Biology subjects

Hausch, F.

Publications and source records attributed to Hausch, F..

12 recordsLinked to original sources

bioRxiv2025

Pharmacological Inhibition of FKBP51 Mitigates Early Life Adversity-Induced Social Deficits

Early life adversity (ELA) is a major risk factor for psychiatric disorders, but targeted preventative strategies are lacking due to poor mechanistic insight. The FKBP51 protein, a co-chaperone of the glucocorticoid receptor, is a key mediator of stress vulnerability. We tested if pharmacological inhibition of FKBP51 with the selective inhibitor SAFit2 prevents the long-term consequences of ELA. Mice exposed to ELA exhibited persistent deficits in social behavior, manifesting as social subordination in adolescence and adulthood. Early-life SAFit2 treatment fully rescued these ELA-induced behavioral impairments. Transcriptional profiling across six stress-relevant brain regions revealed that SAFit2 normalized ELA-driven gene expression changes, particularly in the medial prefrontal cortex and nucleus accumbens. Functional analysis showed the rescue converged on immunoregulatory and neuroactive ligand-receptor signaling pathways. Our findings establish FKBP51 as a critical pharmacological target for reversing the lasting impact of early life adversity on brain function, offering a path toward preventative treatment for ELA-related psychopathology.

neuroscience↗

bioRxiv2025

A new FKBP51-GR-p23-Hsp902 multi-cochaperone complex identified and characterized by site-specific in-cell photocrosslinking

Glucocorticoid receptor (GR) activity and maturation are closely regulated by Hsp90 co-chaperones such as FKBP51, FKBP52 and p23. These co-chaperones bind to and regulate the GR, but their mutual interplay, the details of the interactions between them and their temporal dynamics are still unclear. Here we utilized UV-inducible crosslinking in living cells to map the interaction site of p23 and the GR, as well as p23 and FKBP51 at a single residue resolution. Surprisingly, we detected a novel multi-co-chaperone complex consisting of the GR, p23, FKBP51 and Hsp90, where both FKBP51 and p23 bind to the GR simultaneously. In this complex, FKBP51, but not the close homolog FKBP52, stabilizes the GR-p23 interaction. This is mediated in part by direct contacts between the FK1 domain of FKBP51 and the C-terminus of p23. Our findings refine the state of GR prior to activation, add a new layer of GR regulation by chaperones, provide evidence for the functional differences between FKBP51 and FKBP52, and underscore the power of photocrosslinking to functionally probe protein-protein contacts inside living cells. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=133 SRC="FIGDIR/small/658717v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@1431173org.highwire.dtl.DTLVardef@2ebfb9org.highwire.dtl.DTLVardef@12d37e9org.highwire.dtl.DTLVardef@1b1d5e3_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2025

Heterobifunctional Protein Binders Enable Cell Type-Specific Killing Through In-cell Enrichment

Non-catalytic heterobifunctional molecules promise to expand the range of therapeutic options by establishing complexes between key target proteins and accessory presenter proteins equipped with additional properties. Here, we systematically investigate the rational design of such molecules, explore the biochemical basis of complex formation and determine how they achieve cellular efficacy using the endogenously expressed immunophilin FKBP12 and the transcriptional regulator BRD4 as paradigms. We present classes of bifunctional molecules that enable selective, FKBP12-dependent killing of specific cell types at subnanomolar concentrations and allow to differentiate between closely similar bromodomains. We propose that the strongly potentiated efficacy of these bifunctional compounds is based on cellular enrichment through binding to the highly abundant presenter protein FKBP12, a mechanism we term "CellTrap". Our findings substantiate the concept that highly expressed, non-essential proteins can be repurposed as selective recruiters to expand therapeutic windows of existing small-molecule inhibitors, opening new avenues for designing targeted drugs with improved cell-type specificity.

biochemistry↗

bioRxiv2025

Identification and characterization of potent and selective inhibitors for the B0AT2/SLC6A15 amino acid transporter

1.The gene SLC6A15 encodes the protein B0AT2, a transporter for neutral amino acids. It is highly expressed in the brain and has been associated with depression but little is otherwise know about its function. In this study, we identified the first inhibitors of this protein to pharmacologically investigate its function. The transporter activity was evaluated using a cellular uptake of the substrate 3H-proline. A miniaturized assay was developed and used for a High Throughput Screening (HTS) of 200,000 compounds. Hits were tested for cell toxicity and selectivity versus related transporters of the SLC6 family. The most promising inhibitors were validated by proline uptake and neurite outgrowth in primary hippocampal neurons. Of the 10 chemical scaffolds identified, a 1,5-benzodiazepine series had the most promising selectivity and structure-activity relationship (SAR) profile. The best compounds showed drug-like properties and inhibited B0AT2 with an IC50 of 250 nM both in SLC6A15-overexpressing HEK293 cells and primary neurons, with no detectable inhibition (> 80{micro}M) of SERT, DAT, GAT1, or NTT4/SLC6A17. These compounds also dose-dependently stimulated neurite outgrowth in primary neurons. The identified compounds are the first inhibitors of the amino acids transporter B0AT2/SLC6A15. Their potency, selectivity and physicochemical properties allow to target the transporter in relevant biological systems and to initiate new studies to understand its role and implication in diseases.

biochemistry↗

bioRxiv2025

Stress, Epigenetic Remodeling and FKBP51: Pathways to Chronic Pain Vulnerability

Stress is thought to contribute to the persistence of pain and comorbid anxiety, yet the underlying mechanisms remain unclear. In our pre-clinical model, sub-chronic stress exacerbated subsequently induced inflammatory pain and accelerated the development of comorbid anxiety. DNA methylation analysis of spinal cord tissue after stress exposure revealed hypomethylation in the Fkbp5 promoter site for the canonical FKBP51 transcript and other stress-related genes. However, most epigenetic changes in key regulatory regions did not correlate with changes in gene expression assessed by RNA sequencing, suggesting that stress exposure had remodeled the epigenome without altering gene activity and primed genes for hyper-responsiveness to future challenges. FKBP51 inhibition during stress exposure reduced the exacerbation of inflammatory pain by stress and reversed several stress-induced DNA methylation changes in promoter regions of genes associated with stress and nociception, including Rtn4, Cdk5 and Nrxn1, but not Fkbp5. These results indicate that sub-chronic stress leads to the hypomethylation of Fkbp5 and increased susceptibility to chronic pain driven by FKBP51, but reversing Fkbp5 hypomethylation is not necessary to prevent chronic pain vulnerability, which is likely driven by complex epigenetic regulation of multiple stress-regulated genes.

neuroscience↗

bioRxiv2024

Acute and early stress axis modulation in joint disease permanently reduces pain and emotional comorbidities

Chronic pain affects 20-30% of the population and imposes a significant socio-economic burden as it is often accompanied by substantial emotional comorbidities such as anxiety and depression. Yet, the mechanisms underlying the interactions between the sensory and emotional aspects of chronic pain remain poorly understood. Here, we investigated the role of FKBP51, a regulator of the stress response, in mediating both sensory and emotional symptoms of chronic pain. Inhibition of FKBP51, via genetic deletion or pharmacological blockade, in persistent joint pain reduced fast-onset sensory, functional and activity-related symptoms, as well as late anxio-depressive comorbidities. FKBP51 inhibition after the establishment of the hypersensitive state provided only temporary symptoms relief, while acute inhibition at disease onset protected from the full development of sensory and anxio-depressive symptoms for up to 6 months. Our results also indicated that early pain symptoms could predict the late sensory and emotional outcomes of chronic pain. RNA sequencing of spinal cord tissue revealed that late FKBP51 inhibition transiently altered nociceptive genes associated with mechanical hypersensitivity. In contrast, early inhibition persistently downregulated the Naaa gene, a key regulator of the transition to chronic pain, and reorganized spinal cilia. Our results indicate that early FKBP51 inhibition after injury can persistently reduce chronic pain and prevent the onset of associated emotional comorbidities by modulating critical spinal neurobiological pathways that play pivotal roles in the transition to chronic pain. Significance statementOur study reveals that early inhibition of FKBP51, a modulator in the stress axis, at the onset of joint damage provides sustained pain relief and significantly delays or prevents emotional comorbidities in a sex-dependent manner. In contrast, FKBP51 inhibition initiated after chronic pain is established results in only temporary symptoms improvement. These findings highlight a critical therapeutic window during which timely intervention can prevent the transition from acute to chronic pain. By establishing a predictive link between early therapeutic response and long-term outcomes, this work has important clinical implications for proactive and personalized chronic pain management.

neuroscience↗

bioRxiv2023

GlnA3Mt is able to glutamylate spermine but it is not essential for the detoxification of spermine in Mycobacterium tuberculosis

Mycobacterium tuberculosis is well adapted to survive and persist in the infected host, escaping the host immune response. Since polyamines, which are synthesized by infected macrophages are able to inhibit the growth of M. tuberculosis, the pathogen needs strategies to cope with toxic spermine. The actinomycete Streptomyces coelicolor, closely related to M. tuberculosis makes use of a gamma-glutamylation pathway to functionally neutralize spermine. We therefore considered whether a similar pathway would be functional in M. tuberculosis. In the current study we demonstrated that M. tuberculosis growth was inhibited by the polyamine spermine. Using a glutamine synthetase-based in vitro enzymatic activity assay we determined that GlnA3Mt (Rv1878) is a gamma-glutamylspermine synthetase. In an in vitro phosphate release assay we showed that purified His-Strep-GlnA3Mt as well as native GlnA3Mt prefer spermine as a substrate to putrescine, cadaverine, spermidine or other monoamines and amino acids, suggesting that GlnA3Mt may play a specific role in the detoxification of the polyamine spermine. However, the deletion of the glnA3 gene in M. tuberculosis did not result in growth inhibition or enhanced sensitivity of M. tuberculosis in the presence of high spermine concentrations. Subsequent RNAsequencing of M. tuberculosis bacteria revealed that the gene cluster consisting of the efflux pump-encoding rv3065-rv3066-rv3067 genes is upregulated upon spermine treatment, suggesting its involvement in bacterial survival under elevated spermine concentrations. IMPORTANCEAntibiotics for the treatment of Mycobacterium tuberculosis infections attack classical bacterial targets, such as the cell envelope or the ribosome. Upon M. tuberculosis infection macrophages synthesize the polyamine spermine which - at elevated concentrations - is toxic for M. tuberculosis. Based on our investigations of spermine resistance in the closely related actinomycete Streptomyces coelicolor, we hypothesized that the glutamyl-sperminesynthetase GlnA3 may be responsible for resistance against toxic spermine. Here we show that the mycobacterial glutamyl-sperminesynthetase indeed can inactivate spermine by glutamylation. However, GlnA3 is probably not the only resistance mechanism since a glnA3 mutant of M. tuberculosis can survive under spermine stress. Gene expression studies suggest that an efflux pump may participate in resistance. The functional role of GlnA3Mt as well as of the spermine transporter in the pathogenicity of M. tuberculosis is of special interest for their validation as new targets of novel anti-tubercular drugs.

microbiology↗

bioRxiv2023

Involvement of FKBP5, but not of stress, in alcohol memory reconsolidation

Relapse is a fundamental challenge in drug addiction, often evoked by exposure to drug-associated cues. Upon retrieval, memories become temporarily labile before re-stabilizing in a process termed reconsolidation. Therefore, targeting the reconsolidation process offers a therapeutic approach for relapse prevention via the disruption of the drug-cue memories. We recently demonstrated that retrieval of contextual alcohol memories increased the expression of the mRNA encoding for FK506 binding protein 51 (FKBP51), a regulator of the hypothalamic-pituitary-adrenal (HPA) axis. Here, we explored the role of the HPA axis, and FKBP5/FKBP51 in particular, in the reconsolidation of alcohol memories. We found that the FKBP51 inhibitor SAFit2 given before alcohol-memory retrieval using contextual cues prevented the extinction of alcohol place preference behavior in female mice, suggesting that this protein may play a role in cognitive flexibility in a sex-dependent manner. Conversely, the retrieval of alcohol memories using an odor-taste cue did not affect Fkbp5 expression in rats with a history of chronic alcohol consumption, suggesting that FKBP5 may play a differential role in different alcohol-associated memories. In addition, we provide evidence for HPA axis activation following alcohol memory retrieval, by showing that exposure to an alcohol-associated context led to elevated corticosterone secretion. However, we found that the reconsolidation process was unaffected by HPA axis-related manipulations, namely stress exposure, and administration of corticosterone or the glucocorticoid receptors inhibitor, mifepristone. Our results suggest that although FKBP5 can affect cognitive flexibility, and thereby impact the reconsolidation of alcohol memories, this effect is not likely mediated by HPA axis-related mechanisms.

neuroscience↗

bioRxiv2023

Legionella pneumophila macrophage infectivity potentiator protein appendage domains modulate protein dynamics and inhibitor binding

Macrophage infectivity potentiator (MIP) proteins are widespread in human pathogens including Legionella pneumophila, the causative agent of Legionnaires disease and protozoans such as Trypanosoma cruzi. All MIP proteins contain a FKBP (FK506 binding protein)-like prolyl-cis/trans- isomerase domain that hence presents an attractive drug target. Some MIPs such as the Legionella pneumophila protein (LpMIP) have additional appendage domains of mostly unknown function. In full- length, homodimeric LpMIP, the N-terminal dimerization domain is linked to the FKBP-like domain via a long, free-standing stalk helix. Combining X-ray crystallography, NMR and EPR spectroscopy and SAXS, we elucidated the importance of the stalk helix for protein dynamics and inhibitor binding to the FKBP-like domain and bidirectional crosstalk between the different protein regions. The first comparison of a microbial MIP and a human FKBP in complex with the same synthetic inhibitor was made possible by high-resolution structures of LpMIP with a [4.3.1]-aza-bicyclic sulfonamide and provides a basis for designing pathogen-selective inhibitors. Through stereospecific methylation, the affinity of inhibitors to L. pneumophila and T. cruzi MIP was greatly improved. The resulting X-ray inhibitor-complex structures of LpMIP and TcMIP at 1.49 and 1.34 [A], respectively, provide a starting point for developing potent inhibitors against MIPs from multiple pathogenic microorganisms.

biophysics↗

bioRxiv2023

Large-scale in-cell photocrosslinking at single residue resolution reveals the molecular basis for glucocorticoid receptor regulation by immunophilins

The large immunophilins FKBP51 and FKBP52 play key roles in the Hsp90-mediated maturation of steroid hormone receptors, which is crucial for stress-related disorders and correct sexual embryonic development, respectively 1-3. A prominent regulatory target is the glucocorticoid receptor (GR), whose activation is repressed by FKBP51 4,5 and facilitated by FKBP52 6,7. Despite their vital roles, the molecular modes of action of FKBP51 and FKBP52 are poorly understood since the transient key states of FKBP-mediated GR-regulation have remained experimentally elusive. Here we present the architecture and functional annotation of FKBP51-, FKBP52- and p23-containing Hsp90-apoGR preactivation complexes, trapped by systematic incorporation of photoreactive amino acids 8,9 inside human cells. The identified crosslinking sites depended on a functional Hsp90 chaperone cycle, were disrupted by GR activation, and clustered in characteristic patterns, defining the relative orientation and contact surfaces within the FKBP/p23-apoGR complexes. Strikingly, GR binding to the FKBPFK1 but not the FKBPFK2 domains were modulated by FKBP ligands, explaining the lack of FKBP51-mediated GR derepression by certain classes of FKBP ligands. These findings show how FKBP51 and FKBP52 differentially interact with the apoGR ligand binding domain, they explain the differentiated pharmacology of FKBP51 ligands, and provide a structural basis for the development of FKBP ligands with higher efficacy.

biochemistry↗

bioRxiv2020

Stress-primed secretory autophagy drives extracellular BDNF maturation

The stress response is an essential mechanism that strives to maintain homeostasis, and its disruption is implicated in several psychiatric disorders. As a cellular response to stressors, autophagy is activated to regulate homeostasis through protein degradation and recycling. Secretory autophagy is a recently described pathway where autophagosomes fuse with the plasma membrane rather than lysosomes. In this study, we demonstrate that glucocorticoid-mediated stress enhances secretory autophagy, via the stress-responsive co-chaperone FK506-binding protein 51. We identified the matrix metalloproteinase 9 (MMP9) as one of the stress-induced secreted proteins. Using cellular assays and in vivo microdialysis, we further found that stress-enhanced MMP9 secretion increases the cleavage of pro-brain derived neurotrophic factor (proBDNF) to its mature form. BDNF is essential for adult synaptic plasticity and its pathway is associated with major depression and posttraumatic stress disorder. These findings unravel a novel mechanistic link between stress, stress adaptation and the development of psychiatric disorders, with possible therapeutic implications.

molecular biology↗

bioRxiv2018

Epigenetic derepression of FKBP5 by aging and stress contributes to NF-kB-driven inflammation and cardiovascular risk

Aging and psychosocial stress are associated with increased inflammation and disease risk, but the underlying molecular mechanisms are poorly understood. Because both aging and stress are also associated with lasting epigenetic changes, a plausible hypothesis is that stress exposure along the lifespan could confer disease risk by epigenetically deregulating molecules involved in inflammatory processes. Here, by combining large-scale analyses in human cohorts with mechanistic in vitro investigations, we found that FKBP5, a protein implicated in stress physiology, contributes to these relations. Across independent human cohorts (total n=3,131), aging and stress-related phenotypes were synergistically associated with epigenetic derepression of FKBP5. These age/stress-related epigenetic effects were recapitulated in an in vitro model of replicative senescence, whereby we exposed replicating human fibroblasts to stress (glucocorticoid) hormones. Unbiased genome-wide analyses in human blood linked higher FKBP5 mRNA with a proinflammatory profile and altered NF-{kappa}B-related gene networks. Accordingly, experiments in immune cells showed that FKBP5 overexpression promotes inflammation by strengthening the interactions of NF-{kappa}B regulatory kinases, whereas opposing FKBP5 either by genetic deletion (CRISPR/Cas9-mediated) or selective pharmacological inhibition prevented the effects on NF-{kappa}B. Further, the age/stress-related epigenetic signature enhanced FKBP5 responsivity to NF-{kappa}B through a positive feedback loop and was present in individuals with a history of acute myocardial infarction, a disease state linked to peripheral inflammation. These findings suggest that FKBP5-NF-{kappa}B signaling mediates inflammation associated with aging and stress, potentially contributing to cardiovascular risk, and may thus point to novel biomarker and treatment possibilities.\n\nSignificanceDiseases of the aging are the leading cause of morbidity and mortality. Elucidating the molecular mechanisms through which modifiable factors, such as psychosocial stress, confer risk for aging-related disease can have profound implications. Here, by combining studies in humans with experiments in cells, we find that aging and stress synergize to epigenetically derepress FKBP5, a protein implicated in stress physiology. Higher FKBP5 promotes inflammation by activating the master immune regulator NF-{kappa}B, whereas opposing FKBP5 - either genetically or pharmacologically- prevents the effects on NF-{kappa}B. Further, the age/stress-related epigenetic signature of FKBP5 is associated with history of myocardial infarction, a disease state linked to inflammation. These findings provide molecular insights into stress-related disease and may point to novel biomarker and treatment possibilities.

genomics↗