Biology subjects

Saha, O.

Publications and source records attributed to Saha, O..

9 recordsLinked to original sources

bioRxiv2022

BIN1 regulates electrical activity and network synchronization in hiPSC-derived neurons

BackgroundBridging Integrator 1 (BIN1) is the second most important Alzheimers disease (AD) risk gene, but its physiological roles in neurons and its contribution to brain pathology remain largely elusive. In this work, we show that BIN1 plays a critical role in the regulation of calcium homeostasis, electrical activity, and gene expression of glutamatergic neurons. MethodsWe generated 3D cerebral organoids and 2D enriched neuronal cell cultures from isogenic BIN1 wild-type (WT), heterozygous (HET) and homozygous knockout (KO) human-induced pluripotent stem cells (hiPSCs). Using single-cell RNA-sequencing, biochemical assays, immunocytochemistry and multi-electrode array(MEA) electrophysiology, we characterized the molecular and functional consequences of reduced BIN1 expression in different neural cell types. ResultsWe show that BIN1 is mainly expressed by oligodendrocytes and glutamatergic neurons of cerebral organoids, like in the human brain. Both BIN1 HET and KO cerebral organoids show specific transcriptional alterations, mainly associated with ion transport and synapses in glutamatergic neurons. We then demonstrate that BIN1 cell-autonomously regulates gene expression in glutamatergic neurons by using a novel protocol to generate pure culture of human-derived induced neurons (hiNs). Using this system, we also show that BIN1 plays a key role in the regulation of neuronal calcium transients and electrical activity via its interaction with the L-type voltage-gated calcium channel Cav1.2. BIN1 KO hiNs show reduced activity-dependent internalization and higher Cav1.2 expression compared to WT hiNs. Pharmacological treatment with clinically relevant doses of nifedipine, a calcium channel blocker, partly rescues neuronal electrical and gene expression alterations in BIN1 KO glutamatergic neurons. Further, we show that transcriptional alterations in BIN1 KO hiNs affecting biological processes related to calcium homeostasis are also present in glutamatergic neurons of the human brain at late stages of AD pathology. ConclusionsTogether, our findings suggest that BIN1-dependent alterations in neuronal properties could contribute to AD pathophysiology and that treatment with low doses of clinically approved calcium blockers should be considered as an option to dampen disease onset and progression.

neuroscience↗

bioRxiv2021

Genome-wide identification and prediction of SARS-CoV-2 mutations show an abundance of variants: Integrated study of bioinformatics and deep neural learning.

Genomic data analysis is a fundamental system for monitoring pathogen evolution and the outbreak of infectious diseases. Based on bioinformatics and deep learning, this study was designed to identify the genomic variability of SARS-CoV-2 worldwide and predict the impending mutation rate. Analysis of 259044 SARS-CoV-2 isolates identify 3334545 mutations (14.01 mutations per isolate), suggesting a high mutation rate. Strains from India showed the highest no. of mutations (48) followed by Scotland, USA, Netherlands, Norway, and France having up to 36 mutations. Besides the most prominently occurring mutations (D416G, F106F, P314L, and UTR:C241T), we identify L93L, A222V, A199A, V30L, and A220V mutations which are in the top 10 most frequent mutations. Multi-nucleotide mutations GGG>AAC, CC>TT, TG>CA, and AT>TA have come up in our analysis which are in the top 20 mutational cohort. Future mutation rate analysis predicts a 17%, 7%, and 3% increment of C>T, A>G, and A>T, respectively in the future. Conversely, 7%, 7%, and 6% decrement is estimated for T>C, G>A, and G>T mutations, respectively. T>G\A, C>G\A, and A>T\C are not anticipated in the future. Since SARS-CoV-2 is evolving continuously, our findings will facilitate the tracking of mutations and help to map the progression of the COVID-19 intensity worldwide.

bioinformatics↗

bioRxiv2021

The Alzheimer's disease genetic risk factor BIN1 induces isoform-dependent neurotoxicity through early endosome defects

The Bridging Integrator 1 (BIN1) gene is a major susceptibility gene for Alzheimers disease (AD). Deciphering its pathophysiological role is challenging due to its numerous isoforms. Here we observed in Drosophila that human BIN1 isoform1 (BIN1iso1) overexpression, contrary to BIN1iso8 and BIN1iso9, induced an accumulation of endosomal vesicles and neurodegeneration. Systematic search for endosome regulators able to prevent BIN1iso1-induced neurodegeneration indicated that a defect at the early endosome level is responsible for the neurodegeneration. In human induced neurons (hiNs) and cerebral organoids, BIN1 knock-out resulted in the narrowing of early endosomes. This phenotype was rescued by BIN1iso1 but not BIN1iso9 expression. Finally, BIN1iso1 overexpression also led to an increase in the size of early endosomes and neurodegeneration in hiNs. Altogether, our data demonstrate that the AD susceptibility gene BIN1, and especially BIN1iso1, contributes to early-endosome size deregulation, which is an early pathophysiological hallmark of AD pathology.

neuroscience↗

bioRxiv2020

Genome-wide diversity and differentiation of two novel multidrug-resistant populations of Pasteurella multocida type B:2 from fowl cholera

Pasteurella multocida is the etiologic agent of fowl cholera (FC), a highly contagious and severe disease in poultry with higher mortality and morbidity. Twenty-two P. multocida strains isolated from the FC outbreaks were subjected to phenotypic and genotypic characterization. The isolates were grouped into two distinct RAPD biotypes harboring a range of pathogenic genes; exbB, ompH, ptfA, nanB, sodC, and hgbA. Among these strains, 90.90% and 36.37% were multidrug-resistant and strong biofilm formers, respectively. Whole genome sequencing of the two representative RAPD isolates confirmed as P. multocida type B:L2:ST122 harboring a number of virulence factors, and antimicrobial resistance genes. Pan-genome analysis revealed 90 unique genes in these genomes associated with versatile metabolic functions, pathogenicity, virulence, and antimicrobial resistance. This study for the first time reports the association of P. multocida genotype B:L2:ST122 in the pathogenesis of FC, and provides a genetic context for future researches on P. multocida strains.

genomics↗

bioRxiv2020

Temporal landscape of mutation accumulation in SARS-CoV-2 genomes from Bangladesh: possible implications from the ongoing outbreak in Bangladesh

Along with intrinsic evolution, adaptation to selective pressure in new environments might have resulted in the circulatory SARS-CoV-2 strains in response to the geoenvironmental conditions of a country and the demographic profile of its population. Thus the analysis of genomic mutations of these circulatory strains may give an insight into the molecular basis of SARS-CoV-2 pathogenesis and evolution favoring the development of effective treatment and containment strategies. With this target, the current study traced the evolutionary route and mutational frequency of 198 Bangladesh originated SARS-CoV-2 genomic sequences available in the GISAID platform over a period of 13 weeks as of 14 July 2020. The analyses were performed using MEGA 7, Swiss Model Repository, Virus Pathogen Resource and Jalview visualization. Our analysis identified that majority of the circulating strains in the country belong to B and/or L type among cluster A to Z and strikingly differ from both the reference genome and the first sequenced genome from Bangladesh. Mutations in Nonspecific protein 2 (NSP2), NSP3, RNA dependent RNA polymerase (RdRp), Helicase, Spike, ORF3a, and Nucleocapsid (N) protein were common in the circulating strains with varying degrees and the most unique mutations(UM) were found in NSP3 (UM-18). But no or limited changes were observed in NSP9, NSP11, E (Envelope), NSP7a, ORF 6, and ORF 7b suggesting the possible conserved functions of those proteins in SARS-CoV-2 propagation. However, along with D614G mutation, more than 20 different mutations in the Spike protein were detected basically in the S2 domain. Besides, mutations in SR-rich region of N protein and P323L in RDRP were also present. However, the mutation accumulation showed an association with sex and age of the COVID-19 positive cases. So, identification of these mutational accumulation patterns may greatly facilitate drug/ vaccine development deciphering the age and the sex dependent differential susceptibility to COVID-19.

bioinformatics↗

bioRxiv2020

Genome-wide Genetic Marker Analysis and Genotyping of Escherichia fergusonii strain OTSVEF-60

Poultry originated Escherichia fergusonii (POEF), an emerging bacterial pathogen, causes a wide range of intestinal and extra-intestinal infections in the poultry industry which incurred significant economic losses worldwide. Chromosomal co-existence of antibiotics and metal resistance genes has recently been the focal point of POEF isolates besides its pathogenic potentials. This study reports the complete genome analysis of POEF strain OTSVEF-60 from the poultry originated samples of Bangladesh. The assembled draft genome of the strain was 4.2 Mbp containing 4,503 coding sequences, 120 RNA (rRNA = 34, tRNA = 79, ncRNA = 7), and three intact phage signature regions. Forty one broad range antibiotic resistance genes (ARGs) including dfrA12, qnrS1, blaTEM-1, aadA2, tet(A) and sul-2 along with multiple efflux pump genes were detected, which translated to phenotypic resistant patterns of the pathogen to trimethoprim, fluoroquinolones, {beta}-lactams, aminoglycoside, tetracycline, and sulfonamides. Moreover, 22 metal resistance genes were found co-existing within the genome of the POEF strain, and numerous virulence genes (VGs) coding for cit (AB), feo (AB), fep (ABCG), csg (ABCDEFG), fliC, ompA gadA, ecpD etc were also identified throughout the genome. In addition, we detected a Class I integron gene cassette harboring dfrA12, ant (3'')-I and qacE{Delta}-sul2) genes, 42 copies of insertion sequence (IS) elements, and two CRISPR arrays. The genomic functional analysis revealed overexpression of several metabolic pathways related to motility, flagellar assembly, epithelial cell invasion, quorum sensing, biofilm formation, and biosynthesis of vitamin, co-factors, and secondary metabolites. We herein for the first time detected multiple ARGs, VGs, mobile genetic elements, and some metabolic functional genes in the complete genome of POEF strain OTSVEF-60, which might be associated with the pathogenesis, spreading of ARGs and VGs, and subsequent treatment failure against this emerging avian pathogen with currently available antimicrobials.

microbiology↗

bioRxiv2020

Multidrug-Resistant Avian Pathogenic Escherichia coli Strains and Association of Their Virulence Genes in Bangladesh

The avian pathogenic Escherichia coli (APEC) strains are the chief etiology of avian colibacillosis worldwide. The present study investigated the circulating phylotypes, existence of virulence genes (VGs) and antimicrobial resistance (AMR) in 392 APEC isolates, obtained from 130 samples belonged to six farms using both phenotypic and PCR-based molecular approaches. Congo red binding (CRB) assay confirmed 174 APEC isolates which were segregated into 10, 9 and 8 distinctive genotypes by RAPD assay (discriminatory index, D=0.8707), BOX-PCR (D=0.8591) and ERIC-PCR (D=0.8371), respectively. The combination of three phylogenetic markers (chuA, yjaA and DNA fragment TspE4.C2) classified APEC isolates into B23 (37.36%), A1 (33.91%), D2 (11.49%), B22 (9.20%) and B1 (8.05%) phylotypes. Majority of the APEC isolates (75-100%) harbored VGs (ial, fimH, crl, papC and cjrC), and of them, VGs (papC and cjrC) and phylotypes (D2 and B2) of APEC had significant (p=0.004) association with colibacillosis. Phylogenetic analysis showed two distinct clades (Clade A and Clade B) of APEC where Clade A had 98-100.0% similarity with E. coli APEC O78 and E. coli EHEC strains, and Clade B had closest relationship with E. coli O169:H41 strain. Interestingly, phylogroups B2 and D2 were found in the APEC strains of both clades while the strains from phylogroups A1 and B1 were found in clade A only. In this study, 81.71% of the isolates were biofilm formers and possessed plasmids of varying ranges (1.0 to 54 kb). In vitro antibiogram profiling revealed that 100.0% isolates were resistant to [≥]3 antibiotics, of which61.96%, 55.24, 53.85, 51.16 and 45.58 % isolates in phylotypes B1, D2, B22, B23 and A1, respectively were these antimicrobials. The resistance patterns varied among different phylotypes, notably in phylotype B22 showing the highest resistance to ampicillin (90.91%), nalidixic acid (90.11%), tetracycline (83.72%) and nitrofurantoin (65.12%). Correspondence analysis also showed significant correlation of phylotypes with CRB (p=0.008), biofilm formation (p=0.02), drug resistance (p=0.03) and VGs (p=0.06). This report demonstrated that B2 and A1 phylotypes are dominantly circulating APEC phylotypes in Bangladesh; however, B2 and D2 are strongly associated with the pathogenicity. A high prevalence of antibiotic resistant APEC strains from different phylotypes suggest to use of organic antimicrobial compounds, and/or metals, and the rotational use of antibiotics in the poultry farms in Bangladesh.

microbiology↗

bioRxiv2020

Epitope-based chimeric peptide vaccine design against S, M and E proteins of SARS-CoV-2 etiologic agent of global pandemic COVID-19: an in silico approach

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the ongoing pandemic of coronavirus disease 2019 (COVID-19), a public health emergency of international concern declared by the World Health Organization (WHO). An immuno-informatics approach along with comparative genomic was applied to design a multi-epitope-based peptide vaccine against SARS-CoV-2 combining the antigenic epitopes of the S, M and E proteins. The tertiary structure was predicted, refined and validated using advanced bioinformatics tools. The candidate vaccine showed an average of [≥] 90.0% world population coverage for different ethnic groups. Molecular docking of the chimeric vaccine peptide with the immune receptors (TLR3 and TLR4) predicted efficient binding. Immune simulation predicted significant primary immune response with increased IgM and secondary immune response with high levels of both IgG1 and IgG2. It also increased the proliferation of T-helper cells and cytotoxic T-cells along with the increased INF-{gamma} and IL-2 cytokines. The codon optimization and mRNA secondary structure prediction revealed the chimera is suitable for high-level expression and cloning. Overall, the constructed recombinant chimeric vaccine candidate demonstrated significant potential and can be considered for clinical validation to fight against this global threat, COVID-19.

microbiology↗

bioRxiv2019

Resistome diversity in bovine clinical mastitis microbiome, a signature concurrence

The bovine clinical mastitis (CM) milk is a large reservoir for diverse groups of resistomes, which play important roles in the pathogenesis of mastitis, but little is known about the concurrence of CM microbiome signature and its associated resistomes. Here we deciphered the total resistance (antibiotics and metals resistance, biofilm formation, quorum sensing) present in CM microbiome using whole metagenome sequencing (WMS) and in vitro cultural approaches. Significant correlation (p=0.001) was found between the resistome diversity and microbiome signature. We identified the strain-level microbiome diversity in four cattle breeds, with microbiome composition represented by the phyla Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria and Fusobacteria (contributing to >95.0% of total strains). However, the resistome diversity did not vary significantly (p=0.692) across the microbiomes of cattle breeds. The in vitro investigation showed that biofilm producing CM pathogens were resistant to most of the conventional antibiotics used for CM treatment, whereas these pathogens remained sensitive to five heavy metals (Cr, Co, Ni, Cu, Zn) at varying concentrations. We also found association of some genomic functional potentials such as bacterial flagellar movement and chemotaxis, regulation and cell signaling, phages-prophages, transposable elements, plasmids and oxidative stress in the pathophysiology of bovine CM. These findings of rapid and reliable identification of CM microbiomes and associated resistomes will help improve the optimization of therapeutic schemes involving antibiotics and metals usage in the prevention and control programs of bovine CM.

microbiology↗