Biology subjects

Hauck, S. M.

Publications and source records attributed to Hauck, S. M..

At least 19 recordsLinked to original sources

bioRxiv2026

HIV-1 promotes loss of CD4+ T cell stemness and enrichment of effector-like states via Vpr-mediated TCF7 degradation

HIV-1 Vpr is abundantly packaged into virions and remodels host cells immediately after entry. Here, using high-efficiency HIV-1 infection protocols and unbiased proteomics in primary CD4+ T cells, we identify the T cell fate regulator TCF7 (TCF-1) as a previously unrecognized Vpr target. Virion-delivered Vpr rapidly depleted TCF7 in both resting and activated CD4+ T cells, which was a conserved activity of diverse Vpr proteins. The activity was independent of canonical Vpr substrate engagement but resulted terminally in proteasomal degradation of TCF7. TCF7 suppressed HIV-1 production and Env incorporation, whereas its depletion promoted loss of stem-like properties and differentiation toward effector phenotypes. Accordingly, effector T cell differentiation states are associated with productive HIV-1 infection and reduced TCF7 abundance. Thus, Vpr-mediated TCF7 depletion couples enhanced viral fitness to reprogramming of CD4+ T cell identity, generating permissive differentiated cells while impairing the maintenance of effective antiviral immunity via reduced T cell stemness.

microbiology↗

bioRxiv2026

miR-940 suppresses ferroptosis by controlling expression of key regulatory genes

Ferroptosis is a form of regulated cell death that is characterized by iron-dependent lipid peroxidation. This process is regulated by specific metabolites, the lipid composition of the cells, redox-active iron, and antioxidant mechanisms. Although numerous regulators have been identified over the past decade, exploring other mechanisms, particularly from non-coding genomic regions, can build a thorough understanding of the multifaceted regulatory processes underlying ferroptosis. MicroRNAs (miRNAs) play a crucial role in gene regulation and cellular functions. Through a CRISPR KO screen, we identified miR-940 as a negative regulator of ferroptosis. Overexpression of miR-940 in several cell lines consistently suppressed ferroptosis induced by system xc- inhibition. Notably, multiple cancer patient cohorts with elevated miR-940 levels exhibit reduced survival. Integrated bioinformatic, transcriptomic, and proteomic analyses revealed that miR-940 decreases the expression of ACSL4, LPCAT3, DMT1, and NCOA4, and simultaneously increases levels of GPX4. Pharmacological inhibition of GPX4 attenuated the protective effect of miR-940, indicating that its primary anti-ferroptotic activity is mediated through GPX4. Overall, this gene rewiring is associated with reduced levels of redox-active iron and diminished lipid peroxidation, consistent with ferroptosis suppression. These findings suggest that miR-940 coordinates ferroptosis inhibition, which presents a novel regulatory layer for therapeutic exploration in susceptible cancers.

cell biology↗

bioRxiv2025

TGIF2 is a major regulator of neural stem cell fate and neurogenic priming

During brain development, neural stem cells (NSCs) must balance self-renewal with differentiation and ensure lineage progression. To identify novel regulators of NSCs during neurogenesis, we isolated NSCs by FACS from the mouse cerebral cortex and ganglionic eminence at mid-neurogenesis, and at birth, when gliogenesis starts in both, but neurogenesis only continues in the latter region. RNA-seq and ATAC-seq revealed major transcriptional and chromatin changes between these stages and identified TGFB-Induced Homeobox Factor 2 (TGIF2) as a key candidate factor in neurogenic NSCs. In vitro and in vivo experiments demonstrated a potent role of TGIF2 controlling NSC fate maintenance mediated by its interaction with the SIN3A/HDAC repressor complex suppressing neuronal differentiation genes. Multiomic comparison of NSC and neuron gene expression allowed the comprehensive analysis of neurogenic priming in cortical NSCs, identifying TGIF2 as its major regulator by restraining neuronal differentiation gene activation in NSCs.

neuroscience↗

bioRxiv2024

Sexual dimorphism in molecular profiles of resting human skeletal muscle and the response to acute exercise and endurance training

Biological sex has a strong impact on skeletal muscle metabolism and performance. By a comprehensive investigation of epigenetic, transcriptomic and proteomic differences between female and male skeletal muscle of untrained subjects we provide a molecular basis for the sexual dimorphism of glucose and lipid metabolism. The sex-specific multi-OMICs profiles indicate higher degree of glucose turnover and higher abundance of fast-twitch fibers in males and high degree of lipid handling in females. Eight-week endurance training equalized initial differences toward an endurance-trained proteomic profile in both sexes. The untrained muscle of females was more resistant to an acute exercise challenge since stress-responsive transcripts were predominantly upregulated in males. In myotubes from the same donors, transcriptomic differences were hardly conserved, but could be partially restored by treatment with sex hormones. In conclusion, after only 8 weeks training mitigates deeply rooted sex-specific molecular profiles in skeletal muscle toward a common metabolically beneficial response.

biochemistry↗

bioRxiv2024

The nuclear speckles protein SRRM2 is a new therapeutic target molecule on the surface of cancer cells

The membrane composition of extracellular vesicles (EVs) largely reflects that of the plasma membrane of the cell of origin. We therefore hypothesized that EVs are a source for the detection of hitherto unknown tumor-associated druggable target molecules. For this, we used EVs derived from cancer cell lines for an immunization of a rat. From this immunization, we obtained a monoclonal antibody specific for SRRM2, a protein involved in splicing a major component of nuclear speckles. Here, we used this antibody to demonstrate that SRRM2 is exposed at the surface of most cancer cell lines from various entities and, even more important, on cancer cells in vivo. Moreover, we demonstrate that SRRM2-specific CAR-T cells are killing SRRM2-positive cancer cells electively. Collectively, we identified SRRM2 as a promising new target molecule exposed on the cancer cell surface and show that our SRRM2-specific antibody can be used as a basis for the development of new targeted cancer therapies.

cancer biology↗

bioRxiv2023

Missing view completion for multi-timepoints omics data via representation disentanglement and temporal knowledge transfer

Longitudinal multi-view omics data offer unique insights into the temporal dynamics of individual-level physiology, which provides opportunities to advance personalized healthcare. However, the common occurrence of incomplete views makes extrapolation tasks difficult, and there is a lack of tailored methods for this critical issue. Here, we introduce LEOPARD, an innovative approach specifically designed to complete missing views in multi-timepoint omics data. By disentangling longitudinal omics data into content and temporal representations, LEOPARD transfers the temporal knowledge to the omics-specific content, thereby completing missing views. The effectiveness of LEOPARD is validated on three benchmark datasets constructed with data from the MGH COVID study and the KORA cohort, spanning periods from 3 days to 14 years. Compared to conventional imputation methods, such as missForest, PMM, GLMM, and cGAN, LEOPARD yields the most robust results across the benchmark datasets. LEOPARD-imputed data also achieve the highest agreement with observed data in our analyses for age-associated metabolites detection, estimated glomerular filtration rate-associated proteins identification, and chronic kidney disease prediction. Our work takes the first step toward a generalized treatment of missing views in longitudinal omics data, enabling comprehensive exploration of temporal dynamics and providing valuable insights into personalized healthcare.

bioinformatics↗

bioRxiv2023

The glucocorticoid receptor as a master regulator of Müller cell gliosis in the diabetic retina

Diabetic retinopathy (DR) is considered a primarily microvascular complication of diabetes. Muller glia cells are at the center of the retinal neurovascular unit and play a critical role in DR. We therefore investigated Muller cell-specific signaling pathways that are altered in DR to identify novel targets for gene therapy. Using a multi-omics approach on purified Muller cells from diabetic db/db mice, we found the mRNA and protein expression of the glucocorticoid receptor (GR) to be significantly decreased, while its target gene cluster was down-regulated. Further, oPOSSUM TF analysis and ATAC-sequencing identified the GR as a master regulator of Muller cell gliosis in DR. Cortisol not only increased GR phosphorylation. It also induced changes in the expression of known GR target genes in retinal explants. Finally, retinal functionality was improved by AAV-mediated overexpression of GR in Muller cells. Our study demonstrates an important role of the glial GR in DR and implies that therapeutic approaches targeting this signalling pathway should be aimed at increasing GR expression rather than the addition of more ligand. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=76 SRC="FIGDIR/small/556478v2_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@c7869forg.highwire.dtl.DTLVardef@1574edforg.highwire.dtl.DTLVardef@fb1329org.highwire.dtl.DTLVardef@1a6ee60_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2023

Hmgb2 improves astrocyte to neuron conversion by increasing the chromatin accessibility of genes associated with neuronal maturation in a proneuronal factor-dependent manner

BackgroundDirect conversion of reactive glial cells to neurons is a promising avenue for neuronal replacement therapies after brain injury or neurodegeneration. The overexpression of neurogenic fate determinants in glial cells results in conversion to neurons. For repair purposes, the conversion should ideally be induced in the pathology-induced neuroinflammatory environment. However, very little is known regarding the influence of the injury-induced neuroinflammatory environment and released growth factors on the direct conversion process. ResultsWe established a new in vitro culture system of postnatal astrocytes without epidermal growth factor that reflects the direct conversion rate in the injured, neuroinflammatory environment in vivo. We demonstrated that the growth factor combination corresponding to the injured environment defines the ability of glia to be directly converted to neurons. Using this culture system, we showed that chromatin structural protein high mobility group box 2 (HMGB2) regulates the direct conversion rate downstream of the growth factor combination. We further demonstrated that Hmgb2 cooperates with neurogenic fate determinants, such as Neurog2, in opening chromatin at the loci of genes regulating neuronal maturation and synapse formation. Consequently, early chromatin rearrangements occur during direct fate conversion and are necessary for full fate conversion. ConclusionsOur data demonstrate novel growth factor-controlled regulation of gene expression during direct fate conversion. This regulation is crucial for proper maturation of induced neurons and could be targeted to improve the repair process.

neuroscience↗

bioRxiv2022

Human TRMT2A methylates different components of the translation machinery and contributes to translation fidelity

Methyl-5-uridine (m5U) is one of the most abundant RNA modifications found in cytosolic tRNA. tRNA methyltransferase 2 homolog A (hTRMT2A) is the dedicated mammalian enzyme of m5U formation at tRNA position 54. However, its RNA binding specificity and functional role in the cell are not well understood. Here we dissected structural and sequence requirements for binding and methylation of its RNA targets. Specificity of tRNA modification by TRMT2A is achieved by a combination of modest binding preference and presence of a uridine in position 54 of tRNAs. Mutational analysis together with crosslinking experiments identified a large hTRMT2A-tRNA binding surface. Furthermore, complementing hTRMT2A interactome studies revealed that TRMT2A interacts with proteins involved in RNA biogenesis. Finally, we addressed the question of the importance of TRMT2A function by showing that its knockdown reduces translation fidelity. These findings extend the role of hTRMT2A beyond tRNA modification towards a role in translation.

biochemistry↗

bioRxiv2022

Intestinal myofibroblasts regulate intestinal epithelial cell plasticity via YAP/TAZ

Intestinal stromal cells play a key role as the crypt niche cells during epithelial homeostasis and tumor initiation. However, the underlying cellular and molecular mechanisms remain unclear. We developed various types of three-dimensional (3D) tissue culture models to culture small intestinal myofibroblasts (SI MFs) together with enteroids. SI MFs significantly enhanced self-renewal, lumen formation and survival of enteroids, that was mediated via a paracrine mechanism in a Wnt-independent manner. Such co-cultured enteroids resembled SI organoids derived from Apc+/1638N tumors. Microarray analysis showed upregulation of genes associated with YAP signaling in enteroids co-cultured with SI MFs, which was confirmed by protein quantification by mass spectrometry and could be correlated with findings from human colorectal tumor specimens. Mass spectrometric analysis of conditioned media and inhibitor studies pointed to a role for TGF-{beta} in the SI MF-SI epithelium cross-talk. Altogether, utilizing different 3D stroma-epithelium co-culture models, we demonstrate here that SI MFs have the potential to induce a tumor-like phenotype in the intestinal crypts via a paracrine mechanism, that involves YAP and TGF-{beta}, but not canonical Wnt signaling.

cell biology↗

bioRxiv2022

Release of VAMP5-positive extracellular vesicles from specialized domains of retinal Müller cells in vivo

Cell-cell interactions in the central nervous system are based on the release of molecules mediating signal exchange and providing structural and trophic support through vesicular exocytosis and the formation of extracellular vesicles. The specific mechanisms employed by each cell type in the brain are incompletely understood. Here, we explored the means of communication used by Muller cells, a type of radial glial cells in the retina, which forms part of the central nervous system. Using immunohistochemical, electron microscopic, and molecular analyses, we provide evidence for the release of distinct extracellular vesicles from endfeet and microvilli of retinal Muller cells in adult mice in vivo. We identify VAMP5 as a Muller cell-specific SNARE component that is part of extracellular vesicles and responsive to ischemia, and we reveal differences between the secretomes of immunoaffinity-purified Muller cells and neurons in vitro. Our findings suggest extracellular vesicle-based communication as an important mediator of cellular interactions in the retina.

neuroscience↗

bioRxiv2022

Depletion of the RNA-binding protein PURA triggers changes in posttranscriptional gene regulation and loss of P-bodies

The RNA-binding protein PURA has been implicated in the rare, monogenetic, neurodevelopmental disorder PURA Syndrome. PURA binds both DNA and RNA and has been associated with various cellular functions. Only little is known about its main cellular roles and the molecular pathways affected upon PURA depletion. Here, we show that PURA is predominantly located in the cytoplasm, where it binds to thousands of mRNAs. Many of these transcripts change abundance in response to PURA depletion. The encoded proteins suggest a role for PURA in immune responses, mitochondrial function, autophagy and processing (P)-body activity. Intriguingly, reduced PURA levels decrease the expression of the integral P-body components LSM14A and DDX6 and strongly affect P-body formation in human cells. Furthermore, PURA knockdown results in stabilization of P-body-enriched transcripts, whereas other mRNAs decrease. Hence, reduced PURA levels, as reported in patients with PURA Syndrome, influence the formation and composition of this phase-separated RNA processing machinery. Our study proposes PURA Syndrome as a new model to study the tight connection between P-body-associated RNA regulation and neurodevelopmental disorders. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=150 SRC="FIGDIR/small/479353v2_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@5712f9org.highwire.dtl.DTLVardef@9eb133org.highwire.dtl.DTLVardef@83b7b2org.highwire.dtl.DTLVardef@1912e5c_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2021

Brain injury environment critically influences the connectivity of transplanted neurons

Cell transplantation is a promising approach for the reconstruction of neuronal circuits after brain damage. Transplanted neurons integrate with remarkable specificity into circuitries of the mouse cerebral cortex affected by neuronal ablation. However, it remains unclear how neurons perform in a local environment undergoing reactive gliosis, inflammation, macrophage infiltration and scar formation, as in traumatic brain injury (TBI). To elucidate this, we transplanted cells from the embryonic mouse cerebral cortex into TBI-injured, inflamed-only, or intact cortex of adult mice. Brain-wide quantitative connectomics unraveled graft inputs from correct regions across the brain in all conditions, with pronounced quantitative differences: scarce in intact and inflamed brain, versus exuberant after trauma. In the latter, excessive synapse pruning follows the initial overshoot of connectivity resulting in only a few connections left. Proteomic profiling identifies candidate molecules involved in the synaptic yield, a pivotal parameter to tailor for functional restoration of neuronal circuits. TeaserNeuronal grafts in a brain area affected by trauma receive excessive yet mostly vulnerable inputs from host circuits.

neuroscience↗

bioRxiv2021

Collagen VI regulates motor circuit plasticity and motor performance by cannabinoid modulation

Collagen VI is a key component of muscle basement membranes, and genetic variants can cause monogenic muscular dystrophies. Conversely, human genetic studies recently implicated collagen VI in central nervous system function, with variants causing the movement disorder dystonia. To elucidate the neurophysiological role of collagen VI, we generated mice with a truncation of the dystonia-related collagen 3 (VI) (COL6A3) C-terminal domain (CTD). These Col6a3CTT mice showed a recessive dystonia-like phenotype. We found that COL6A3 interacts with the cannabinoid receptor 1 (CB1R) complex in a CTD-dependent manner. Col6a3CTT mice have impaired homeostasis of excitatory input to the basal pontine nuclei (BPN), a motor control hub with dense COL6A3 expression, consistent with deficient endocannabinoid signaling. Aberrant synaptic input in the BPN was normalized by a CB1R agonist, and motor performance in Col6a3CTT mice was improved by CB1R agonist treatment. Our findings identify a readily therapeutically addressable synaptic mechanism for motor control. SIGNIFICANCE STATEMENTDystonia is a movement disorder characterized by involuntary movements. We previously identified genetic variants affecting a specific domain of the COL6A3 protein as a cause of dystonia. Here, we we created mice lacking the affected domain and observed an analogous movement disorder. Using a protein interaction screen, we found that the affected COL6A3 domain mediates an interaction with the cannabinoid receptor CB1R. Concordantly, our COL6A3-deficient mice showed a deficit in synaptic plasticity linked to a deficit in cannabinoid signaling. Pharmacological cannabinoid augmentation rescued the motor impairment of the mice. Thus, cannabinoid augmentation could be a promising avenue for treating dystonia, and we have identified a possible molecular mechanism mediating this.

neuroscience↗

bioRxiv2021

Proteomic phenotyping of stimulated Mueller cells uncovers profound pro-inflammatory signaling and antigen-presenting capacity

Muller cells are the main macroglial cells of the retina exerting a wealth of functions to maintain retinal homoeostasis. Upon pathological changes in the retina, they become gliotic with both protective and detrimental consequences. Accumulating data also provide evidence for a pivotal role of Muller cells in the pathogenesis of diabetic retinopathy (DR). While microglial cells, the resident immune cells of the retina are considered as main players in inflammatory processes associated with DR, the implication of activated Muller cells in chronic retinal inflammation remains to be elucidated. In order to assess the signaling capacity of Muller cells and their role in retinal inflammation, we performed in-depth proteomic analysis of Muller cell proteomes and secretomes after stimulation with INF{gamma}, TNF, IL-4, IL-6, IL-10, VEGF, TGF{beta}1, TGF{beta}2 and TGF{beta}3. We used both, primary porcine Muller cells and the human Muller cell line MIO-M1 for our hypothesis generating approach. Our results point towards an intense signaling capacity of Muller cells, which reacted in a highly discriminating manner upon treatment with different cytokines. Stimulation of Muller cells resulted in a primarily pro-inflammatory phenotype with secretion of cytokines and components of the complement system. Furthermore, we observed evidence for mitochondrial dysfunction, implying oxidative stress after treatment with the various cytokines. Finally, both MIO-M1 cells and primary porcine Muller cells showed several characteristics of atypical antigen-presenting cells, as they are capable of inducing MHC class I and MHC class II with co-stimulatory molecules. In line with this, they express proteins associated with formation and maturation of phagosomes. Thus, our findings underline the importance of Muller cell signaling in the inflamed retina, indicating an active role in chronic retinal inflammation underlying the pathogenesis of diabetic retinopathy.

immunology↗

bioRxiv2021

Systematic multi-omics cell line profiling uncovers principles of Ewing sarcoma fusion oncogene-mediated gene regulation

Cell lines have been essential for major discoveries in cancer including Ewing sarcoma (EwS). EwS is a highly aggressive pediatric bone or soft-tissue cancer characterized by oncogenic EWSR1-ETS fusion transcription factors converting polymorphic GGAA-microsatellites (mSats) into neo-enhancers. However, further detailed mechanistic evaluation of gene regulation in EwS have been hindered by the limited number of well-characterized cell line models. Here, we present the Ewing Sarcoma Cell Line Atlas (ESCLA) comprising 18 EwS cell lines with inducible EWSR1-ETS knockdown that were profiled by whole-genome-sequencing, DNA methylation arrays, gene expression and splicing arrays, mass spectrometry-based proteomics, and ChIP-seq for EWSR1-ETS and histone marks. Systematic analysis of these multi-dimensional data illuminated hundreds of new potential EWSR1-ETS target genes, the nature of EWSR1-ETS-preferred GGAA-mSats, and potential indirect modes of EWSR1-ETS-mediated gene regulation. Moreover, we identified putative co-regulatory transcription factors and heterogeneously regulated EWSR1-ETS target genes that may have implications for the clinical heterogeneity of EwS. Collectively, our freely available ESCLA constitutes an extremely rich resource for EwS research and highlights the power of leveraging multidimensional and comprehensive datasets to unravel principles of heterogeneous gene regulation by dominant fusion oncogenes.

genomics↗

bioRxiv2021

Tumor-secreted versican co-opts myeloid IKKβ during metastasis

The mechanisms tumor cells use to hijack the immune system are largely uncharted. Here we used bioluminescent nuclear factor (NF)-{kappa}B reporter mice and macrophages to discover that metastatic tumors trigger NF-{kappa}B activation in host macrophages, dependent on mutant KRAS signaling and delivered via secretory versican. Versican activates NF-{kappa}B in tumor-associated macrophages via inhibitor of NF-{kappa}B kinase (IKK) {beta}, resulting in release of interleukin (IL)-1{beta} into the tumor microenvironment. Versican silencing in cancer cells or conditional IKK{beta} deletion in macrophages prevents myeloid NF-{kappa}B activation and metastasis. Versican is overexpressed and/or mutated in human cancers and metastatic effusions with KRAS mutations, predicts poor survival, can aid in the development of diagnostic platforms for pleural metastasis, and is druggable via toll-like receptor (TLR) 1/2 inhibition. The data indicate a cardinal role for tumor-derived versican in establishing cross-talk with macrophage IKK{beta} during metastasis and may foster the development of new therapies and diagnostic tools.

cancer biology↗

bioRxiv2021

Proteomic signature of the Dravet syndrome in the genetic Scn1a-A1783V mouse model

BackgroundDravet syndrome is a rare, severe pediatric epileptic encephalopathy associated with intellectual and motor disabilities. Proteomic profiling in a mouse model of Dravet syndrome can provide information about the molecular consequences of the genetic deficiency and about pathophysiological mechanisms developing during the disease course. MethodsA knock-in mouse model of Dravet syndrome with Scn1a haploinsufficiency was used for whole proteome, seizure and behavioral analysis. Hippocampal tissue was dissected from two-(prior to epilepsy manifestation) and four-(following epilepsy manifestation) week-old male mice and analyzed using LC-MS/MS with label-free quantification. Proteomic data sets were subjected to bioinformatic analysis including pathway enrichment analysis. The differential expression of selected proteins was confirmed by immunohistochemical staining. ResultsThe findings confirmed an increased susceptibility to hyperthermia-associated seizures, the development of spontaneous seizures, and behavioral alterations in the novel Scn1a-A1873V mouse model of Dravet syndrome. As expected, proteomic analysis demonstrated more pronounced alterations following epilepsy manifestation. In particular, proteins involved in neurotransmitter dynamics, receptor and ion channel function, synaptic plasticity, astrogliosis, neoangiogenesis, and nitric oxide signaling showed a pronounced regulation in Dravet mice. Pathway enrichment analysis identified several significantly regulated pathways at the later time point, with pathways linked to synaptic transmission and glutamatergic signaling dominating the list. ConclusionIn conclusion, the whole proteome analysis in a mouse model of Dravet syndrome demonstrated complex molecular alterations in the hippocampus. Some of these alterations may have an impact on excitability or may serve a compensatory function, which, however, needs to be further confirmed by future investigations. The proteomic data indicate that, due to the molecular consequences of the genetic deficiency, the pathophysiological mechanisms may become more complex during the course of the disease. Resultantly, the management of Dravet syndrome may need to consider further molecular and cellular alterations. Ensuing functional follow-up studies, this data set may provide valuable guidance for the future development of novel therapeutic approaches.

neuroscience↗