Biology subjects

Klein, E.

Publications and source records attributed to Klein, E..

At least 19 recordsLinked to original sources

bioRxiv2026

Van der Waals interactions mediate the enantiomeric substrate preference of the CTP:phosphoglycerate cytidylyltransferase CpgD

Caulobacter crescentus is a gram-negative bacterium that produces the anionic sphingolipid ceramide diphosphoglycerate that can substitute for the lipopolysaccharide component of the outer membrane. ccna_01210 is a gene in the operon for ceramide diphosphoglycerate synthesis and encodes for the enzyme, CpgD. CpgD is a magnesium-dependent CTP:phosphoglycerate cytidylyltransferase that catalyzes the synthesis of CDP-glycerate, and a pyrophosphate byproduct. CpgD displays substrate specificity for the nucleotide CTP and a preference for 2-phospho-D-glycerate over other phosphoglycerate enantiomers and isomers. Here, we present five high resolution structures for CpgD in various catalytic states that rationalize the specificity and preference of CpgD for its two substrates. This includes structures of apo CpgD, a CpgD-CTP-Mg2+ ternary complex, and three CpgD-CDP-glycerate-pyrophosphate-Mg2+ product bound complexes. The structures reveal CpgD nucleotide specificity is mediated by favorable hydrogen bonding interactions with the cytosine nucleobase of CTP, while the preference for 2-phospho-D-glycerate occurs due to favorable van der Waals interactions with the 2D enantiomer and unfavorable steric clashes with the 2L enantiomer. A catalytic mechanism involving a pentacoordinate transition state is proposed based on the observed stereochemical inversion of the -phosphate in the substrate CTP in comparison to the -phosphate of the product CDP-glycerate. Overall, this provides insights into the catalytic mechanism, nucleotide specificity, and enantiomeric substrate preference of the cytidylyltransferase CpgD that participates in a unique pathway of bacterial sphingolipid synthesis.

biochemistry↗

bioRxiv2026

Multichannel optical cochlear implants enable spectrally distinct auditory activity

When hearing fails, cochlear implants (CIs) restore auditory perception. Yet, coding of spectral information remains a bottleneck because each electrode broadly activates the auditory nerve. As light can be more conveniently confined, optical (o)CIs present an alternative. Here, we combined expression of the potent channelrhodopsin ChReef in spiral ganglion neurons (SGNs) with oCIs comprising 5-10 green LEDs in gerbils. This combination enabled systematic comparison of encoding intensity and spectral information by individual oCI channels to acoustic and electrical stimulation within a translationally feasible energy range. Recordings from the inferior colliculus (ICC) showed that ChReef aligned SGN light sensitivity with LED radiant fluxes: ICC activity had thresholds <200 nJ and reached a maximum equivalent to that achieved with 51 dB SPL pure tones. Multichannel oCIs enabled tonotopically ordered, spectrally distinct stimulation that more closely resembled acoustic stimulation than did electrical stimulation. Some LEDs elicited multiple spectral peaks at higher intensities. Linear discriminant analysis of ICC activity indicated improved channel discriminability for optical over electrical stimulation. In summary, ,micro-joule oCI-stimulation achieves improved spectral resolution over state-of-the-art electrical stimulation.

neuroscience↗

bioRxiv2026

SIV infection disrupts the spatial cellular and communication networks of pulmonary granulomas during SIV/Mtb co-infection

Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) is the leading infectious cause of death globally. Despite wide use of antiretroviral therapy (ART) by people living with HIV, the risk of TB remains increased. To understand immune interactions within lung granulomas, we compared spatial transcriptomics of Mtb and simian immunodeficiency virus (SIV) in co-infected macaques with or without ART as a model for HIV/Mtb co-infection. Spatially differentiated transcriptional profiles were observed in Mtb-only granulomas, with myeloid cells enriched in metabolic/antimicrobial pathways within the inner ring and T cell costimulatory/activation pathways enriched in the outer ring. These spatially distinct patterns were lost in SIV/Mtb granulomas with higher enrichment in type I IFN pathways compared to Mtb-only granulomas. SIV/ART/Mtb granulomas had an intermediate transcriptional pattern without restoration to Mtb-only granulomas, despite a lack of viral replication. Cell-cell communication was reduced among SIV/Mtb co-infected groups. These data suggest that HIV disrupts spatially organized immune functions of granulomas, which are not fully restored by ART.

immunology↗

bioRxiv2026

Circulating immune profiling reveals impaired monocyte states and trajectories driving immunosuppression in glioblastoma

Glioblastoma (GBM) is an aggressive and lethal brain tumor marked by profound local and systemic immune dysfunction. Yet, the diagnostic and therapeutic relevance of peripheral impairments remains undefined. To clinically dissect their underlying mechanisms and pathological implications, we combined mass and flow cytometry with single-cell RNA-sequencing of peripheral blood mononuclear cells from GBM patients and healthy donors. GBM blood profiles were characterized by heterogeneous changes in classical monocytes, encompassing expanded, reduced and unchanged subsets, presenting distinct functional states, including antigen-presenting, interferon and metabolic subsets. Additional adaptations included myeloid-derived suppressor cell (MDSC) expansion and loss of non-classical monocytes. Trajectory analyses positioned MDSCs as an intermediate state, in continuum with the metabolic subset. Single-cell RNA-sequencing further showed antigen-presenting monocyte propensity to differentiate into tumor-associated macrophages. Circulating monocytes shared a "GBM-classical monocytic signature" exhibiting low MHC class II expression, altered cell-cell communication and increased anti-inflammatory mediators, such as IL1R2 and CD163. Lastly, lymphocyte alterations included decreased proportions of CD4+ T, natural killer (NK) and CD56+ T cells, retaining relatively conserved activation profiles, exemplified by up-regulation of alarmins S100A8/S100A9. These findings map systemic immune reprogramming in GBM, suggesting new avenues for non-invasive biomarker discovery and therapeutic strategies to restore anti-tumor immunity.

cancer biology↗

bioRxiv2025

Humanized glioblastoma patient-derived orthotopic xenografts recreate a locally immunosuppressed human immune ecosystem amenable to immunotherapeutic modulation

Immune-based strategies have so far failed to demonstrate clinical benefit in glioblastoma (GBM), largely due to the profound immunosuppressive tumor microenvironment (TME). To achieve more predictive preclinical insights, advanced in vivo models that faithfully recapitulate the human brain immune landscape are urgently needed. Here, we established GBM patient-derived orthotopic xenografts (PDOXs) across diverse mouse strains, including humanized models. Humanization was achieved through transplantation of CD34+ hematopoietic stem cells (HU-CD34+) or peripheral blood mononuclear cells (HU-PBMC). Both models successfully reconstituted human T-cells systemically, with stronger engraftment in HU-CD34+ mice. We observed selective infiltration and spatial organization to intracranial GBM tumors, including exhausted, memory-like, and regulatory CD4+ T-cell phenotypes, TIM-3+ immunosuppressive-like myeloid cells and intratumoral B cells. Mouse microglia-derived tumor-associated macrophages (TAMs) remained the dominant immunosuppressive immune population. Anti-PD-1 therapy, but not anti-GITR, modestly modulated the infiltration dynamics, demonstrating the susceptibility of the reconstructed adaptive immunity to immunotherapeutic intervention. These findings position humanized GBM PDOXs as a relevant preclinical platform to interrogate tumor-immune interactions and evaluate immunotherapeutic strategies in a human context. Key pointsO_LIGBM PDOXs developed in HU-CD34+ and HU-PBMC mice faithfully reconstitute systemic and local human adaptive immunity. C_LIO_LIHuman immune components undergo selective infiltration, spatial organization and transition towards exhausted CD4+ T-cells and immunosuppressive CD11c+ myeloid cells. C_LIO_LIAnti-PD-1, but not anti-GITR, locally promote human immune infiltration into intracranial GBM tumors, while sparing systemic compartments. C_LIO_LIHumanized GBM PDOXs provide a powerful preclinical platform to test novel immunotherapeutic strategies. C_LI Study importanceImmune checkpoint blockade has shown limited efficacy in GBM, reflecting the highly immunosuppressive and lymphocyte-poor nature of the TME. Conventional syngeneic and GEMM models fail to recapitulate these features, contributing to the translational disconnect between preclinical success and clinical failure. Humanized mice provide a solution to interrogate human-specific immunity in vivo, but their use in GBM has remained limited. Here, we provide the first comparison of GBM PDOX modeling in two complementary modes of humanization based on CD34+ HSCs and PBMCs. We systematically profile systemic and intratumoral compartments, showing that these models faithfully reconstitute human adaptive immunity and capture the interplay with the murine brain TME. Furthermore, we demonstrate clinically-relevant responses upon treatment with checkpoint antibodies targeting PD-1 and GITR, showing modulation of human immune subsets without altering murine TAM immunosuppression, underscoring the translational value of the system. This study establishes humanized GBM PDOXs as a versatile platform for dissecting tumor-immune interactions in the brain and for preclinical evaluation and development of novel immunotherapies. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/689484v2_ufig1.gif" ALT="Figure 1"> View larger version (74K): org.highwire.dtl.DTLVardef@1b684e1org.highwire.dtl.DTLVardef@1cdfbbdorg.highwire.dtl.DTLVardef@4a570borg.highwire.dtl.DTLVardef@98b112_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2025

Integrative multi-omics combined with functional pharmacological profiling in patient-derived organoids identifies personalized therapeutic vulnerabilities of adult high-grade gliomas

BackgroundPrecision medicine has transformed cancer treatment by tailoring therapies to specific molecular aberrations. Integrating high-resolution multi-omics with high-throughput functional profiling in patient-derived organoids of-fers a powerful strategy to further refine patient stratification. While (epi)genetic profiling has drastically improved the classification in diffuse adult gliomas, these advances have not yet translated into effective therapeutic interventions and precision medicine approaches remain to be established. Material and MethodsWe investigated a panel of 48 patient-derived organoid and orthotopic xenograft models of adult high-grade gliomas, comprehensively characterized at genomic, epigenomic and transcriptomic levels. A functional drug screen was performed on 27 organoid models using a 202-compound library targeting cancer-related pathways and epigenetic regulators. Unsupervised multi-omics factor analysis was employed to identify patient-specific therapeutic vulnerabilities. Validation included dose-dependent drug efficacy assessments, as well as biomarker assessment in patient tumors across molecular subgroups. ResultsMulti-omics analysis revealed a broad spectrum of molecular profiles capturing the genetic, epigenetic, and transcriptomic diversity of high-grade gliomas. Multi-omics factor analysis, integrating multi-omics and drug response profiles, identified distinct subgroups associated with IDH1 mutation and MYCN amplification. IDH1 mutant grade 4 astrocytomas showed selective sensitivity to histone deacetylase 3 inhibitors, while a MYCN-amplified glioblastoma responded preferentially to histone methyltransferase inhibitors. The differential drug responses were linked to specific (epi)genetic and transcriptomic biomarkers. While other glioblastomas exhibited heterogeneous treatment responses, no robust biomarker-defined responder subgroups were identified. ConclusionOur findings highlight the value of integrating multi-omics and functional profiling to inform precision medicine strategies. This approach enables the stratification of distinct patient subgroups in preclinical models, paving the way for tailored therapeutic interventions. While we observed distinct pharmacogenomic profiles in IDH1 mutant grade 4 astrocytomas and a MYCN-amplified glioblastoma, implementing precision medicine in other glioblastoma subtypes remains a substantial challenge. Key pointsO_LIIntegrating drug screening in a panel of patient-derived organoids with multi-omics enables pharmacogenomic profiling in adult diffuse high-grade gliomas C_LIO_LIIDH1 mutant grade 4 astrocytomas are sensitive to histone deacetylase 3 inhibitors C_LIO_LIMYCN-amplified glioblastoma exhibits distinct DNA methylation pattern and drug responses C_LI Study importanceTo date, attempts to develop effective precision medicine in adult high-grade gliomas failed. Here, we provide a preclinical framework for identifying personalized therapeutic by integrating multi-omics profiling with functional drug screening in patient-derived organoids. We show that IDH1 mutant high-grade astrocytomas present distinct therapeutic vulnerabilities compared to glioblastomas, linked to sensitivity to histone deacetylase 3 inhibitors. Within glioblastomas, we identified a distinct MYCN-amplified tumor, sensitive to histone methyltransferase inhibitors. Applying pharmacogenomic approaches using novel drug libraries holds promise for uncovering additional clinically relevant patient subgroups in the future. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/675145v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@12c04f9org.highwire.dtl.DTLVardef@fa8872org.highwire.dtl.DTLVardef@141de6org.highwire.dtl.DTLVardef@b72086_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2025

Antiretroviral treatment does not prevent extrapulmonary tuberculosis during SIV/Mtb co-infection in macaques

Co-infection with both HIV and M. tuberculosis (Mtb) results in disseminated tuberculosis (TB) and accelerated progression of HIV. Despite greater access to antiretroviral treatment (ART), it remains unclear whether suppression of HIV replication protects against severe Mtb infection. Here, using a macaque model of SIV/Mtb coinfection, we investigated whether treatment of SIV infection with ART influenced control of a subsequent Mtb challenge compared to SIV infected macaques who were not treated with ART. Using a macaque model of simian immunodeficiency virus (SIV)-Mtb co-infection, macaques were first infected with SIVB670, SIVB670 with ART, or saline followed by a low-dose Mtb inoculation with serial clinical, microbiological, PET CT imaging, and immunologic assessments. At necropsy, gross pathology, viremia, bacterial burden, and immunologic parameters were compared. SIV-TB animals had greater gross pathology and total bacterial burden than TB only and SIV/ART/TB groups. However, despite normal blood CD4 counts and undetectable SIV RNA, SIV/ART/TB macaques showed similar clinical parameters and extrapulmonary involvement as SIV/TB animals. Analysis of barcoded-Mtb suggests ART control of SIV replication does not prevent Mtb extrapulmonary dissemination. These data indicate that people living with HIV on ART remain at high risk of bacterial dissemination and extrapulmonary TB disease, particularly when methods to identify extrapulmonary disease are inconsistent. This highlights the importance of understanding the mechanism of extrapulmonary spread and disease severity in HIV/TB co-infected individuals.

immunology↗

bioRxiv2025

Emergence of an Antigenically Drifted and Reassorted Influenza B Virus at the end of the 2024-25 Influenza Season

Influenza B virus (IBV) is a significant contributor to annual and severe cases of influenza, particularly in the young and elderly. Late in the 2024-25 Northern Hemisphere influenza season, a surge of IBV cases were identified in the Johns Hopkins Hospital Systems. The IBV responsible for the surge, C.3.1/re, was a clade C.3 virus that had reassorted with clade C.5.1 viruses and acquired the D197N mutation in hemagglutinin restoring a putative N-linked glycan predicted to mask a key neutralizing antibody epitope. The C.3.1/re viruses preferentially infected children but showed no significant change in disease severity. C.3.1/re viruses were poorly neutralized by pre- and post- influenza vaccination serum in a human cohort. Removal of the glycan at residue 197 restored neutralizing antibody recognition. The C.3.1/re IBV genotype that emerged late in the 2024-25 influenza season was antigenically mismatched with IBV vaccine strains for the 2025 and 2026 Southern hemisphere, as well as the 2025-26 Northern Hemisphere influenza seasons. While the 2026-27 Northern Hemisphere vaccine strain is a C.3.1/re, the egg adapted isolate selected (B/Tokyo/EIS13-175/2025) lacks the 197 glycosylation which is predicted to have poor recognition with circulating IBV clades. Phylogenetic analysis of currently circulating IBVs shows a diversification of circulating C.3 clades with multiple reassortment events between C.3 and C.5 clades in addition to independent acquisitions of D197N mutations, suggesting IBV is going through a period of significant antigenic and genetic expansion. IMPORTANCEInfluenza B viruses are undergoing a period of antigenic and genetic expansion, with several reassorted viruses emerging that also contain point mutations in key hemagglutinin antigenic sites proximal to the receptor binding domain. This has important impacts on vaccine strain choice, as only one IBV component is included in current influenza vaccines. We demonstrate a significant shift in the demographics of IBV infected individuals with the emergence of the antigenically drifted and reassorted IBV C.3.1/re. Furthermore, we show that 197 glycosylation of hemagglutinin is critical for C.3.1/re antigenic drift and we document several emergent C.3 reassortments encoding the D197N mutation. With the IBV vaccine component for the Northern Hemisphere 2026-27 season having lost a key N-linked glycan on the hemagglutinin protein, and multiple independent emergences of antigenically drifted and reassorted viruses, attention to IBV infections should be increased in the upcoming Southern and Northern hemisphere influenza seasons.

microbiology↗

bioRxiv2025

Protection against reinfection with Mycobacterium tuberculosis extends across heterologous Mtb lineages

Immunological memory elicited either through previous or ongoing M. tuberculosis (Mtb) infection provides a critical mechanism by which hosts protect against re-infection and disease progression upon Mtb re-exposure. Conversely, the uneven competition between distinct Mtb strains suggest certain bacterial clades have enhanced ability to spread across communities and circulate globally, potentially by evading memory responses gained by prior infection with genomically different strains. To address whether memory responses induced by one strain can protect against a genetically distinct strain, we conducted a heterologous reinfection study in cynomolgus macaques involving primary infection by a Lineage 4 Erdman Mtb strain and subsequent re-challenge by a Lineage 2 strain, HT-L2. Recent epidemiologic studies have shown that the clade to which HT-L2 belongs has been spreading successfully over the last decade in Lima, Peru. Here, through microbiologic, PET-CT imaging and sequencing of Mtb genomic barcodes, we show that reinfected animals developed fewer lung lesions and controlled both pulmonary and disseminated forms of infection better than naive animals without prior exposure to Mtb. Our data support that protection against reinfection is not limited by Mtb lineage, providing optimism that vaccines can be effective across populations and geographic locations.

immunology↗

bioRxiv2025

Social stress causes gut dysbiosis in male, female, and aggressor mice

BACKGROUNDPsychological stress causes gut dysbiosis, which is associated with adverse effects on physical and mental health in humans and mice. Understanding the specific taxa of gut bacteria changed by stress, and whether stress differentially alters their relative abundance in males and females, has important implications for stress-related disorders. METHODSWe modeled individual differences in resilience or susceptibility using the chronic social defeats stress (CSDS) paradigm. Here, C57BL/6 mice are exposed to a novel retired breeder CD-1 aggressor for 10 minutes per day for 10 days. In this paradigm, resilient and susceptible subpopulations can be identified using the social interaction paradigm following CSDS. Fecal samples were collected following Day 1 and Day 10 of CSDS. 16S ribosomal RNA sequencing was used to identify the relative abundance of 200 bacteria species. We analyzed group differences in phyla, genera, and species in CD-1 aggressors along with resilient, susceptible, and non-stressed control male and female C57/BL/6 intruders. RESULTSStress reduced microbiome diversity and caused gut dysbiosis in all groups, including aggressors. CSDS altered the relative abundance of every phylum detected. We report genera whose relative abundance was changed by CSDS or sex. Increases in the relative abundance of an uncultured Ruminococcus species on day 1 predicted aspects of social behavior, with a stronger correlation in stressed females compared to males. CONCLUSIONSCSDS causes gut dysbiosis in male and female mice, with generally similar effects in mice that behave differently following stress. ONE SENTENCE SUMMARYWe report the effects of chronic social defeat stress on gut dysbiosis in aggressors, non-defeated controls, and male and female mice that are either resilient or susceptible to the adverse effects of stress. IN THIS ISSUE SUMMARYWe characterize changes to the gut microbiome of male and female mice that are either resilient or susceptible to the adverse effects of social stress. Stress shifted the relative abundance of broad and specific taxa, which sometimes differed between males and females. We found that the abundance of an uncultured Ruminococcus species on day 1 predicted social behavior following stress. This effect was primarily observed in females.

microbiology↗

bioRxiv2025

Characterizing PET CT patterns and bacterial dissemination features of tuberculosis relapse in the macaque model

Tuberculosis (TB) relapse after appropriate drug treatment is poorly understood but critical to developing shorter treatment regimens. Using a cynomolgus macaque model of human TB, macaques with active TB disease were treated with a short course of isoniazid and rifampin and subsequently infected with SIV. Serial clinical, microbiologic, immunologic and position emission and computed tomography (PET CT) assessments were performed to identify risk factors of relapse. Of the 12 animals, eight developed radiologically defined relapse including four that had clinical and/or microbiologic signs. Greater gross pathology and bacterial burden were observed in relapse animals. PET CT characteristics before, during, and at the end of treatment were similar amongst relapse and non-relapse animals. We show that complete sterilization or very low Mtb burden is protective against SIV-induced TB relapse but cannot be predicted by PET CT. Using bar-coded M. tuberculosis, we found that Mtb dissemination during relapse originated from both lung and thoracic lymph nodes, underscoring the importance of lymph nodes as a reservoir. By matching bar-coded Mtb and serial PET CT, we also demonstrate that not every site of persistent Mtb growth after drug treatment is capable of dissemination and relapse, underscoring the complex nature of drug treatment and relapse.

immunology↗

bioRxiv2025

The immunometabolic topography of tuberculosis granulomas governs cellular organization and bacterial control

Despite being heavily infiltrated by immune cells, tuberculosis (TB) granulomas often subvert the host response to Mycobacterium tuberculosis (Mtb) infection and support bacterial persistence. We previously discovered that human TB granulomas are enriched for immunosuppressive factors typically associated with tumor-immune evasion, raising the intriguing possibility that they promote tolerance to infection. In this study, our goal was to identify the prime drivers for establishing this tolerogenic niche and to determine if the magnitude of this response correlates with bacterial persistence. To do this, we conducted a multimodal spatial analysis of 52 granulomas from 16 non-human primates (NHP) who were infected with low dose Mtb for 9-12 weeks. Notably, each granulomas bacterial burden was individually quantified allowing us to directly ask how granuloma spatial structure and function relate to infection control. We found that a universal feature of TB granulomas was partitioning of the myeloid core into two distinct metabolic environments, one of which is hypoxic. This hypoxic environment associated with pathologic immune cell states, dysfunctional cellular organization of the granuloma, and a near-complete blockade of lymphocyte infiltration that would be required for a successful host response. The extent of these hypoxia-associated features correlated with worsened bacterial burden. We conclude that hypoxia governs immune cell state and organization within granulomas and is a potent driver of subverted immunity during TB.

immunology↗

bioRxiv2024

CD4 T cells and CD8α+ lymphocytes are necessary for intravenous BCG-induced protection against tuberculosis in macaques

Tuberculosis (TB) is a major cause of morbidity and mortality worldwide despite widespread intradermal (ID) BCG vaccination in newborns. We previously demonstrated that changing the route and dose of BCG vaccination from 5{xi}105 CFU ID to 5{xi}107 CFU intravenous (IV) resulted in prevention of infection and disease in a rigorous, highly susceptible non-human primate model of TB. Identifying the immune mechanisms of protection for IV BCG will facilitate development of more effective vaccines against TB. Here, we depleted select lymphocyte subsets in IV BCG vaccinated macaques prior to Mtb challenge to determine the cell types necessary for that protection. Depletion of CD4 T cells or all CD8 expressing lymphoycytes (both innate and adaptive) resulted in loss of protection in most macaques, concomitant with increased bacterial burdens ([~]4-5 log10 thoracic CFU) and dissemination of infection. In contrast, depletion of only adaptive CD8{beta}+ T cells did not significantly reduce protection against disease. Our results demonstrate that CD4 T cells and innate CD8+ lymphocytes are critical for IV BCG-induced protection, supporting investigation of how eliciting these cells and their functions can improve future TB vaccines. One Sentence SummaryAntibody depletion of lymphocytes in rhesus macques demonstrates key roles for CD4 T cells and innate-like CD8+ lymphocytes in conferring sterilizing immunity against tuberculosis following intravenous BCG vaccination.

immunology↗

bioRxiv2024

Adenoviral Delivery of the CIITA Transgene Induces T-Cell-Mediated Killing in Glioblastoma Organoids

The immunosuppressive nature of the tumor microenvironment poses a significant challenge to effective immunotherapies against glioblastoma (GB). Boosting the immune response is critical for a successful therapy. Here, we adopted a cancer gene therapy approach to induce T-cell mediated killing of the tumor through increased activation of the immune system. Patient-based 3D GB models were infected with a replication-deficient adenovirus (AdV) armed with the Class II Major Histocompatibility Complex (MHC-II) Transactivator CIITA gene (Ad-CIITA). Successful induction of surface MHC-II was achieved in infected GB cell lines and primary human GB organoids. Infection with an AdV carrying a mutant form of CIITA with a single amino acid substitution resulted in cytoplasmic accumulation of CIITA without subsequent MHC-II expression. Co-culture of infected tumor cells with either PBMCs or isolated T-cells led to dramatic breakdown of GB organoids. Intriguingly, both wild-type and mutant Ad-CIITA but not unarmed AdV, triggered immune-mediated tumor cell death in the co-culture system, suggesting an at least partially MHC-II-independent process. We further show that the observed cancer cell killing requires the presence of either CD8+ or CD4+ T-cells and the direct contact between GB and immune cells. We did not however detect evidence of activation of canonical T-cell mediated cell death pathways. While the precise mechanism remains to be determined, these findings highlight the potential of AdV-mediated CIITA delivery to enhance T-cell-mediated immunity against GB.

cancer biology↗

bioRxiv2023

Systemic Sclerosis dermal fibroblast exosomes trigger a Type 1 interferon response in keratinocytes through the TBK/JAK/STAT signalling axis

BackgroundActivation of Type I IFN response has been shown to correlates with disease activity in systemic sclerosis. It is currently unknown whether the tissue-specific Type I IFN activation is a consequence of the response observed in blood or rather its source. Exosomes from SSc fibroblasts were recently shown to activate macrophages in vitro. Here, we aimed to determine the source of Type I IFN signature in SSc skin biopsies and the potential role of exosomes from SSc dermal fibroblasts in the process. MethodsSkin biopsies were obtained from healthy and SSc patients forearms and processed for dermal fibroblasts and keratinocytes. Exosomes were isolated from healthy and SSc dermal fibroblast supernatants by ultracentrifugation and added to human skin keratinocytes. Keratinocyte transcriptome was analysed by RNA-seq analysis. TANK-binding kinase (TBK) and JAK were inhibited using a small molecule inhibitor (GSK8612) and Tofacitinib, respectively. ResultsSSc skin biopsies showed highest levels of Type I IFN response in the epidermal layer. RNA-seq analysis of keratinocytes transcriptome following exposure to dermal fibroblast exosomes showed strong upregulation of IFN signature genes induced by SSc exosomes compared to Healthy control. Inhibition of TBK or JAK activity suppressed the upregulation of the IFN signature induced by SSc exosomes. ConclusionIFN activation of SSc keratinocytes is dependent on their crosstalk with dermal fibroblasts and inducible by extracellular exosomes. Our data indicates that SSc fibroblasts exosomes may carry the signal zero of local Type I IFN activation through activation of pattern recognition receptors upstream of TBK. Key MessagesO_LISSc patient skin exhibit a type 1 IFN signature with keratinocytes being the major source of the signature C_LIO_LICross talk between the fibroblasts and keratinocytes through exosomes may be signal zero for the type 1 IFN signature C_LIO_LIBlocking JAK in the keratinocytes with Tofacitinib disrupts the type 1 IFN signature C_LI

immunology↗

bioRxiv2022

The line bisection bias stems from left-side underawareness, not from right-side hyperattention

It is still a matter of scientific debate whether the line bisection bias frequently observed in patients with spatial neglect is due to attentional underawareness of the left end of the line, attentional hyperattention towards the right end, or a logarithmically compressed perception of the line. To address this question, neglect patients who showed a line bisection bias were administered additional tasks involving horizontal lines (e.g., number line estimation tasks). Their performance was compared to neglect patients not showing a line bisection bias, patients with right hemisphere damage without neglect, and healthy controls. Results indicated that patients with a line bisection bias tended to overestimate lefthand segments when they had to dissect lines into three or four equal parts. This is congruent with both the notions of an underawareness of lefthand segments as well as a logarithmic compression of the line. However, when these patients had to imagine the lines as bounded fraction number lines ranging from 0-1, the results were mixed. When the number lines ranged from 0-10, these patients showed rightward overestimation biases for the numbers 4 and 5. Additionally, all patient groups, but not healthy controls, tended to place number 1 too far to the left and number 9 too far to the right, suggesting a general bias towards endpoints. In sum, this seems more congruent with attentional accounts than a perceptual one. Spatial-numerical associations could be ruled out, as all participants showed a verbal number bisection bias towards smaller numbers (i.e., the left of the mental number line). Therefore, these findings seem to indicate that the line bisection bias is most likely due to underawareness of the left end rather than hyperattention towards the right or a logarithmic perception of the line.

neuroscience↗

bioRxiv2022

T cell transcription factor expression evolves as adaptive immunity matures in granulomas from Mycobacterium tuberculosis-infected cynomolgus macaques

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is a global health concern, yearly resulting in 10 million new cases of active TB. Immunologic investigation of lung granulomas is essential for understanding host control of bacterial replication. We identified and compared the pathological, cellular, and functional differences in granulomas at 4, 12, and 20 weeks post-infection in Chinese cynomolgus macaques. Original granulomas differed in transcription factor expression within adaptive lymphocytes with those at 12 weeks showing higher frequencies of CD8+T-bet+ T cells, while increases in CD4+T-bet+ T cells were observed at 20 weeks post-infection. The appearance of T-bet+ adaptive T cells at 12 and 20 weeks was coincident with a reduction in bacterial burden, suggesting their critical role in Mtb control. This study highlights the evolution of T cell responses within lung granulomas, suggesting that vaccines promoting the development and migration of T-bet+ T cells would enhance mycobacterial control.

immunology↗

bioRxiv2021

Left angular gyrus disconnection impairs multiplication fact retrieval

Arithmetic fact retrieval has been suggested to recruit a left-lateralized network comprising perisylvian language areas, parietal areas such as the angular gyrus (AG), and subcortical structures such as the hippocampus. However, the underlying white matter connectivity of these areas has not been evaluated systematically so far. Using simple multiplication problems, we evaluated how disconnections in parietal brain areas affected arithmetic fact retrieval following stroke. We derived disconnectivity measures by jointly considering data from n=73 patients with acute unilateral lesions in either hemisphere and a white-matter tractography atlas (HCP-842) using the Lesion Quantification Toolbox (LQT). Whole-brain voxel-based analysis indicated a left-hemispheric cluster of white matter fibers connecting the AG and superior temporal areas to be associated with a fact retrieval deficit. Subsequent analyses of direct grey-to-grey matter disconnections revealed that disconnections of additional left-hemispheric areas (e.g., between the superior temporal gyrus and parietal areas) were significantly associated with the observed fact retrieval deficit. Results imply that disconnections of parietal areas (i.e., the AG) with language-related areas (i.e., superior and middle temporal gyri) seem specifically detrimental to arithmetic fact retrieval. This suggests that arithmetic fact retrieval recruits a widespread left-hemispheric network and emphasizes the relevance of white matter connectivity for number processing.

neuroscience↗