched in liver and has been shown to interact with HCV, suggesting this virus has evolved to subvert and manipulate the host gene silencing machinery in order to support its life cycle. It is therefore likely that miR-122 and other miRNAs play an important role in the pathophysiology of HCV infection. The changes in post-transcriptional gene regulation by the miRNAs may play a key role in the manifestation of chronic liver disease and hepatocellular carcinoma. Understanding of HCV-host miRNA interactions will ultimately lead to the design of therapeutic modalities against HCV infection and HCV-mediated HCC and may also provide important biomarkers that direct treatment options. Here, we review the current knowledge on the role of miRNA and gene expression on HCV infection and hepatocellular carcinoma, in addition to the possible role of miRNA as future therapeutic targets.

Viruses and neurodegeneration.

Neurodegenerative diseases (NDs) are chronic degenerative diseases of the central nervous system (CNS), which affect 37 million people worldwide. As the lifespan increases, the NDs are the fourth leading cause of death in the developed countries and becoming increasingly prevalent in developing countries. Despite considerable research, the underlying mechanisms remain poorly understood. Although the large majority of studies do not show support for the involvement of pathogenic aetiology in classical NDs, a number of emerging studies show support for possible association of viruses with classical neurodegenerative diseases in humans. Space does not permit for extensive details to be discussed here on non-viral-induced neurodegenerative diseases in humans, as they are well described in literature.Viruses induce alterations and degenerations of neurons both directly and indirectly. Their ability to attack the host immune system, regions of nervous tissue implies that they can interfere with the same pathways involved in classical NDs in humans. Supporting this, many similarities between classical NDs and virus-mediated neurodegeneration (non-classical) have been shown at the anatomic, sub-cellular, genomic and proteomic levels suggesting that viruses can explain neurodegenerative disorders mechanistically. The main objective of this review is to provide readers a detailed snapshot of similarities viral and non-viral neurodegenerative diseases share, so that mechanistic pathways of neurodegeneration in human NDs can be clearly understood. Viruses can guide us to unveil these pathways in human NDs. This will further stimulate the birth of new concepts in the biological research, which is needed for gaining deeper insights into the treatment of human NDs and delineate mechanisms underlying neurodegeneration.

Transcriptome analysis of primary monocytes from HIV-positive patients with differential responses to antiretroviral therapy.

BACKGROUND: Despite the significant contributions of monocytes to HIV persistence, the HIV-monocyte interaction remains elusive. For patients on antiretroviral therapy, previous studies observed a virological suppression rate of >70% and suggested complete viral suppression as the primary goal. Although some studies have reported genetic dysregulations associated with HIV disease progression, research on ex vivo-derived monocytic transcriptomes from HIV+ patients with differential responses to therapy is limited. This study investigated the monocytic transcriptome distinctions between patients with sustained virus suppression and those with virological failure during highly active antiretroviral therapy (HAART). METHODS: Genome-wide transcriptomes of primary monocytes from five HIV+ patients on HAART who sustainably controlled HIV to below detection level (BDL), five HIV+ patients on HAART who consecutively experienced viremia, and four healthy HIV sero-negative controls were analyzed using Illumina microarray. Pairwise comparisons were performed to identify differentially expressed genes followed by quantitative PCR validation. Gene set enrichment analysis was used to check the consistency of our dataset with previous studies, as well as to detect the global dysregulations of the biological pathways in monocytes between viremic patients and BDLs. RESULTS: Pairwise comparisons including viremic patients versus controls, BDL versus controls, and viremic patients versus BDLs identified 473, 76, and 59 differentially expressed genes (fold change > 2 and FDR < 0.05), respectively. The reliability of our dataset was confirmed by gene set enrichment analysis showing that 6 out of 10 published gene lists were significantly enriched (FDR < 0.01) in at least one of the three pairwise comparisons. In the comparison of viremic patients versus BDLs, gene set enrichment analysis revealed that the pathways characterizing the primary functions of monocytes including antigen processing and presentation, FcγR mediated phagocytosis, and chemokine signaling were significantly up-regulated in viremic patients. CONCLUSIONS: This study revealed the first transcriptome distinctions in monocytes between viremic patients and BDLs on HAART. Our results reflected the outcome balanced between the subversion of the monocyte transcriptome by HIV and the compensatory effect adapted by host cells. The up-regulation of antigen presentation pathway in viremic patients particularly highlighted the role of the interface between innate and adaptive immunity in HIV disease progression.

Delayed seroconversion to STLV-1 infection is associated with mutations in the pol and rex genes.

BACKGROUND: Simian T-cell lymphoma/leukemia virus-1 (STLV-1) infection of non-human primates can serve as a model for human T-cell lymphoma/leukemia virus infection. METHODS: Two tantalus and 2 patas monkeys were transfused with intraspecies whole blood infected with STLV-1. Infection was determined by ELISA, western blot and DNA PCR analyses. The entire genome of the STLV-1 Tan 90 strain and some of the STVL-1 Pat74 strain were amplified using over-lapping primer-pairs and subsequently sequenced. RESULTS: Followup studies conducted over 2 years indicated that all 4 monkeys remained healthy despite being infected with STLV-1, as determined by PCR, cloning and sequencing analyses. ELISA and Western blot analyses indicated that both patas monkeys seroconverted within 2 months of transfusion, while one tantalus monkey required one year to seroconvert and the other never fully seroconverted. The tantalus monkey which never fully seroconverted, failed to react to HTLV-1 p24 Gag antigen. Sequence analyses indicated that, while unique, the deduced p24 Gag amino acid sequence of the STLV-1 Tan 90 strain used for infection was still highly homologous to the HTLV-1 p24 Gag amino acids present in the ELISA and WB assays. However, a mutation in the pol sequence of STLV-1 Tan 90 encoded a putative stop codon, while a common deletion in the pol/rex regulatory gene causes significant changes in the Pol, and p27 Rex proteins. These same mutations were also observed in the viral DNA of both recipient infected tantalus monkeys and were not present in the STLV-1 Pat 74 strain. CONCLUSION: Our data suggest that seroconversion to STLV-1 infection may be prolonged due to the above mutations, and that compensatory molecular events must have occurred to allow for virus transmission.

SARS-CoV-2 variants, its recombinants and epigenomic exploitation of host defenses.

Since 2003, we have seen the emergence of novel viruses, such as SARS-CoV-1, MERS, ZIKA, swine flu virus H1N1, Marburg, Monkeypox, Ebola, and SARS-CoV-2, but none of them gained pandemic proportions similar to SARS-CoV-2. This could be attributed to unique viral traits, allowing its rapid global dissemination following its emergence in October 2019 in Wuhan, China, which appears to be primarily driven by the emergence of highly transmissible and virulent variants that also associate, in some cases, with severe disease and considerable mortality caused by fatal pneumonia, acute respiratory distress syndrome (ARDS) in infected individuals. Mechanistically, several factors are involved in viral pathogenesis, and epigenetic alterations take the front seat in host-virus interactions. The molecular basis of all viral infections, including SARS-CoV-2, tightly hinges on the transitory silencing of the host gene machinery via epigenetic modulation. SARS-CoV-2 also hijacks and subdues the host gene machinery, leading to epigenetic modulation of the critical host elements responsible for antiviral immunity. Epigenomics is a powerful, unexplored avenue that can provide a profound understanding of virus-host interactions and lead to the development of epigenome-based therapies and vaccines to counter viruses. This review discusses current developments in SARS-CoV-2 variation and its role in epigenetic modulation in infected hosts. This review provides an overview, especially in the context of emerging viral strains, their recombinants, and their possible roles in the epigenetic exploitation of host defense and viral pathogenesis. It provides insights into host-virus interactions at the molecular, genomic, and immunological levels and sheds light on the future of epigenomics-based therapies for SARS-CoV-2 infection.

A parallel genome-wide mRNA and microRNA profiling of the frontal cortex of HIV patients with and without HIV-associated dementia shows the role of axon guidance and downstream pathways in HIV-mediated neurodegeneration.

BACKGROUND: HIV-associated dementia (HAD) is the most common dementia type in young adults less than 40 years of age. Although the neurotoxins, oxidative/metabolic stress and impaired activity of neurotrophic factors are believed to be underlying reasons for the development of HAD, the genomic basis, which ultimately defines the virus-host interaction and leads to neurologic manifestation of HIV disease is lacking. Therefore, identifying HIV fingerprints on the host gene machinery and its regulation by microRNA holds a great promise and potential for improving our understanding of HAD pathogenesis, its diagnosis and therapy. RESULTS: A parallel profiling of mRNA and miRNA of the frontal cortex autopsies from HIV positive patients with and without dementia was performed using Illumina Human-6 BeadChip and Affymetrix version 1.0 miRNA array, respectively. The gene ontology and pathway analysis of the two data sets showed high concordance between miRNA and mRNAs, revealing significant interference with the host axon guidance and its downstream signalling pathways in HAD brains. Moreover, the differentially expressed (DE) miRNAs identified in this study, in particular miR-137, 153 and 218, based on which most correlations were built cumulatively targeted neurodegeneration related pathways, implying their future potential in diagnosis, prognosis and possible therapies for HIV-mediated and possibly other neurodegenerative diseases. Furthermore, this relationship between DE miRNAs and DE mRNAs was also reflected in correlation analysis using Bayesian networks by splitting-averaging strategy (SA-BNs), which revealed 195 statistically significant correlated miRNA-mRNA pairs according to Pearson's correlation test (P<0.05). CONCLUSIONS: Our study provides the first evidence on unambiguous support for intrinsic functional relationship between mRNA and miRNA in the context of HIV-mediated neurodegeneration, which shows that neurologic manifestation in HIV patients possibly occurs through the interference with the host axon guidance and its downstream signalling pathways. These data provide an excellent avenue for the development of new generation of diagnostic/prognostic biomarkers and therapeutic intervention strategies for HIV-associated neurodegeneration.

Why are the neurodegenerative disease-related pathways overrepresented in primary HIV-infected peripheral blood mononuclear cells: a genome-wide perspective.

We demonstrate for the first time that the genome-wide profiling of HIV-infected peripheral blood mononuclear cells (PBMCs) from HIV-patients free of neurologic disease show overrepresentation of neurodegenerative pathways (Alzheimer's, Parkinson's, ALS, Huntington's and Prion Disease, etc.) in genome-wide microarray analysis, which suggests that this genome-wide representation of neurodegenerative diseases-related pathways in PBMCs could possibly be a subcellular manifestation of neurologic interference by HIV. Further, the cell-tagging analysis attested this belief showing the large majority of genes tagged with cells of monocyte and macrophage lineage, which are implicated in neuronal dysfunction in both viral and non-viral neurodegenerative diseases. Together, these findings suggest that the genomic interference of HIV with neurodegenerative pathways is not by chance, but may be an early sign of HIV-mediated sub-genomic and sub-cellular manifestation of neurologic disease. Moreover, these findings signify the utility of PBMC and genome-wide mapping of the host gene expression as a powerful tool in predicting possible early events in neurologic deterioration in HIV patients.

Genome-wide analysis of primary CD4+ and CD8+ T cell transcriptomes shows evidence for a network of enriched pathways associated with HIV disease.

BACKGROUND: HIV preferentially infects CD4+ T cells, and the functional impairment and numerical decline of CD4+ and CD8+ T cells characterize HIV disease. The numerical decline of CD4+ and CD8+ T cells affects the optimal ratio between the two cell types necessary for immune regulation. Therefore, this work aimed to define the genomic basis of HIV interactions with the cellular transcriptome of both CD4+ and CD8+ T cells. RESULTS: Genome-wide transcriptomes of primary CD4+ and CD8+ T cells from HIV+ patients were analyzed at different stages of HIV disease using Illumina microarray. For each cell subset, pairwise comparisons were performed and differentially expressed (DE) genes were identified (fold change >2 and B-statistic >0) followed by quantitative PCR validation. Gene ontology (GO) analysis of DE genes revealed enriched categories of complement activation, actin filament, proteasome core and proton-transporting ATPase complex. By gene set enrichment analysis (GSEA), a network of enriched pathways functionally connected by mitochondria was identified in both T cell subsets as a transcriptional signature of HIV disease progression. These pathways ranged from metabolism and energy production (TCA cycle and OXPHOS) to mitochondria meditated cell apoptosis and cell cycle dysregulation. The most unique and significant feature of our work was that the non-progressing status in HIV+ long-term non-progressors was associated with MAPK, WNT, and AKT pathways contributing to cell survival and anti-viral responses. CONCLUSIONS: These data offer new comparative insights into HIV disease progression from the aspect of HIV-host interactions at the transcriptomic level, which will facilitate the understanding of the genetic basis of transcriptomic interaction of HIV in vivo and how HIV subverts the human gene machinery at the individual cell type level.

Synthetic long oligonucleotides to generate artificial templates for use as positive controls in molecular assays: drug resistance mutations in influenza virus as an example.

BACKGROUND: Positive controls are an integral component of any sensitive molecular diagnostic tool, but this can be affected, if several mutations are being screened in a scenario of a pandemic or newly emerging disease where it can be difficult to acquire all the necessary positive controls from the host. This work describes the development of a synthetic oligo-cassette for positive controls for accurate and highly sensitive diagnosis of several mutations relevant to influenza virus drug resistance. RESULTS: Using influenza antiviral drug resistance mutations as an example by employing the utility of synthetic paired long oligonucleotides containing complementary sequences at their 3' ends and utilizing the formation of oligonucleotide dimers and DNA polymerization, we generated ~170bp dsDNA containing several known specific neuraminidase inhibitor (NAI) resistance mutations. These templates were further cloned and successfully applied as positive controls in downstream assays. CONCLUSION: This approach significantly improved the development of diagnosis of resistance mutations in terms of time, accuracy, efficiency and sensitivity, which are paramount to monitoring the emergence and spread of antiviral drug resistant influenza strains. Thus, this may have a significantly broader application in molecular diagnostics along with its application in rapid molecular testing of all relevant mutations in an event of pandemic.

Both CD31(+) and CD31⁻ naive CD4(+) T cells are persistent HIV type 1-infected reservoirs in individuals receiving antiretroviral therapy.

BACKGROUND: Naive T cell recovery is critical for successful immune reconstitution after antiretroviral therapy (ART), but the relative contribution of CD31(+) and CD31⁻ naive T cells to immune reconstitution and viral persistence is unknown. METHODS: In a cross-sectional (n = 94) and longitudinal (n = 10) study of human immunodeficiency virus (HIV)-infected patients before and after ART, we examined the ratio of CD31(+) to CD31⁻ naive CD4(+) T cells. In the longitudinal cohort we then quantified the concentration of HIV-1 DNA in each cell subset and performed single-genome amplification of virus from memory and naive T cells. RESULTS: Patients receiving ART had a higher proportion of CD31(+) CD4(+) T cells than HIV-1-infected individuals naive to ART and uninfected control subjects (P < .001 and .007, respectively). After 24 months of ART, the proportion of CD31(+) naive CD4(+) T cells did not change, the concentration of HIV-1 DNA in memory CD4(+) T cells significantly decreased over time (P < .001), and there was no change in the concentration of HIV-1 DNA in CD31(+) or CD31⁻ naive CD4(+) T cells (P = .751 and .251, respectively). Single-genome amplification showed no evidence of virus compartmentalization in memory and naive T cell subsets before or after ART. CONCLUSIONS: After ART, both CD31(+) and CD31⁻ naive CD4(+) T cells expand, and both subsets represent a stable, persistent reservoir of HIV-1.

Epigenetic Lens to Visualize the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) Infection in COVID-19 Pandemic.

In <20 years, we have witnessed three different epidemics with coronaviruses, SARS-CoV, MERS-CoV, and SARS-CoV-2 in human populations, causing widespread mortality. SARS-CoV-2, through its rapid global spread, has led to the pandemic that we call COVID-19. As of February 1, 2021, the global infections linked to SARS-CoV-2 stand at 103,503,340, with 2,236,960 deaths, and 75,108,099 recoveries. This review attempts to highlight host-pathogen interaction with particular emphasis on the role of epigenetic machinery in regulating the disease. Although researchers, since the start of the pandemic, have been intensely engaged in diverse areas to understand the mechanisms involved in SARS-CoV-2 infection to find answers that can bring about innovative ways to swiftly treat and prevent disease progression, this review provides an overview on how the host epigenetics is modulated and subverted by SARS-CoV-2 to enter the host cells and drive immunopathogenesis. Epigenetics is the study that combines genetic and non-genetic factors controlling phenotypic variation, which are primarily a consequence of external and environmental stimuli. These stimuli alter the activity of a gene without impinging on the DNA code. In viral-host interactions, DNA/RNA methylation, non-coding RNAs, chromatin remodeling, and histone modifications are known to regulate and modulate host gene expression patterns. Viruses such as Coronaviruses (an RNA virus) show intrinsic association with these processes. They have evolved the ability to tamper with host epigenetic machinery to interfere with immune sensing pathways to evade host immune response, thereby enhancing its replication and pathogenesis post-entry. These epigenetic alterations allow the virus to weaken the host's immune response to successfully spread infection. How this occurs, and what epigenetic mechanisms are altered is poorly understood both for coronaviruses and other respiratory RNA viruses. The review highlights several cutting-edge aspects of epigenetic work primarily pertinent to SARS-CoV-2, which has been published between 2019 and 2020 to showcase the current knowledge both in terms of success and failures and take lessons that will assist us in understanding the disease to develop better treatments suited to kill SARS-CoV-2.

Destination Amyotrophic Lateral Sclerosis.

Amyotrophic Lateral Sclerosis (ALS) is a prototypical neurodegenerative disease characterized by progressive degeneration of motor neurons both in the brain and spinal cord. The constantly evolving nature of ALS represents a fundamental dimension of individual differences that underlie this disorder, yet it involves multiple levels of functional entities that alternate in different directions and finally converge functionally to define ALS disease progression. ALS may start from a single entity and gradually becomes multifactorial. However, the functional convergence of these diverse entities in eventually defining ALS progression is poorly understood. Various hypotheses have been proposed without any consensus between the for-and-against schools of thought. The present review aims to capture explanatory hierarchy both in terms of hypotheses and mechanisms to provide better insights on how they functionally connect. We can then integrate them within a common functional frame of reference for a better understanding of ALS and defining future treatments and possible therapeutic strategies. Here, we provide a philosophical understanding of how early leads are crucial to understanding the endpoints in ALS, because invariably, all early symptomatic leads are underpinned by neurodegeneration at the cellular, molecular and genomic levels. Consolidation of these ideas could be applied to other neurodegenerative diseases (NDs) and guide further critical thinking to unveil their roadmap of destination ALS.

Hierarchical kernel mixture models for the prediction of AIDS disease progression using HIV structural gp120 profiles.

Changes to the glycosylation profile on HIV gp120 can influence viral pathogenesis and alter AIDS disease progression. The characterization of glycosylation differences at the sequence level is inadequate as the placement of carbohydrates is structurally complex. However, no structural framework is available to date for the study of HIV disease progression. In this study, we propose a novel machine-learning based framework for the prediction of AIDS disease progression in three stages (RP, SP, and LTNP) using the HIV structural gp120 profile. This new intelligent framework proves to be accurate and provides an important benchmark for predicting AIDS disease progression computationally. The model is trained using a novel HIV gp120 glycosylation structural profile to detect possible stages of AIDS disease progression for the target sequences of HIV+ individuals. The performance of the proposed model was compared to seven existing different machine-learning models on newly proposed gp120-Benchmark_1 dataset in terms of error-rate (MSE), accuracy (CCI), stability (STD), and complexity (TBM). The novel framework showed better predictive performance with 67.82% CCI, 30.21 MSE, 0.8 STD, and 2.62 TBM on the three stages of AIDS disease progression of 50 HIV+ individuals. This framework is an invaluable bioinformatics tool that will be useful to the clinical assessment of viral pathogenesis.

Tissue-specific sequence alterations in the human immunodeficiency virus type 1 envelope favoring CCR5 usage contribute to persistence of dual-tropic virus in the brain.

Most human immunodeficiency virus type 1 (HIV-1) strains isolated from the brain use CCR5 for entry into macrophages and microglia. Strains that use both CCR5 and CXCR4 for entry (R5X4 strains) have been identified in the brains of some individuals, but mechanisms underlying the persistence of R5X4 viruses compartmentalized between the brain and other tissue reservoirs are unknown. Here, we characterized changes in the HIV-1 envelope (Env) that enhance the tropism of R5X4 variants for brain or lymphoid tissue. R5X4 Envs derived from the brains of two individuals had enhanced CCR5 usage in fusion assays compared to R5X4 Envs derived from matched spleen or blood, which was associated with reduced dependence on specific residues in the CCR5 N terminus and extracellular loop 1 (ECL1) and ECL3 regions. In contrast, spleen/blood-derived Envs had enhanced CXCR4 usage compared to brain-derived Envs, which was associated with reduced dependence on residues in the CXCR4 N terminus and ECL2 region. Consequently, brain-derived Envs had preferential CCR5 usage for HIV-1 entry into the JC53 cell line, could use either CCR5 or CXCR4 for entry into monocyte-derived macrophages (MDM), and could use CCR5 (albeit inefficiently) for entry into peripheral blood mononuclear cells (PBMC), whereas the entry of spleen-derived Envs was CXCR4 dependent in all three cell types. Mutagenesis studies of Env amino acid variants influencing coreceptor usage showed that S306 in the gp120 V3 region of brain-derived Envs reduces dependence on the CCR5 N terminus and enhances CCR5 usage for HIV-1 entry into PBMC and MDM, whereas R306 in spleen-derived Envs reduces dependence on the CXCR4 N terminus and confers the CXCR4 restricted phenotype. These results identify mechanisms underlying R5X4 HIV-1 persistence in different tissue reservoirs. Tissue-specific changes in the gp120 V3 region that increase the efficiency of CCR5 or CXCR4 usage, and thereby influence coreceptor preference, may enhance the tropism of R5X4 strains for CCR5-expressing macrophage lineage cells in the brain and CXCR4-expressing T cells in lymphoid tissues, respectively.