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Schreiner, D.

Publications and source records attributed to Schreiner, D..

9 recordsLinked to original sources

Comparative analysis of BCG vaccination routes in mice reveals preferential reprogramming of pulmonary macrophages upon mucosal administration.

Bacille Calmette-Guerin (BCG) is the only licensed vaccine against tuberculosis (TB) but provides inconsistent protection against disease. Studies in non-human primates show that intravenous BCG confers superior protection compared to intradermal vaccination, yet how different vaccination routes reprogram lung immunity in mice - the primary model for mechanistic studies - remains incompletely defined at single cell or spatial resolution. Moreover, while lung macrophages are key effectors during Mycobacterium tuberculosis infection, most studies have focused on alveolar macrophages, leaving interstitial macrophage responses to vaccination largely unexplored. Here, we define the cellular and spatial immune landscape shaped by three BCG vaccination routes in mice using flow cytometry, single-cell RNA sequencing, and spatial transcriptomics. Comparing intratracheal (IT), intravenous (IV), and subcutaneous (SC) vaccination, we demonstrate that mucosal IT delivery uniquely reprograms interstitial macrophages, establishes spatially organized immune hubs with CD4 T cells, and provides superior protection against infectious challenge. These findings identify IM as key mediators of mucosal vaccine-induced protection and provide a framework for the rational optimization of vaccines against respiratory pathogens.

immunology↗

HIF-1α+ CD4 T cells coordinate a tissue resident immune cell network in the lung

A deeper understanding of how tissue localized immune cells arise and function is critical for developing mucosal vaccines. Currently, there are no murine models that specifically target tissue T cells while leaving their lymphoid counterparts untouched. Here we leverage the observation that during influenza infection, HIF-1 regulatory activity is higher in the lung compared to lymph node CD4 T cells. Inducible deletion of Hif1a in CD4 T cells, at the onset of its activity in the lung, reduces the tissue resident T cell compartment with minimal impact on peripheral immunity. HIF-1-active CD4 T cells occupy the border of tertiary lymphoid structures, where they coordinate an IL-21-dependent network of spatially co-localized immune cells including macrophages, NK cells and IgA+ B cells. A similar HIF-1-dependent network is engaged in a lung adenocarcinoma model, highlighting a broader role for HIF-1+ CD4 T cells in integrating protective immunity during infection and cancer.

immunology↗

Proximity labelling reveals the compartmental proteome of murine sensory neurons

IntroductionUnderstanding the molecular architecture of peripheral sensory neurons is critical as we pursue novel drug targets against pain and neuropathy. Sensory neurons in the dorsal root ganglion (DRG) show extensive compartmentalization, thus understanding each compartment - from the peripheral to central terminals - is key to this effort. MethodsTo systematically profile this spatial complexity, we generated a TurboIDfl/fl transgenic mouse line (ROSA26em1(TurboID)Bros), enabling targeted proximity labelling and deep proteomic profiling of DRG neuron compartments via Tg(Advillin-Cre)+. ResultsOur data reveal distinct proteomic signatures across neuronal compartments that reflect specialized neuronal functions. We provide proteomic insights into previously inaccessible nerve terminals both in the periphery (innervating the skin) and in the spinal cord. Further, using a DRG explant model of chemotherapy-induced peripheral neuropathy, we uncover novel and discrete proteome changes, highlighting neuronal vulnerability. ConclusionTogether, our findings provide a unique proteome atlas of the sensory neuron proteome across anatomical domains and demonstrate the utility of proximity labelling proteomics for detecting compartment-specific molecular alterations in a disease model.

neuroscience↗

A ternary Neurexin-T178-PTPR complex represents a core-module of neuronal synapse organization

The organization of cell-cell contacts is fundamental for multi-cellular life and operation of organs. Synapses, prototypic contact sites for neuronal communication, are key to brain function and work over the last decades identified multiple synaptic cell adhesion molecules (sCAMs) that drive their organization. Whether these sCAMs operate independently or in coordination through yet unknown linker proteins remained elusive. Here, we used a systematic large-scale multi-epitope affinity-purification approach combined with quantitative mass spectrometry and immuno-EM to comprehensively map trans-synaptic protein networks in the mouse brain. We discover a presynaptic core-module assembled from the two major sCAM families, Neurexins1-3 and LAR-type receptor protein tyrosine phosphatases (PTPRD,S,F), and the previously uncharacterized tetraspanin proteins T178A, B. These ternary Neurexin-T178-PTPR complexes form through their trans-membrane domains and assemble during biogenesis in the ER. Loss of T178B results in module dissociation, strong reduction of LAR-PTPRs and re-distribution of synaptic Neurexins. At synapses, the Neurexin-T178-PTPR module recruits stable and extended trans-synaptic protein networks with defined pre- and post-synaptic partners and secreted extracellular linkers. The network architecture robustly interlinks the distinct functional modules/machineries of the presynaptic active zone and establishes tight associations with XKR-type lipid scramblases and postsynaptic GABAergic and glutamatergic neurotransmitter receptors. Our data identify a universal presynaptic core-module for synaptic adhesion and trans-synaptic signaling in the mammalian brain.

neuroscience↗

Dilated cardiomyopathy-associated RNA Binding Motif Protein 20 regulates long pre-mRNAs in neurons

Precise coordination of molecular programs and neuronal growth govern the formation, maintenance, and adaptation of neuronal circuits. RNA metabolism has emerged as a key regulatory node of neural development and nervous system pathologies. To uncover cell-type-specific RNA regulators, we systematically investigated expression of RNA recognition motif-containing proteins in the mouse neocortex. Surprisingly, we found RBM20, an alternative splicing regulator associated with dilated cardiomyopathy, to be expressed in cortical parvalbumin interneurons and mitral cells of the olfactory bulb. Genome-wide mapping of RBM20 target mRNAs revealed that neuronal RBM20 binds pre-mRNAs in distal intronic regions. Loss of neuronal RBM20 has only modest impact on alternative splice isoforms but results in a significant reduction in an array of mature mRNAs in the neuronal cytoplasm. This phenotype is particularly pronounced for genes with long introns that encode synaptic proteins. We hypothesize that RBM20 ensures fidelity of pre-mRNA splicing by suppressing non-productive splicing events in long neuronal genes. This work highlights a common requirement for RBM20-dependent transcriptome regulation in cardiomyocytes and neurons and demonstrates that a major genetic risk factor of heart disease impacts neuronal gene expression.

neuroscience↗

Control of neuronal excitation-inhibition balance by BMP-SMAD1 signaling

Throughout life, neuronal networks in the mammalian neocortex maintain a balance of excitation and inhibition which is essential for neuronal computation. Deviations from a balanced state have been linked to neurodevelopmental disorders and severe disruptions result in epilepsy. To maintain balance, neuronal microcircuits composed of excitatory and inhibitory neurons sense alterations in neural activity and adjust neuronal connectivity and function. Here, we identified a signaling pathway in the adult mouse neocortex that is activated in response to elevated neuronal network activity. Over-activation of excitatory neurons is signaled to the network through the elevation of BMP2, a growth factor well-known for its role as morphogen in embryonic development. BMP2 acts on parvalbumin-expressing (PV) interneurons through the transcription factor SMAD1, which controls an array of glutamatergic synapse proteins and components of peri-neuronal nets. PV interneuron-specific disruption of BMP2-SMAD1 signaling is accompanied by a loss of PV cell glutamatergic innervation, underdeveloped peri-neuronal nets, and decreased excitability. Ultimately, this impairment of PV interneuron functional recruitment disrupts cortical excitation - inhibition balance with mice exhibiting spontaneous epileptic seizures. Our findings suggest that developmental morphogen signaling is re-purposed to stabilize cortical networks in the adult mammalian brain.

neuroscience↗

Trans-cellular control of synapse properties by a cell type-specific splicing regulator

The recognition of synaptic partners and specification of synaptic properties are fundamental for the function of neuronal circuits. Terminal selector transcription factors coordinate the expression of terminal gene batteries that specify cell type-specific properties. Moreover, pan-neuronal alternative splicing regulators have been implicated in directing neuronal differentiation. However, the cellular logic of how splicing regulators instruct specific synaptic properties remains poorly understood. Here, we combine genome-wide mapping of mRNA targets and cell type-specific loss-of-function studies to uncover the contribution of the nuclear RNA binding protein SLM2 to hippocampal synapse specification. Focusing on hippocampal pyramidal cells and SST-positive GABAergic interneurons, we find that SLM2 preferentially binds and regulates alternative splicing of transcripts encoding synaptic proteins, thereby generating cell type-specific isoforms. In the absence of SLM2, cell type-specification, differentiation, and viability are unaltered and neuronal populations exhibit normal intrinsic properties. By contrast, cell type-specific loss of SLM2 results in highly selective, non-cell autonomous synaptic phenotypes, altered synaptic transmission, and associated defects in a hippocampus-dependent memory task. Thus, alternative splicing provides a critical layer of gene regulation that instructs specification of neuronal connectivity in a trans-synaptic manner.

neuroscience↗

Successful IL-12 cancer immunotherapy requires NK cell-derived CCL5 for anti-tumor DC-T cell crosstalk

T cell-directed cancer immunotherapy often fails to generate lasting tumor control. Harnessing additional effectors of the immune response against tumors may strengthen the clinical benefit of immunotherapies. Here, we demonstrate that therapeutic targeting of the IFN{gamma}-IL-12 pathway relies on the ability of a population of tissue-resident NK (trNK) cells to orchestrate an anti-tumor microenvironment. Particularly, utilizing an engineered adenoviral platform, we show that paracrine IL-12 enhances functional DC-CD8 T cell interactions to generate adaptive anti-tumor immunity. This effect depends on the abundance of trNK cells and specifically their capacity to produce the cDC1-chemoattractant CCL5. Failure to respond to IL-12 and other IFN{gamma}-inducing therapies such as immune checkpoint blockade in tumors with low trNK cell infiltration could be overcome by intra-tumoral delivery of CCL5. Our findings reveal a novel barrier for T cell-focused therapies and offer mechanistic insights into how T cell-NK cell-DC crosstalk can be enhanced to promote anti-tumor immunity and overcome resistance. SignificanceWe identified the lack of CCL5-producing, tissue-resident NK (trNK) cells as a barrier to T cell-focused therapies. While IL-12 induces anti-tumoral DC-T cell crosstalk in trNK cellrich tumors, resistance to IL-12 or anti-PD-1 in trNK cellpoor tumors can be overcome by the additional delivery of CCL5.

immunology↗

Redefining CD4 T cell residency: Helper T cells orchestrate protective humoral immunity in the lung

Influenza is a severe and acute respiratory pathogen, and a significant cause for morbidity, particularly in young children and the elderly. Following influenza infection, clonally expanded T cells take up permanent residence in the lung where they are poised to rapidly respond to challenge infection. The non-circulating status of these tissue resident memory (TRM) cells makes them an attractive target for vaccination. While many studies have characterized CD8 TRM cells, less is known about the heterogeneity and protective capacity of CD4 TRM cells. Here we characterized the dynamics and transcriptional regulation of lung resident CD4 T cells to define a non-lymphoid signature that removes the bias created by the prevalence of Th1 helper cells during viral infection. We identified a novel population of long-lived T resident helper (TRH) cells that requires intrinsic Bcl6 expression for their differentiation. Although TRH cells also depend on B cells, they are generated independently of T follicular helper effector cells in the lymph node. In contrast to lung resident Th1 cells, TRH cells are tightly co-localized with B cells in inducible Bronchus Associated Lymphoid Tissue (iBALT). Deletion of Bcl6 in CD4 T cells prior to heterotypic challenge infection results in redistribution of CD4 T cells outside of iBALT areas and impaired local antibody production. These data highlight lung iBALT as a niche for the homeostasis and survival of TRH cells, and further suggest that vaccination strategies to selectively induce TRH cells can improve protective immunity in the tissue.

immunology↗