Biology subjects

Ayasoufi, K.

Publications and source records attributed to Ayasoufi, K..

14 recordsLinked to original sources

bioRxiv2025

Antigen-specific CD8 T cells are generated and reactivated in the bone marrow following viral brain infections and impact the bone marrow niche

Bone marrow is the primary immune organ responsible for stem cell maintenance and hematopoiesis. However, the contribution of the bone marrow niche for the generation of adaptive immune responses is less well-understood. We therefore assessed the capacity of virus antigen-specific CD8 T cells to be generated and expanded in bone marrow following acute neurotropic virus infection. Intracranial infection with the neurotropic Theilers Murine Encephalomyelitis Virus (TMEV) results in an acute infection in the C57BL/6 mouse which is cleared within 4 weeks post infection due to the generation of an antigen-specific CD8 T cell response against the immunodominant epitope VP2121-130. We determined that 1-10% of CD8 T cells present in the femoral, and sternal bone marrow were virus antigen-specific 5-7 days after intracranial TMEV infection. We determined that antigen-specific CD8 T cells were generated in the bone marrow with similar kinetics to that of conventional responses in the secondary lymphoid organs. Importantly, continuous treatment with FTY720, which sequesters T cells outside of the blood, did not eliminate antigen-specific CD8 T cells in the bone marrow compartment indicating generation within the bone marrow niche. Similarly, injection of Poly I:C admixed with fluorescently labeled ovalbumin into the brain generated a similar antigen-specific CD8 T cell response in the bone marrow indicating these responses occur following various brain insults. This model also identified the likely antigen presenting cell (APC) responsible for scavenging antigens from the brain and trafficking into the bone marrow as a migratory myeloid-derived APC. Moreover, following clearance of TMEV infection, CD8 T cells in the bone marrow established durable memory. Antigen-specific memory CD8 T cells in the bone marrow reactivated and expanded upon cognate antigen reencounter. Antigen-specific reactivation of memory CD8 T cells within the bone marrow caused a concurrent increase in Lineage-, Sca-1+, c-Kit+ (LSK) and CD11b+ MHCII+ myeloid cells. This increase in the LSKs and myeloid cells in the bone marrow niche was abrogated with CD8 T cell depletion. We conclude that brain viral infections induce in situ effector and memory T cell responses within the bone marrow compartment. Memory recall CD8 T cell responses induce niche dysregulation by expanding LSK cells and lead to an influx of MHCII+ myeloid cells. Our data pave the way for crucial studies of bone marrow resident antigen-specific CD8 T cells in health and diseases.

immunology↗

bioRxiv2025

Temporal single-cell profiling uncovers age-associated delays in immune resolution to respiratory viral infection

Aging is a major risk factor for increased morbidity and mortality following acute respiratory virus infections. To elucidate the immune determinants underlying viral pathogenesis and delayed lung repair in the aged lung, a comprehensive time-course study was conducted. Single-cell RNA sequencing (scRNAseq) and high-dimensional flow cytometry were utilized to compare lungs from young and aged mice infected with influenza A virus (IAV). Aged hosts displayed diminished alveolar macrophage (AM) and dendritic cell (DC) but elevated monocyte-derived macrophage (MoM) and interstitial macrophage (IM) presence following infection. Additionally, enhanced accumulation of adaptive immune cells, including CD4+ tissue-resident helper (TRH) cells, CD8+ tissue-resident memory (TRM) cells, and a B cell subset resembling age-associated B cells, was observed in the memory phase. Pathway analysis revealed that elevated type I and II interferon (IFN/{gamma}) signaling, especially in MoM/IM subsets, distinguished the aged hosts from the young. Inhibition of IFN/{gamma} signaling after viral clearance improved long-term respiratory outcomes and reduced both IM and TRH populations in aged mice. These findings highlight the pivotal role of IFN/{gamma} signaling, likely within MoM/IM subsets, in driving the exuberant persistence of adaptive immune cells and chronic immunopathology in the aged lung following acute viral infection.

immunology↗

bioRxiv2025

Measles vaccine attenuation comprises innate immune cell infection and interferon responses

Measles virus (MeV) is a highly contagious pathogen capable of infecting immune cells and thereby causing immunosuppression and immune amnesia. A live-attenuated MeV vaccine is highly efficacious and has been safely administered for over 60 years. However, a detailed mechanistic understanding of the mode of its attenuation remains elusive. Here, we determined the molecular mechanisms underlying MeV vaccine attenuation in primary human immune cells. Enhanced infection of innate immune cells resulting in uncontrolled viral RNA synthesis and reduced ability to evade host antiviral responses induced a strong type-I interferon signature that arrested replication of the vaccine strain. In contrast, the wild type virus replicated slowly but steadily, avoiding detection by innate immunity.

immunology↗

bioRxiv2025

Induced Proteinuria Enhances Adeno-Associated Virus Transduction of Renal Tubule Epithelial Cells After Intravenous Administration

A variety of genetic diseases of the kidney tubule are amenable to correction via gene therapy. However, gene delivery to renal tubule epithelial cells mediated by viral vectors via the blood is inefficient due to the permselectivity of the glomerular barrier. We hypothesized that effacement of podocyte foot processes would disrupt typical glomerular limitations on filtration and make renal tubule epithelial cells susceptible to transduction from viral vectors delivered intravenously. We determined that adeno-associated virus serotype 8 (AAV8) transduced significantly more epithelial cells in the kidney under the conditions of LPS-induced proteinuria. Use of AAV1 in tandem with LPS-induced proteinuria yielded an ideal two-pronged effect of both partially detargeting the liver and transducing the kidney with a higher bioluminescent signal than AAV8 did, and at half of the dose. Using adenovirus serotype 5 (Ad5) in conjunction with LPS-induced proteinuria showed that kidney transduction was enhanced, but only in glomerular cells. These studies mechanistically test the efficacy of different viral vectors and demonstrate their capacity to transduce kidney epithelial cells. This is a fundamental step in designing future treatments for kidney gene therapy. Significance StatementThe slit diaphragms in the glomerulus of the kidney are too narrow to allow most solute from the blood to enter the nephron. As a result, large particles such as viral vectors generally cannot access tubule epithelial cells necessary to correct genetic disorders. In this study, mice are induced into a state of proteinuria and subsequently administered viral vectors intravenously. This group of mice had higher levels of transduced kidney epithelial cells than the control (non-proteinuria) group. The induction of transient proteinuria before intravenous viral vector administration is a novel approach that could make tubulopathies treatable via gene therapy in both animal models and humans.

genetics↗

bioRxiv2025

A Spatial Multi-Omic Framework Identifies Gliomas Permissive to TIL Expansion

Tumor-infiltrating lymphocyte (TIL) therapy is effective in several tumor types; however, its feasibility in immune subversive tumors like glioblastoma is unclear. We expanded TILs from glioblastoma specimens and observed marked variability in yield, composition, function, and TCR clonality. By interrogating TILs expanded ex vivo alongside their sourced glioma tissue, we sought to identify determinants of successful (TIL+) vs unsuccessful TIL expansion (TIL-). Expanded TILs were predominantly effector memory CD4 cells and exhibited oligoclonal TCR enrichment. Despite similar T cell abundance in TIL vs TIL- tumors, TIL tumors exhibited distinct spatial organization and cellular interactions, including increased endothelial-immune interactions/ proximity and enrichment of vascular-associated niches. CD4 T cells localized near CD68 macrophages in TIL tumors, while they were positioned near CD163 CD206 macrophages in TIL- tumors. Thus, TIL expansion and functionality are linked to spatial organization and myeloid context; these features may enable biomarker-driven stratification for future TIL therapy in gliomas.

cancer biology↗

bioRxiv2024

Deficiency of Hv1 Proton Channel Enhances Macrophage Antigen Presentation and Anti-Tumor Responses in Glioma

In the tumor microenvironment of glioblastoma, myeloid cells act as a double-edged sword--they are a major cellular component modulating the immune response while presenting a potential therapeutic target. Our study highlights the voltage-gated proton channel Hv1, predominantly expressed in myeloid cells, as a crucial regulator of their physiological functions. We discovered a strong correlation between increased Hv1 expression and poor prognosis in glioblastoma patients. Depleting Hv1 significantly extended survival in a mouse model of glioma. Employing multiple novel transgenic mouse lines, we demonstrated that Hv1 is upregulated in response to tumor presence, with glioma-associated macrophages as the principal contributors. Specifically, we identified that Hv1 in infiltrating macrophages as the major driver of survival phenotype differences. Through a combination of in vivo two-photon imaging, spectral flow cytometry, and spatial transcriptomic sequencing, we found that Hv1 depletion leads to reduced macrophage infiltration and enhanced antigen presentation, ultimately fostering a stronger adaptive immune response. These findings establish the Hv1 channel as a crucial new immune regulator within the brain tumor milieu, offering a promising target for reprogramming macrophage function to combat glioblastoma.

neuroscience↗

bioRxiv2024

TNFR2 loss leads to decreased TOX expression in T cells without affecting TIM3 and improves responses to tumor and chronic LCMV

Exhaustion represents a collection of programmed T cell differentiation states and an important mode of T cell dysfunction. T cell progression from progenitor to terminal exhaustion is associated with upregulation of the transcription factor TOX and expression of TIM3. Our understanding of factors regulating TOX expression and the transition from progenitor to terminal exhaustion, however, remains incomplete. We reveal here that T cell upregulation of tumor necrosis factor receptor type II (TNFR2) coincides with the gain of phenotypic markers and functions reflective of terminal exhaustion. Meanwhile, knocking out TNFR2 affords a novel population of T cells that express TIM3 but possess diminished TOX levels and functional characteristics of both progenitor and terminally exhausted cells. TIM3+ TNFR2 KO T cells exhibit reduced exhaustion transcriptional programs and enhanced AP1 pathway signatures. Finally, TNFR2 KO mice demonstrate improved T cell-dependent control of tumor and chronic lymphocytic choriomeningitis (cLCMV) infection, while pharmacologic antagonism of TNFR2 licenses responses to checkpoint blockade in multiple subcutaneous and intracranial tumor models.

immunology↗

bioRxiv2023

Microglial P2Y6 calcium signaling promotes phagocytosis and shapes neuroimmune responses in epileptogenesis

Microglial calcium signaling is rare in a baseline state but shows strong engagement during early epilepsy development. The mechanism and purpose behind microglial calcium signaling is not known. By developing an in vivo UDP fluorescent sensor, GRABUDP1.0, we discovered that UDP release is a conserved response to seizures and excitotoxicity across brain regions. UDP signals to the microglial P2Y6 receptor for broad increases in calcium signaling during epileptogenesis. UDP-P2Y6 signaling is necessary for lysosome upregulation across limbic brain regions and enhances production of pro-inflammatory cytokines--TNF and IL-1{beta}. Failures in lysosome upregulation, observed in P2Y6 KO mice, can also be phenocopied by attenuating microglial calcium signaling in Calcium Extruder ("CalEx") mice. In the hippocampus, only microglia with P2Y6 expression can perform full neuronal engulfment, which substantially reduces CA3 neuron survival and impairs cognition. Our results demonstrate that calcium activity, driven by UDP-P2Y6 signaling, is a signature of phagocytic and pro-inflammatory function in microglia during epileptogenesis.

neuroscience↗

bioRxiv2023

TREM2 mediates MHCII-associated CD4+ T cell response against gliomas

Triggering receptor expressed on myeloid cells 2 (TREM2) was recently highlighted as a novel immune suppressive marker in peripheral tumors. The aim of this study was to characterize TREM2 expression in gliomas and investigate its contribution in glioma progression by using Trem2-/-mouse line. Our results showed that higher TREM2 expression was correlated with poor prognosis in glioma patients. Unexpectedly, TREM2 deficiency did not have a beneficial effect in a pre-clinical model of glioma. The increased TREM2 expression in glioma was likely due to increased myeloid cell infiltration, as evidenced by our single-cell analysis showing that almost all microglia and macrophages in gliomas were TREM2+. Furthermore, we found that deficiency of TREM2 impaired tumor-myeloid phagocytosis and MHCII presentation, and significantly reduced CD4+ T cells in tumor hemispheres. Our results revealed a previously unrecognized protective role of tumor-myeloid TREM2 in promoting MHCII-associated CD4+ T cell response against gliomas. SUMMARYAuthors found that although higher TREM2 expression is correlated with poor prognosis in glioma patients, its absence has no beneficial effect in a pre-clinical model of glioma. Deficiency of TREM2 impairs myeloid cell phagocytosis of tumor debris, leading to a reduction in MHCII-dependent CD4+ anti-glioma immunity.

neuroscience↗

bioRxiv2022

Antigen presentation by discrete class I molecules on brain endothelium dynamically regulates T-cell mediated neuropathology in experimental cerebral malaria

CD8 T cell engagement of brain vasculature is a putative mechanism of neuropathology in human cerebral malaria. To define contributions of brain endothelial cell MHC class I antigen-presentation to CD8 T cells in establishing this pathology, we developed novel H-2Kb LoxP and H-2Db LoxP mice crossed with Cdh5-Cre mice to achieve targeted deletion of discrete class I molecules on brain endothelium. Using the Plasmodium berghei ANKA model of experimental cerebral malaria (ECM), we observe that H-2Kb and H-2Db regulate distinct patterns of disease onset, CD8 T cell infiltration, targeted cell death, and regional blood-brain barrier (BBB) disruption. Strikingly, ablation of H-2Kb or H-2Db from brain endothelial cells resulted in reduced CD8 T cell activation, attenuated T cell interaction with brain vasculature, lessened targeted cell death, preserved BBB integrity, and prevented ECM and the death of the animal. These data demonstrate that interactions of CD8 T cells with discrete MHC class I molecules on brain endothelium regulate development of ECM neuropathology. Therefore, targeting MHC class I interactions therapeutically may hold potential for treatment of cases of severe malaria.

neuroscience↗

bioRxiv2022

Brain resident memory T cells rapidly expand and initiate neuroinflammatory responses following CNS injury and viral infection

The contribution of circulating verses tissue resident memory T cells (TRM) to clinical neuropathology is an enduring question due to a lack of mechanistic insights. The prevailing view is TRM cells are protective against pathogens in the brain. However, the extent antigen-specific TRM cells can induce neuropathology upon reactivation has not been determined. Using the described phenotype of TRMs, we found that brains of naive mice harbor populations of CD69+ CD103- T cells. Notably, numbers of CD69+ CD103- TRM cells rapidly increase following neurological insults of physical, cancerous, or viral origins. This TRM expansion precedes infiltration of virus specific CD8 T cells and is due to proliferation of T cells within the brain. In contrast, the CD69+ CD103+ TRMs in the brain are generated after the initial expansion of CD69+ CD103- cells following injury and are antigen-specific. We next evaluated the capacity of antigen-specific TRMs in the brain to induce significant neuroinflammation post virus clearance, including infiltration of inflammatory monocytes, activation of T cells in the brain, and significant blood brain barrier disruption. These neuroinflammatory events were induced by TRMs, as depletion of peripheral T cells or blocking T cell trafficking using FTY720 did not change the neuroinflammatory course. Reactivation of antigen-specific TRMs in the brain also induced profound lymphopenia within the blood compartment. We have therefore determined that antigen-specific TRMs can induce significant neuroinflammation, neuropathology, and peripheral immune suppression. Importantly, understanding functions of brain TRMs is crucial in investigating their role in neurodegenerative disorders, CNS cancers, and long-term complications associated with viral infections including COVID-19. Graphical AbstractHealthy brain harbors populations of resident memory T cells (TRM). These TRM cells rapidly proliferate in response to CNS insults of various origins. Following clearance of the insult, populations of TRM cells in the brain decline, but an antigen-specific TRM subset remains within the brain. Antigen-specific reactivation of brain TRMs mediates neuroinflammatory sequalae involving activation and blasting of resident T cells, infiltration of inflammatory monocytes and blood brain barrier disruption. Severe neuroinflammation within the brain following antigen-specific TRM reactivation is concurrent with profound lymphopenia within the blood compartment. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=132 SRC="FIGDIR/small/487707v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@a22867org.highwire.dtl.DTLVardef@a90e0org.highwire.dtl.DTLVardef@1ad904eorg.highwire.dtl.DTLVardef@1dd281c_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2021

Microglia and perivascular macrophages act as antigen presenting cells to promote CD8 T cell infiltration of the brain

CD8 T cell infiltration of the central nervous system (CNS) is necessary for host protection but contributes to neuropathology. Antigen presenting cells (APCs) situated at CNS borders are thought to mediate T cell entry into the parenchyma during neuroinflammation. The identity of the CNS-resident APC that presents antigen via major histocompatibility complex (MHC) class I to CD8 T cells is unknown. Herein, we characterize MHC class I expression in the naive and virally infected brain and identify microglia and macrophages (CNS-myeloid cells) as APCs that upregulate H-2Kb and H-2Db upon infection. Conditional ablation of H-2Kb and H-2Db from CNS-myeloid cells allowed us to determine that antigen presentation via H-2Db, but not H-2Kb, was required for CNS immune infiltration during Theilers murine encephalomyelitis virus (TMEV) infection and drives brain atrophy as a consequence of infection. These results demonstrate that CNS-myeloid cells are key APCs mediating CD8 T cell brain infiltration.

immunology↗

bioRxiv2020

Severe and multifaceted systemic immunosuppression caused by experimental cancers of the central nervous system requires release of non-steroid soluble mediators

Immunosuppression of unknown etiology is a hallmark feature of glioblastoma (GBM) and is characterized by decreased CD4 T cell counts and down regulation of MHC class II expression on peripheral blood monocytes in patients. This immunosuppression is a critical barrier to the successful development of immunotherapies for GBM. We recapitulated the immunosuppression observed in GBM patients in the C57BL/6 mouse and investigated the etiology of low CD4 T cell counts. We determined that thymic involution was a hallmark feature of immunosuppression in three distinct models of CNS cancer, including mice harboring GL261 glioma, B16 melanoma, and in a spontaneous model of Diffuse Intrinsic Pontine Glioma (DIPG). In addition to thymic involution, we determined that tumor growth in the brain induced significant splenic involution, reductions in peripheral T cells, reduced MHC class II expression on hematopoietic cells, and a modest increase in bone marrow resident CD4 T cells with a naive phenotype. Using parabiosis we report that thymic involution, declines in peripheral T cell counts, and reduced MHC class II expression levels were mediated through circulating blood-derived factors. Conversely, T cell sequestration in the bone marrow was not governed through circulating factors. Serum isolated from glioma-bearing mice potently inhibited proliferation and functions of T cells both in vitro and in vivo. Interestingly, the factor responsible for immunosuppression in serum is nonsteroidal and of high molecular weight. Through further analysis of neurological disease models, we determined that the aforementioned immunosuppression was not unique to cancer itself, but rather occurs in response to CNS injury. Noncancerous acute neurological insults also induced significant thymic involution and rendered serum immunosuppressive. Both thymic involution and serum-derived immunosuppression were reversible upon clearance of brain insults. These findings demonstrate that CNS cancers cause multifaceted immunosuppression and pinpoint circulating factors as a target of intervention to restore immunity. Short SummaryCNS cancers and other brain-injuries suppress immunity through release of non-steroid soluble factors that disrupt immune homeostasis and dampen responses of the peripheral immune system. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/006825v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@14e90c2org.highwire.dtl.DTLVardef@101de5corg.highwire.dtl.DTLVardef@1ad8534org.highwire.dtl.DTLVardef@1041fef_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract C_FIG

immunology↗

bioRxiv2019

Conditional silencing of H-2Db class I molecule expression on dendritic cells modulates the protective and pathogenic kinetics of virus-antigen specific CD8 T cell responses during Theiler’s Virus infection

Theilers murine encephalomyelitis virus (TMEV) infection of the central nervous system is rapidly cleared in C57BL/6 mice by an anti-viral CD8 T cell response restricted by the MHC class I molecule, H-2Db. While the CD8 T cell response against neurotropic viruses is well characterized, the identity and function of the antigen presenting cell(s) involved in this process is(are) less well defined. To address this gap in knowledge, we developed a novel C57BL/6 H-2Db conditional knockout mouse that expresses an H-2Db transgene in which the transmembrane domain locus is flanked by LoxP sites. We crossed these H-2Db LoxP mice with MHC class I-deficient mice expressing Cre-recombinase under either the CD11c or LysM promoter in order to silence H-2Db restricted antigen presentation predominantly in dendritic cells or macrophages, respectively. Upon challenge with intracranial TMEV infection, we observe that CD11c+ APCs are critical for early priming of CD8 T cells against the immunodominant TMEV peptide VP2121-130 presented in the context of the H-2Db molecule. This stands in stark contrast to later time points post TMEV infection where CD11c+ APCs appear dispensable for the activation of antigen-specific T cells; the functionality of these late-arising antiviral CD8 T cells is reflected in the restoration of viral control at later time points. These late-arising CD8 T cells also retain their capacity to induce blood-brain barrier disruption. In contrast, when H-2Db restricted antigen presentation was selectively silenced in LysM+ APCs there was no overt impact on the priming of Db:VP2121-130 epitope-specific CD8 T cells, although a modest reduction in immune cell entry into the CNS was observed. This work establishes a model system which enables critical dissection of MHC class I restricted antigen presentation to T cells, revealing cell specific and temporal features involved in the generation of antiviral CD8 T cell responses. Employing this novel system, we established CD11c+ cells as a pivotal driver of acute, but not later-arising, antiviral CD8 T cell responses against the TMEV immunodominant epitope VP2121-130, with functional implications both for T cell-mediated viral control and immunopathology.

immunology↗