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Hossain, T.

Publications and source records attributed to Hossain, T..

13 recordsLinked to original sources

Integrating bacterial and viral genomic information enhances and extends the machine learning predictions of bacteriophage activity against pathogenic Escherichia coli

The use of bacteriophage (phage) to treat bacterial infections is undergoing a resurgence due to the rise of antibiotic resistance. Pathogenic Escherichia coli, including extraintestinal pathotypes such as uropathogenic E. coli (UPEC), pose a substantial clinical burden with the challenge of multi-drug resistance strains, making it important to progress alternative treatment options such as those based on phage. One major hurdle is selecting effective phage combinations against an infecting strain while accounting for the multiple mechanisms that determine phage susceptibility and bacterial resistance. We previously analysed over 9000 interactions between 31 phage and 314 sequenced E. coli and built machine learning models to predict phage activity against "unseen" E. coli based on these scores and bacterial genome sequence data. However, this approach did not leverage phage gene content, limiting its ability to generalise across phage. Here, we advance this framework by combining bacterial and phage pangenomes into a single predictive model, allowing gene content across related phage as well as bacteria to be incorporated as machine learning features. This unified approach increased predictive accuracy relative to the single-phage models and produced a single model capable of predicting previously unseen phage-E. coli interactions. In leave-phage-out analyses, it also predicted activity for phages whose interaction data were entirely excluded from training. The genomic features most consistently contributing to prediction included bacterial determinants of surface recognition and anti-phage defence, alongside phage-associated features, indicating that this combined model, termed "PanPhage", captures genetic information relevant to multiple stages of the phage-host interaction.

microbiology↗

Hepatitis B virus protein X promotes hepatocyte plasticity and survival in a differentiated human liver organoid system

Background & AimsHepatitis B virus (HBV) drives hepatocellular carcinoma in part through the activity of its X protein (HBx), yet the mechanisms by which HBx alters hepatocyte function remain incompletely understood. Progress has been limited by the lack of relevant human models that support controlled HBx expression in mature hepatocytes. Here, we use an improved hepatocyte-like organoid (HLO) platform that supports enhanced hepatocyte maturation to investigate HBx function in a differentiated hepatocyte context. MethodsAdult stem cell-derived HLOs were differentiated using an optimized protocol to generate hepatocyte-like cells with enhanced maturation and transcriptional similarity to primary liver tissue. HBx function was interrogated using both cognate promoter-driven expression and doxycycline-inducible systems across multiple donor-derived organoid lines. Transcriptomic, pathway, and single-cell imaging analyses were performed to assess the impact of HBx expression on hepatocytes. ResultsHBx expression consistently suppressed apoptosis-associated transcripts and reduced expression of core hepatocyte identity genes, including CYP3A4. Pathway analysis revealed downregulation of liver-specific functions, including metabolism, detoxification, complement, and coagulation. At the single-cell level, higher HBx expression was associated with reduced caspase 3/7 activation following apoptotic challenge and decreased hepatocyte marker expression. Functionally, HBx expression increased resistance to apoptosis and enhanced the ability of differentiated hepatocyte-like cells to revert to a proliferative, less differentiated state. ConclusionsHBx expression in differentiated human liver organoids reduces apoptosis and impairs hepatocyte identity, consistently across donors and expression systems. These findings support a model in which HBx promotes a survival-permissive less differentiated state that may contribute to early HBV-driven tumorigenesis. This HLO platform provides a relevant system to dissect HBV-host interactions and reveals a mechanism by which HBV may prime the liver for malignant transformation. Impact and implicationsUnderstanding how HBV promotes hepatocellular carcinoma remains a critical challenge, partly due to the lack of physiologically relevant human derived model systems to study HBx function. Using a differentiated adult human liver organoid system, we show that HBx simultaneously suppresses apoptosis and disrupts hepatocyte identity, providing a mechanistic framework for how HBV may prime hepatocytes for malignant transformation. These findings are particularly relevant for researchers studying HBV pathogenesis and liver cancer, as well as for clinicians aiming to better understand early disease progression. While further validation in more complex multicellular systems is needed, this platform can support the identification of HBx-targeted therapeutic strategies and guide the development of improved adult human derived models for virus-host interaction studies.

cell biology↗

Quorum sensing and capsule expression enable subpopulation evasion of phage killing in Escherichia coli ST131: Implications for targeted therapy

Escherichia coli ST131 is a globally disseminated multidrug-resistant lineage frequently associated with recalcitrant urinary tract infections (UTIs) and bacteraemia. While bacteriophages offer a promising alternative treatment to antibiotics, their efficacy is often limited in physiologically relevant conditions in comparison to laboratory media. In this study, we have investigated the mechanisms by which the representative ST131 strain, EC958, evades elimination by a model phage, LUC4. We observed that in the urine environment, EC958 can transiently resist phage infection by a density dependent mechanism and by the production of protective polysaccharides. Based on this understanding, we developed a phage treatment strategy that can sterilise an EC958 culture in urine-based medium, even at high bacterial densities. The rational design of the successful phage therapy strategy utilises a tailored phage cocktail containing phage that encode depolymerase enzymes to degrade bacterial surface carbohydrates and the targeting of multiple receptors to prevent the emergence of fixed genetic resistant mutants. We found the addition of specific carbon sources renders the bacteria more susceptible to phage infection. By combining these findings with a simulated bladder wash to model voiding, we successfully achieved elimination of EC958 cultures in a urine environment. This study provides a framework for overcoming both fixed and reversible phage resistance, offering a translatable strategy for effectively treating urinary tract infections with phage. Author SummaryIn this study, we investigated how bacterial populations can overcome a phage infection. Phage are viruses that naturally kill bacteria and provide an alternative treatment to antibiotics. We focussed on a particularly aggressive and antibiotic resistant strain of E. coli, EC958, which belongs to a group of E. coli strains that are a leading cause of urinary tract infections and life-threatening bloodstream infections worldwide. We found that in a simulated bladder environment, these bacteria do not rely on genetic mutations to survive but they employ a range of hide and seek strategies. We showed that bacteria can coat themselves in a protective layer to block the phage and use social signalling to enter a dormant state when cell density is high. When they are in this sleep-like state the phage cannot successfully infect. To overcome these bacterial defences, we developed a treatment strategy combining effective phage with specific naturally occurring additives, that trick the bacteria into waking up and becoming vulnerable again to phage infection. By also simulating a clinical bladder wash to reduce bacterial numbers and therefore reduce social-signalling, we were able to eliminate the bacterial population. Our findings suggest that by understanding bacterial strategies we can design more effective and personalised phage therapies to treat bacterial infections.

microbiology↗

Larger inducible reservoir and higher abundance of exhausted CD8+ T cells in people treated after late versus non-late diagnosis of chronic HIV one year after ART initiation

Background Despite effective antiretroviral therapy, HIV-1 remains a global health challenge. Most people living with HIV (PWH) are diagnosed in the chronic stage and around half are diagnosed late globally. Insight into the effect of time of diagnosis and therapy initiation on reservoir dynamics and immune reconstitution within the group with a chronic diagnosis is limited. Methods In this prospective cohort study, PWH diagnosed during the chronic stage (from Fiebig VI) were stratified into late (<350 CD4+ T cells/mm3 or an AIDS-defining illness) or non- late diagnosis subgroups. We analyzed the viral reservoir by IPDA, SQuHIVLa and FISH-Flow, and the immune compartment with the HIV-specific AIM assay and a 45-color spectral flow cytometry panel in the first year after ART initiation. Findings Although proviral DNA decreased during the first year of ART, the inducible reservoir remained stable. One year after ART initiation, exhausted CD8+ T cell abundance correlated significantly with CD4+ T cell count pre-ART. PWH with a late diagnosis had a significantly higher inducible reservoir and lower CD4+ T-cell counts than the non-late HIV diagnosis subgroup. Moreover, the subgroup with a late diagnosis showed higher abundance of exhausted CD8+ T cells, higher expression of activation/exhaustion markers, and lower naive CD4+ T-cell abundance than the non-late diagnosis subgroup. Interpretation Our results show that late diagnosis is associated with a persistently higher inducible viral reservoir and impaired immune recovery. These findings underline the importance of early diagnosis and treatment, and rationalize the use of late diagnosis as a covariate in future cure and reservoir studies.

immunology↗

omicML: An Integrative Bioinformatics and Machine Learning Framework for Transcriptomic Biomarker Identification

IntroductionTranscriptomic biomarker discovery has been a challenge due to variation in datasets and platforms, complexity in statistical and computational methods, integration of multiple programming languages, and intricacy of ML workflow to evaluate biomarkers. Standard workflows necessitate several stages (quality control, normalization, differential expression), typically executed in R or Python, resulting in bottlenecks for non-experts. Existing platforms have alleviated certain challenges by offering graphical interfaces for data loading, normalization, differential gene expression analysis, and functional analysis; nevertheless, they typically do not incorporate integrated machine learning procedures for biomarker selection. MethodIn this regard, we present omicML, an intuitive graphical user interface (GUI) that combines transcriptomic data analysis with machine learning (ML)-based classification via integrating R and Python packages/libraries. It supports both RNA-Seq and microarray data, automating preprocessing (data import, quality control, and normalization) and differential expression analysis. The tool annotates differentially expressed genes (DEGs) with descriptions, gene ontology, and pathway information and incorporates comparative analysis. Our extensive ML pipeline enables both supervised and unsupervised learning, integrates various datasets based on candidate gene signatures, standardizes and eliminates less significant features, benchmarks multiple ML classifiers with robust performance metrics (e.g., AUROC, AUPRC), assesses feature importance, develops single-gene and multi-gene predictive models, and systematically finalizes the biomarker algorithm. All functionalities are available in omicML, hence reducing the barrier for biologists without computational proficiency. ResultIn a case study, omicML identified a six-gene diagnostic model that distinguishes Mpox (monkeypox virus) infections from those caused by other viruses, including SARS-CoV-2, HIV, Ebola, and varicella-zoster. These results illustrate omicMLs capacity to discern clinically relevant biomarkers from complex transcriptome data. ConclusionThrough the unified system, omicML (https://omicml.org), integrating data preprocessing, differential gene expression analysis, annotation, heatmap analysis, dataset integration, batch effect correction, machine learning approach, and functional analysis can diminish technical barriers and accelerates the conversion of expression data into diagnostic insights for clinicians and bench scientists.

bioinformatics↗

Exploring Effector Protein Dynamics and Natural Fungicidal Potential in Rice Blast Pathogen Magnaporthe oryzae

Rice blast, caused by Magnaporthe oryzae, is a severe agricultural disease leading to significant global economic losses. Genetic and genomic investigations have identified crucial genes and pathways involved in its pathogenesis, particularly highlighting effector proteins like AvrPik variants and MAX proteins. These proteins interact with specific Pik alleles on rice chromosome 11, influencing host immune responses. This study focused on 35 plant-derived metabolites known for their antifungal properties, evaluating their potential as fungicidal agents against M. oryzae. Molecular docking analyses identified Hecogenin and Cucurbitacin E as highly effective binders to MAX40 and APIKL2A proteins, respectively, which are pivotal for fungal virulence and immune evasion. Molecular dynamics simulations further validated strong and stable interactions, affirming the therapeutic potential of these compounds. Additional assessments including Lipinskis rule of five criteria and toxicity predictions indicated their suitability for agricultural use. These findings underscore the promise of Hecogenin and Cucurbitacin E as lead candidates in developing novel fungicidal strategies against rice blast, offering prospects for enhanced crop protection and agricultural sustainability.

bioinformatics↗

An isogenic E. coli population gives rise to multiple persister phenotypes

Bacterial persisters are a subpopulation of multidrug-tolerant cells capable of surviving and resuming activity after exposure to bactericidal antibiotic concentrations, contributing to relapsing infections and the development of antibiotic resistance. We challenge the conventional view that persisters are metabolically dormant by providing compelling evidence that an isogenic population of Escherichia coli remains metabolically active in persistence. Our transcriptomic analysis, conducted at various time points following exposure to bactericidal concentrations of ampicillin (Amp), revealed a number of genes with differential expression over time. Some genes were consistently upregulated in Amp treated persisters compared to the untreated controls, a change that can only occur in metabolically active cells capable of increasing RNA levels. Some of these genes have been previously linked to persister cells, while others have not been associated with them before. If persister cells were metabolically dormant, we would expect minimal changes in the gene network across different time points of Amp treatment. However, network analysis revealed major shifts in gene network activity at various time points of antibiotic exposure. These findings reveal that persisters are metabolically active, non-dividing cells, thereby challenging the notion that they are dormant. Significance statementBacterial persisters are a subpopulation renowned for their multidrug tolerance and remarkable ability to survive bactericidal antibiotic treatments; understanding their formation and long-term survival presents significant challenges. These persisters play a critical role in driving antibiotic resistance, underscoring the urgency of deepening our knowledge about them as the threat of resistance continues to escalate. Our study challenges the long-held assumption that persisters are metabolically inactive and that persisters are not as dormant as previously thought.

microbiology↗

SQuHIVLa: A novel assay for Specific Quantification of inducible HIV-1 reservoir by LAMP

Strategies toward HIV-1 cure aim to clear, inactivate, reduce or immunologically control the virus from a pool of latently infected cells such that combination antiretroviral therapy (cART) can be safely interrupted. In order to assess the impact of any putative curative interventions on the size and inducibility of the latent HIV-1 reservoir, robust and scalable assays are needed to precisely quantify the frequency of infected cells containing inducible replication competent HIV-1. Here, we present Specific Quantification of Inducible HIV-1 by LAMP (SQuHIVLa), a novel assay that leverages the high sensitivity and specificity of RT-LAMP, performed in a single reaction, to detect and quantify cells expressing Tat/Rev msRNA upon activation. Our LAMP primer/probe design exclusively detects subtype-specific HIV-1 Tat/Rev msRNA and exhibits high sensitivity, specificity, and reproducibility. Using SQuHIVLa we quantified the inducible viral reservoir in CD4+ T cells from a diverse group of people living with HIV-1 subtypes B and C on cART. SQuHIVLa presents a high throughput, scalable and specific HIV-1 reservoir quantification tool that is amenable to resource limited settings.

microbiology↗

RAB7 deficiency impairs pulmonary artery endothelial function and promotes pulmonary hypertension

Pulmonary arterial hypertension (PAH) is a devastating and progressive disease with limited treatment options. Endothelial dysfunction plays a central role in development and progression of PAH, yet the underlying mechanisms are incompletely understood. The endosome-lysosome system is important to maintain cellular health and the small GTPase RAB7 regulates many functions of this system. Here, we explored the role of RAB7 in endothelial cell (EC) function and lung vascular homeostasis. We found reduced expression of RAB7 in ECs from PAH patients. Endothelial haploinsufficiency of RAB7 caused spontaneous PH in mice. Silencing of RAB7 in ECs induced broad changes in gene expression revealed via RNA sequencing and RAB7 silenced ECs showed impaired angiogenesis, expansion of a senescent cell fraction, combined with impaired endolysosomal trafficking and degradation, which suggests inhibition of autophagy at the pre-degradation level. Further, mitochondrial membrane potential and oxidative phosphorylation were decreased, and glycolysis was enhanced. Treatment with the RAB7 activator ML-098 reduced established PH in chronic hypoxia/SU5416 rats. In conclusion, we demonstrate here for the first time the fundamental impairment of EC function by loss of RAB7 that leads to PH and show RAB7 activation as a potential therapeutic strategy in a preclinical model of PH.

physiology↗

Escherichia coli cells are primed for survival before lethal antibiotic stress

Non-genetic factors can cause significant fluctuations in gene expression levels. Regardless of growing in a stable environment, this fluctuation leads to cell-to-cell variability in an isogenic population. This phenotypic heterogeneity allows a tiny subset of bacterial cells in a population, referred to as persister cells, to tolerate long-term lethal antibiotic effects by entering into a non-dividing, metabolically altered state. One fundamental question is whether this heterogeneous persister population is due to a pre-existing genetic mutation or a result of a transiently-primed reversible cell state. To explore this, we tested clonal populations starting from a single cell using a modified Luria-Delbruck fluctuation test. Through we kept the conditions the same, the diversity in persistence level among clones was relatively consistent: varying from [~]60-100 and [~]40-70 fold for ampicillin (Amp) and apramycin (Apr), respectively. Then we divided and diluted each clone to observe whether the same clone had comparable persister levels for more than one generation. Replicates had similar persister levels even when clones were divided, diluted by 1:20, and allowed to grow for [~]5 generations. This result explicitly shows a cellular memory passed on for generations and eventually lost when cells are diluted to 1:100 and regrown (>7 generations). Our result demonstrates 1) the existence of a small population prepared for stress ("primed cells") resulting in higher persister numbers, 2) the primed memory state is reproducible and transient, passed down for generations but eventually lost, and 3) a heterogeneous persister population is a result of a transiently-primed reversible cell state and not due to a pre-existing genetic mutation.

synthetic biology↗

SiRNA Molecules as Potential RNAi Therapeutics to Silence RdRP Region and N-Gene of SARS-CoV-2: An In Silico Approach

COVID-19 pandemic keeps pressing onward and effective treatment option against it is still far-off. Since the onslaught in 2020, 13 different variants of SARS-CoV-2 have been surfaced including 05 different variants of concern. Success in faster pandemic handling in the future largely depends on reinforcing therapeutics along with vaccines. As a part of RNAi therapeutics, here we developed a computational approach for predicting siRNAs, which are presumed to be intrinsically active against two crucial mRNAs of SARS-CoV-2, the RNA-dependent RNA polymerase (RdRp), and the nucleocapsid phosphoprotein gene (N gene). Sequence conservancy among the alpha, beta, gamma, and delta variants of SARS-CoV-2 was integrated in the analyses that warrants the potential of these siRNAs against multiple variants. We preliminary found 13 RdRP-targeting and 7 N gene-targeting siRNAs using the siDirect V.2.0. These siRNAs were subsequently filtered through different parameters at optimum condition including macromolecular docking studies. As a result, we selected 4 siRNAs against the RdRP and 3 siRNAs against the N-gene as RNAi candidates. Development of these potential siRNA therapeutics can significantly synergize COVID-19 mitigation by lessening the efforts, furthermore, can lay a rudimentary base for the in silico design of RNAi therapeutics for future emergencies.

bioinformatics↗

Genomic characteristics of recently recognized Vibrio cholerae El Tor lineages associated with cholera in Bangladesh, 1991-2017

Comparative genomic analysis of Vibrio cholerae El Tor associated with endemic cholera in Asia revealed two distinct lineages, one dominant in Bangladesh and the other in India. An in depth whole genome study of V. cholerae El Tor clinical strains isolated during endemic cholera in Bangladesh (1991 - 2017) included reference genome sequence data obtained online. Core genome phylogeny established using single nucleotide polymorphisms (SNPs) showed V. cholerae El Tor strains comprised two lineages, BD-1 and BD-2, which, according to Bayesian phylodynamic analysis, originated from paraphyletic group BD-0 around 1981. BD-1 and BD-2 lineages overlapped temporally but were negatively associated as causative agents of cholera 2004-2017. Genome wide association study (GWAS) revealed 140 SNPs and 31 indels, resulting in gene alleles unique to BD-1 and BD-2. Regression analysis of root to tip distance and year of isolation indicated early BD-0 strains at the base, whereas BD-1 and BD-2 subsequently emerged and progressed by accumulating SNPs. Pangenome analysis provided evidence of gene acquisition by both BD-1 and BD-2, of which six crucial proteins of known function were predominant in BD-2. BD-1 and BD-2 diverged and have distinctively different genomic traits, namely heterogeneity in VSP-2, VPI-1, mobile elements, toxin encoding elements, and total gene abundance. In addition, the observed phage-inducible chromosomal island-like element (PLE1), and SXT ICE elements (ICETET) in BD-2 presumably provided a fitness advantage for the lineage to outcompete BD-1 as the etiological agent of the endemic cholera in Bangladesh, with implications for global cholera epidemiology. ImportanceCholera is a global disease with specific reference to the Bay of Bengal Ganges Delta where Vibrio cholerae O1 El Tor, causative agent of the disease showed two circulating lineages, one dominant in Bangladesh and the other in India. Results of in-depth genomic study of V. cholerae associated with endemic cholera during the past 27 years (1991 - 2017) indicate emergence and succession of the two lineages, BD-1 and BD-2, arising from a common ancestral paraphylatic group, BD-0, comprising the early strains and short-term evolution of the bacterium in Bangladesh. Among the two V. cholerae lineages, BD-2 supersedes BD-1 and is predominant in the most recent endemic cholera in Bangladesh. The BD-2 lineage contained significantly more SNPs and indels, and showed richness in gene abundance, including antimicrobial resistance genes, gene cassettes, and PLE to fight against bacteriophage infection, acquired over time. These findings have important epidemic implications at a global scale.

genomics↗

Antibiotic tolerance, persistence, and resistance of the evolved minimal cell, Mycoplasma mycoides JCVI-Syn3B.

Antibiotic resistance is a growing problem, but bacteria can evade antibiotic treatment via tolerance and persistence. Antibiotic persisters are a small subpopulation of bacteria that tolerate antibiotics due to a physiologically dormant state. Hence, persistence is considered a major contributor to the evolution of antibiotic-resistant and relapsing infections. Here, we used the synthetically developed minimal cell Mycoplasma mycoides JCVI-Syn3B to examine essential mechanisms of antibiotic survival. The minimal cell contains only 473 genes, and most genes are essential. Its reduced complexity helps to reveal hidden phenomenon and fundamental biological principles can be explored because of less redundancy and feedback between systems compared to natural cells. We found that Syn3B evolves antibiotic resistance to different types of antibiotics expeditiously. The minimal cell also tolerates and persists against multiple antibiotics. It contains a few already identified persister-related genes, although lacking many systems previously linked to persistence (e.g. toxin-antitoxin systems, ribosome hibernation genes, etc.).

synthetic biology↗