Biology subjects

Hasan, M. H.

Publications and source records attributed to Hasan, M. H..

4 recordsLinked to original sources

bioRxiv2026

A gavage-fomite based method to generate mouse models with natural microbiota

Laboratory-raised specific pathogen-free (SPF) mice have been indispensable for fundamental immunology research, yet their reliability in predicting human clinical outcomes has been questionable. A major factor contributing to this disconnect is the sanitized housing environment, which deprives laboratory mice of physiological microbial exposure critical for immune maturation. Various approaches have been developed to introduce microbes to SPF mice, aiming to mimic human-like microbial experiences and engender adult human-like immune traits. However, some of these methods, specifically the pet store mice cohousing approach suffer from significant variability in pathogen exposure driven by the uncontrolled nature of microbial exchange and is associated with heightened mortality. Here we present an alternative gavage-fomite (GaF) method that exposes mice to a similarly diverse array of pathogens and commensal as the pet store cohousing method while limiting mortality. GaF-treated mice exhibited consistent gut microbial composition, robust immune maturation characterized by mucosal T-cell distribution, elevated serum inflammatory cytokines, and a splenic immune transcriptional signature closely aligned with that of adult humans. Furthermore, these mice demonstrated enhanced protection against a virulent bacterial challenge. The simplicity, and effectiveness of the GaF method for generating mice with natural microbiota, may support broader use of these models in basic and translational immunological research across institutions.

immunology↗

bioRxiv2025

Gut bacteria gatekeep host-specific colonization of a commensal fungus that boosts type 2 immunity

Naturalized, wilded, wildling, and dirty/pet store mouse models represent a spectrum of approaches designed to make laboratory mice more immunologically and physiologically similar to wild or human contexts by increasing their exposure to naturally occurring microbes and pathogens. In this study, we screened the gut mycobiome of pet store mice, and identified Kazachstania pintolopesii as a dominant fungus in pet store mice across various geographical locations. K. pintolopesii strains isolated from mice in geographically distinct pet stores stably colonize the gastrointestinal tract of laboratory mice, independent of gut bacterial composition, maintaining high fungal burdens for extended periods. K. pintolopesii rapidly became the dominant fungus in the mouse gut in conventional, antibiotic, and germ-free settings, outcompeting other non-murine fungal strains. Pet store-derived K. pintolopesii exhibited unique immunological properties distinct from typical anti-fungal responses. Unlike C. albicans colonization, K. pintolopesii did not induce circulating neutrophil expansion or Th17 cell populations in the gut mucosa. When administered systemically, K. pintolopesii-infected mice showed 100% survival with minimal fungal burden in kidneys, contrasting sharply with lethal C. albicans infections. Adaptive immune deficiency (Rag1 knockout mice) did not affect K. pintolopesii colonization or host response, indicating that B and T cell-mediated immunity does not restrain this fungus. K. pintolopesii colonization provided no cross-protection against systemic candidiasis further establishing lack of immune activation. These findings demonstrate that K. pintolopesii establishes a benign host-fungal relationship through neutrophil-independent mechanisms, avoiding classical anti-fungal immune activation while maintaining stable gut colonization. Instead, it selectively induces strong type 2 mucosal immune responses, increasing tuft and goblet cell counts and stimulating Th2 and group 2 innate lymphoid cell (ILC2) populations. This immune profile confers notable protection against intestinal nematode infection, demonstrated by reduced Heligmosomoides polygyrus egg counts. Altogether, K. pintolopesii serves as an exemplary model for commensal mycobiota, revealing distinct mechanisms for host tolerance and immune modulation.

microbiology↗

bioRxiv2023

Epithelial organoid supports resident memory CD8 T cell differentiation

Resident Memory T cells (TRM) play a vital role in regional immune defense in barrier organs. Although laboratory rodents have been extensively used to study fundamental TRM biology, poor isolation efficiency, sampling bias and low cell survival rates have limited our ability to conduct TRM-focused high-throughput assays. Here, we engineered a murine vaginal epithelial organoid (VEO)-CD8 T cell co-culture system that supports CD8 TRM differentiation in vitro. The three-dimensional VEOs established from murine adult stem cells resembled stratified squamous vaginal epithelium and induced gradual differentiation of activated CD8 T cells into epithelial TRM. These in vitro generated TRM were phenotypically and transcriptionally similar to in vivo TRM, and key tissue residency features were reinforced with a second cognate-antigen exposure during co-culture. TRM differentiation was not affected even when VEOs and CD8 T cells were separated by a semipermeable barrier, indicating soluble factors involvement. Pharmacological and genetic approaches showed that TGF-{beta} signaling played a crucial role in their differentiation. We found that the VEOs in our model remained susceptible to viral infections and the CD8 T cells were amenable to genetic manipulation; both of which will allow detailed interrogation of antiviral CD8 T cell biology in a reductionist setting. In summary, we established a robust model which captures bonafide TRM differentiation that is scalable, open to iterative sampling, and can be subjected to high throughput assays that will rapidly add to our understanding of TRM.

immunology↗

bioRxiv2018

Dynamin is required for efficient cytomegalovirus maturation and envelopment

Cytomegalovirus secondary envelopment occurs in a virus-induced cytoplasmic assembly compartment (vAC) generated via a drastic reorganization of the membranes of the secretory and endocytic systems. Dynamin is a eukaryotic GTPase that is implicated in membrane remodeling and endocytic membrane fission events; however, the role of dynamin in cellular trafficking of viruses beyond virus entry is only partially understood. Mouse embryonic fibroblasts (MEF) engineered to excise all three isoforms of dynamin were infected with mouse cytomegalovirus (MCMV-K181). Immediate early (IE1; m123) viral protein was detected in these triple dynamin knockout (TKO) cells as well as in mock-induced parental MEF at early times post infection although levels were reduced in TKO cells, indicating that virus entry was affected but not eliminated. Levels of IE1 protein and another viral early protein (m04) were normalized by 48 hours post infection; however, late protein (m55; gB) expression was significantly reduced in infected TKO cells compared to parental MEF. Ultrastructural analysis revealed intact stages of nuclear virus maturation in both cases with equivalent numbers of nucleocapsids containing packaged viral DNA (C-capsids) indicating successful viral DNA replication, capsid assembly and genome packaging. Most importantly, severe defects in virus envelopment were visualized in TKO cells but not in parental cells. Dynamin inhibitor (dynasore) treated MEF showed a phenotype similar to TKO cells upon MCMV infection confirming the role of dynamin in late maturation processes. In summary, dynamin-mediated endocytic pathways are critical for the completion of cytoplasmic stages of cytomegalovirus maturation.\n\nImportanceViruses are known to exploit specific cellular functions at different stages of their life cycle in order to replicate, avoid immune recognition by the host and to establish a successful infection. Cytomegalovirus (CMV) infected cells are characterized by a prominent cytoplasmic inclusion (virus assembly compartment; vAC) that is the site of virus maturation and envelopment. While endocytic membranes are known to be the functional components of vAC, knowledge of specific endocytic pathways implicated in CMV maturation and envelopment is lacking. Here we show that dynamin, which is an integral part of host endocytic machinery, is largely dispensable for early stages of CMV infection but is required at a late stage of CMV maturation. Studies on dynamin function in CMV infection will help us understand the host-virus interaction pathways amenable to targeting by conventional small molecules as well as by newer generation nucleotide-based therapeutics (e.g. siRNA, CRISPR/CAS gRNA, etc.).

microbiology↗