Biology subjects

Islam, N.

Publications and source records attributed to Islam, N..

11 recordsLinked to original sources

bioRxiv2026

Neoadjuvant chemotherapy induces transient, regimen-specific immune stromal reprogramming in pancreatic ductal adenocarcinoma

Background: Neoadjuvant chemotherapy (NAC) is increasingly incorporated into the management of pancreatic ductal adenocarcinoma (PDAC), yet how treatment regimen and timing reshape the tumour-immune microenvironment remains poorly defined. Methods: Targeted immune transcriptomic profiling was performed using NanoString on spatially annotated tumour, stromal, and immune-enriched regions from resected PDAC specimens from 23 patients, including NAC-treated and treatment-naive cohorts. Key findings were validated and spatially localised using Xenium in situ transcriptomics. Results: NAC induced extensive transcriptional remodelling of the tumour microenvironment in a regimen- and time-dependent manner. Tumours resected shortly after FOLFIRINOX exhibited coordinated upregulation and strong spatial coupling of the CXCL12-CXCR4 axis. These correlations were attenuated or reversed at longer post-treatment intervals and following gemcitabine-based therapy. Disrupted stromal coordination of the CCL2-CCR2 axis further highlighted context-dependent effects of chemotherapy on chemokine signalling. Across regions, NT5E (CD73) expression inversely correlated with CD8A, consistent with spatially restricted T cell exclusion. Conclusions: NAC dynamically reprograms the immunestromal landscape of PDAC in a regimen- and timing-dependent manner, revealing a transient post-chemotherapy window of immune remodelling. The clinical significance of this phenomenon requires further investigation to determine whether temporally optimised integration of immunomodulatory and stroma-targeted therapies with NAC can improve patient outcomes.

cancer biology↗

bioRxiv2024

Identification of potential inhibitors against Inosine 5'-Monophosphate Dehydrogenase of Cryptosporidium parvum through an integrated in silico approach

The protozoan parasite Cryptosporidium, found in several vertebrates, including humans, is the source of the global infection known as cryptosporidiosis, which manifests as acute gastroenteritis, abdominal pain, and diarrhea. Although infections in certain individuals have been linked to other species, Cryptosporidium parvum is the main cause of illnesses in humans. Lactate Dehydrogenase, Inosine 5'-Monophosphate Dehydrogenase (IMPDH), and several other targets have been identified by the genome sequencing of C. parvum. Bioactive phytochemicals derived from nature have enormous potential as anti-cryptosporidiosis agents. The study aimed to identify new anti-cryptosporidial agents that work against the IMPDH of the parasite by using integrated in silico approaches. In this study, a total of 24 bioactive phytochemicals were screened virtually through molecular docking and ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) analyses. Four lead compounds were identified, including Brevelin A (-8.9 kcal/mol), Vernodalin (-8.7 kcal/mol), Luteolin (-8.6 kcal/mol), and Pectolinarigenin (-8.1 kcal/mol), against the IMPDH protein (PDB ID: 4IXH) from the parasite. All the lead compounds had excellent pharmacokinetic and pharmacodynamic characteristics. The toxicity analysis showed satisfactory results with no major side effects. All of the selected compounds showed no violation of Lipinskis rules of five, indicating the possibility of oral bioavailability as potential drug candidates. In the majority of cases, target class prediction-identified enzymes, as well as investigational and experimental drugs, have been found to have structural similarities to the lead compounds. With significant biochemical interactions, all of the targeted phytochemical compounds have demonstrated excellent pharmacokinetics and better bioavailabilities. The findings strongly recommend in vitro experimental studies to aid in the development of novel therapeutics against Cryptosporidium parvum.

bioinformatics↗

bioRxiv2024

Examining the relationship between psychosocial adversity and inhibitory control: an fMRI study of children growing up in extreme poverty

Exposure to psychosocial adversity (PA) is associated with poor behavioral, physical, and mental health outcomes in adulthood. As these outcomes are related to alterations in developmental processes, growing evidence suggests that deficits in executive functions-inhibitory control in particular-may, in part, explain this relationship. However, literature examining the development of inhibitory control has been based on children in higher resource environments, and little is known how low resource settings might exacerbate the link between inhibitory control and health outcomes. In this context, we collected fMRI data during a Go/No-Go inhibitory control task and PA variables for 68 children 5 to 7 years of age living in Dhaka, Bangladesh, an area with a high prevalence of PA. The childrens mothers completed behavioral questionnaires to assess the childs PA and their own PA. Whole-brain activation underlying inhibitory control was examined using the No-Go versus Go contrast, and associations with PA variables were assessed using whole-brain regressions. Childhood neglect was associated with weaker activation in the right posterior cingulate, whereas greater family conflict, economic stress, and maternal PA factors were associated with greater activation in the left medial frontal gyrus, right superior and middle frontal gyri, and left cingulate gyrus. These data suggest that neural networks supporting inhibitory control processes may vary as a function of exposure to different types of PA, particularly between those related to threat and deprivation. Furthermore, increased activation in children with greater PA may serve as a compensatory mechanism, allowing them to maintain similar behavioral task performance.

neuroscience↗

bioRxiv2023

Phenotypic and genotypic detection of the virulence factors and their association with antibiotic resistance in Enterococcus species

Abstract- Along with the emergence of drug resistant Enterococcal infection, role of various virulence factors in Enterococci is an emerging concept. A number of virulence factors like biofilm formation, hemolysin production, gelatin hydrolysis have important role in the pathogenesis of Enterococci and also associated with antibiotic resistance. The aim of our study was to detect the virulence factors and their encoding genes (asa, gelE, esp, ebpR, hyl gene for biofilm; cylA gene for hemolysis; gelE gene for gelatin hydrolysis) and also observe their association with antimicrobial resistance Enterococci. A total of 87 Enterococci were collected from different clinical samples. Virulence factors were detected phenotypically and antibiotic sensivity were done by Kirby Bauer disc diffusion method. Virulence genes were detected by conventional multiplex PCR and only the ebpR gene was detected by single conventional PCR. Majority of the isolated Enterococci were E. faecalis (75%) followed by E. faecium (23%) and (2%) E. raffinosus were also detected. About 52.3% of E. faecalis and 35% of E. faecium isolates were biofilm producers. Significant association was found between biofilm formation and asa, esp, ebpR genes both in E. faecalis and in E. faecium. Hemolysis was observed phenotypically in 30.8% isolates of E. faecalis and 20% isolates of E. faecium. Significant association was observed between cylA gene and hemolysin production in E. faecalis. Antibiotic resistance were higher in biofilm and hemolysin producing isolates of both species. Resistance to some antibiotics including ampicillin, ciprofloxacin, gentamicin were significantly higher among biofilm and hemolysin producer in E. faecalis.

microbiology↗

bioRxiv2022

EHD2 overexpression promotes tumorigenesis and metastasis in triple-negative breast cancer by regulating store-operated calcium entry

With nearly all cancer deaths a result of metastasis, elucidating novel pro-metastatic cellular adaptations could provide new therapeutic targets. Here, we show that overexpression of the EPS15-Homology Domain-containing 2 (EHD2) protein in a large subset of breast cancers (BCs), especially the triple-negative (TNBC) and HER2+ subtypes, correlates with shorter patient survival. The mRNAs for EHD2 and Caveolin-1/2, structural components of caveolae, show co-overexpression across breast tumors, predicting shorter survival in basal-like BC. EHD2 shRNA knockdown and CRISPR-Cas9 knockout of EHD2, together with mouse EHD2 rescue, in TNBC cell line models demonstrate a major positive role of EHD2 in promoting tumorigenesis and metastasis. Mechanistically, we link these roles of EHD2 to store-operated calcium entry (SOCE), with EHD2-dependent stabilization of plasma membrane caveolae ensuring high cell surface expression of the SOCE-linked calcium channel Orai1. The novel EHD2-SOCE oncogenic axis represents a potential therapeutic target in EHD2 and CAV1/2-overexpressing BC.

cancer biology↗

bioRxiv2022

Short-course but not prolonged treatment with ATR inhibitor AZD6738 integrates with radiotherapy to generate a tumor antigen-specific CD8+ T cell expansion in the periphery

ATR kinase is a central regulator of the DNA damage response. While ATR kinase inhibitors (ATRis) are known to sensitize cancer cells to DNA damage, their effect on immune cells is not known. Here we show in mice that short-course AZD6738 (ATRi) on days 1-3 decreases proliferating T cells in the tumor and periphery and that cessation of ATRi causes a proliferative rebound. Integrating radiation on days 1-2 (RT) with ATRi on days 1-3 increases IFN-{beta} in the tumor and activates tumor antigen-specific CD8+ T cells in the tumor-draining lymph node (DLN). RT with short-course ATRi induces an expansion of tumor antigen-specific CD8+ T cells in the DLN. In contrast, RT with prolonged daily ATRi blocks expansion of antigen-specific CD8+ T cells, despite increased IFN-{beta} and activation of CD8+ T cells. Our data identifies critical schedule considerations for ATRi with RT, immunotherapy and genotoxic therapies.

cancer biology↗

bioRxiv2021

Brain Morphometry and Chronic Inflammation in Bangladeshi Children Growing up in Extreme Poverty

Over three hundred million children live in environments of extreme poverty, and the biological and psychosocial hazards endemic to these environments often expose these children to infection, disease, and inflammatory responses. Chronic inflammation in early childhood has been associated with diminished cognitive outcomes, and despite this established relationship, the mechanisms explaining how inflammation affects brain development are not well known. Importantly, the prevalence of chronic inflammation in areas of extreme poverty raises the possibility that it may serve as a mechanism explaining the known relationship between low socioeconomic status (SES) and altered brain development. To examine these potential pathways, seventy-nine children growing up in an extremely poor, urban area of Bangladesh underwent MRI scanning at six years of age. Structural brain images were submitted to Mindboggle software, a Docker-compliant and high-reproducibility tool for regional estimations of volume, surface area, cortical thickness, sulcal depth, and mean curvature. C-reactive protein was assayed at eight time points between infancy and five years of age and the frequency with which children had elevated concentrations of inflammatory marker represented the measure of chronic inflammation. Childhood SES was measured with maternal education and income-to-needs (i.e., monthly household income divided by the number of household members). Chronic inflammation predicted volume in bilateral basal ganglia structures and mediated the link between maternal education and bilateral putamen volumes. These findings suggest that chronic inflammation is associated with brain morphometry in the basal ganglia, predominantly the putamen, and further offers inflammation as a potential mechanism linking SES to brain development.

neuroscience↗

bioRxiv2021

Peptidoglycan recycling contributes to outer membrane integrity and carbapenem tolerance in Acinetobacter baumannii

The Gram-negative cell envelope is an essential structure that not only protects the cell against lysis from the internal turgor, but also forms a barrier to limit entry of antibiotics. Some of our most potent bactericidal antibiotics, the {beta}-lactams, exploit the essentiality of the cell envelope by inhibiting its biosynthesis, typically inducing lysis and rapid death. However, many Gram-negative bacteria exhibit "antibiotic tolerance", the ability to sustain viability in the presence of {beta}-lactams for extended time periods. Despite several studies showing that antibiotic tolerance contributes directly to treatment failure, and is a steppingstone in acquisition of true resistance, the molecular factors that promote intrinsic tolerance are not well-understood. Acinetobacter baumannii is a critical-threat nosocomial pathogen notorious for its ability to rapidly develop multidrug resistance. While typically reserved to combat multidrug resistant infections, carbapenem {beta}-lactam antibiotics (i.e., meropenem) are first-line prescriptions to treat A. baumannii infections. Meropenem tolerance in Gram-negative pathogens is characterized by morphologically distinct populations of spheroplasts, but the impact of spheroplast formation is not fully understood. Here, we show that susceptible A. baumannii clinical isolates demonstrate high intrinsic tolerance to meropenem, form spheroplasts with the antibiotic and revert to normal growth after antibiotic removal. Using transcriptomics and genetics screens, we characterized novel tolerance factors and found that outer membrane integrity maintenance, drug efflux and peptidoglycan homeostasis collectively contribute to meropenem tolerance in A. baumannii. Furthermore, outer membrane integrity and peptidoglycan recycling are tightly linked in their contribution to meropenem tolerance in A. baumannii. ImportanceCarbapenem treatment failure associated with "superbug" infections has rapidly increased in prevalence, highlighting an urgent need to develop new therapeutic strategies. Antibiotic tolerance can directly lead to treatment failure but has also been shown to promote acquisition of true resistance within a population. While some studies have addressed mechanisms that promote tolerance, factors that underlie Gram-negative bacterial survival during carbapenem treatment are not well-understood. Here, we characterized a role for peptidoglycan recycling in outer membrane integrity maintenance and carbapenem tolerance in A. baumannii. These studies suggest that the pathogen limits antibiotic concentrations in the periplasm and highlights physiological processes that could be targeted to improve antimicrobial treatment.

microbiology↗

bioRxiv2021

Brain Morphometry and Diminished Physical Growth in Bangladeshi Children Growing up in Extreme Poverty: a Longitudinal Study

Diminished physical growth is a common marker of malnutrition and it affects approximately 200 million children worldwide. Despite its importance and prevalence, it is not clear whether diminished growth affects brain development and neurocognitive outcomes. Further, diminished growth is more common in areas of extreme poverty, raising the possibility that it may serve as a mechanism for previously shown links between poverty and brain development. To address these questions, 79 children growing up in an extremely poor, urban area of Bangladesh underwent MRI at 6 years. Structural brain images were submitted to Mindboggle software, a Docker-compliant and highly reproducible tool for tissue segmentation and regional estimations of volume, surface area, cortical thickness, travel depth, and mean curvature. Diminished growth predicted brain morphometry and mediated the link between poverty and brain morphometry most consistently for white matter and subcortical volumes. Meanwhile, brain volume in left pallidum and right ventral diencephalon mediated the relationship between diminished growth and full-scale IQ. These findings offer malnutrition as one possible mechanism by which poverty affects brain development and neurocognitive outcomes in areas of extreme poverty.

neuroscience↗

bioRxiv2020

SARS-CoV-2 genome analysis of strains in Pakistan reveals GH, S and L clade strains at the start of the pandemic

ObjectivesPakistan has a high infectious disease burden with about 265,000 reported cases of COVID-19. We investigated the genomic diversity of SARS-CoV-2 strains and present the first data on viruses circulating in the country. MethodsWe performed whole-genome sequencing and data analysis of SARS-CoV-2 eleven strains isolated in March and May. ResultsStrains from travelers clustered with those from China, Saudi Arabia, India, USA and Australia. Five of eight SARS-CoV-2 strains were GH clade with Spike glycoprotein D614G, Ns3 gene Q57H, and RNA dependent RNA polymerase (RdRp) P4715L mutations. Two were S (ORF8 L84S and N S202N) and three were L clade and one was an I clade strain. One GH and one L strain each displayed Orf1ab L3606F indicating further evolutionary transitions. ConclusionsThis data reveals SARS-CoV-2 strains of L, G, S and I have been circulating in Pakistan from March, at the start of the pandemic. It indicates viral diversity regarding infection in this populous region. Continuing molecular genomic surveillance of SARS-CoV-2 in the context of disease severity will be important to understand virus transmission patterns and host related determinants of COVID-19 in Pakistan.

genomics↗

bioRxiv2019

Relating anthropometric indicators to brain structure in 2-month-old Bangladeshi infants growing up in poverty: a pilot study

Anthropometric indicators, including stunting, underweight, and wasting, have previously been associated with poor neurocognitive outcomes. This link may exist because malnutrition and infection, which are known to affect height and weight, also impact brain structure according to animal models. However, a relationship between anthropometric indicators and brain structural measures has not been tested yet, perhaps because stunting, underweight, and wasting are uncommon in higher-resource settings. Further, with diminished anthropomorphic growth prevalent in low-resource settings, where biological and psychosocial hazards are most severe, one might expect additional links between measures of poverty, anthropometry, and brain structure. To begin to examine these relationships, we conducted an MRI study in 2-3-month-old infants growing up in the extremely impoverished urban setting of Dhaka, Bangladesh. The sample size was relatively small because the challenges of investigating infant brain structure in a low-resource setting needed to be realized and resolved before introducing a larger cohort. Initially, fifty-four infants underwent T1 sequences using 3T MRI, and structural images were segmented into gray and white matter maps, which were carefully evaluated for accurate tissue labeling by a pediatric neuroradiologist. Gray and white matter volumes from 29 infants (79 {+/-} 10 days-of-age; F/M = 12/17), whose segmentations were of relatively high quality, were submitted to semi-partial correlation analyses with stunting, underweight, and wasting, which were measured using height-for-age (HAZ), weight-for-age (WAZ), and weight-for-height (WHZ) scores. Positive semi-partial correlations (after adjusting for chronological age and sex and correcting for multiple comparisons) were observed between white matter volume and HAZ and WAZ; however, WHZ was not correlated with any measure of brain volume. In examining the role of poverty, no associations were observed between income-to-needs or maternal education and brain volumetric measures, suggesting that risk factors previously linked with poverty were not associated with total brain tissue volume pre- or peri-natally in this sample. Overall, these results provide the first link between diminished anthropomorphic growth and white matter volume in infancy. Challenges of conducting a developmental neuroimaging study in a low-resource country are described.

neuroscience↗