Biology subjects

Klengel, C.

Publications and source records attributed to Klengel, C..

8 recordsLinked to original sources

bioRxiv2026

Stressor Identity Shapes Reactivity To Subsequent Stress

Extensive work has established that exposure to a single acute stressor can have profound impacts on future reactivity to new stressors, including enhanced acquisition of new fear. The impact of stressor type on development of stress sensitization, however, remains unclear. We investigated whether fundamentally different acute stressors (shock, social defeat, or restraint stress) differ in ability to sensitize acquisition of a new, contextually distinct fear memory in adult male mice two weeks following stress exposure. Stressor subtype differentially sensitized new fear learning; specifically, shock and social defeat - but not restraint stress - led to enhanced recall of a new shock-paired fear memory. We also compared how stressor subtypes differentially engage the brain-periphery interactions that regulate stress responsivity. Notably, restraint stress, which did not lead to fear sensitization to foot shock, drove similar or even greater corticosterone release than other stressors, suggesting that the neuroendocrine response to the original stressor is dissociable from development of a behavioural fear sensitization response. Using the immediate-early gene FOS as a marker of neural activity, all conditions - including the context-only control condition - activated a similar number of neurons in the basolateral amygdala. In contrast, only stressful conditions activated the paraventricular nucleus of the hypothalamus, and restraint stress selectively spared activation of the dorsal hippocampus. These data collectively suggest that future responses to stress depend critically on the identity of previously experienced stressors, rather than simply on prior exposure to stress, establishing a powerful comparative model for investigating the specific mechanisms underlying stress-enhanced fear learning.

neuroscience↗

bioRxiv2026

Fine mapping of PTSD GWAS reveals a role for amygdala Foxp2 in regulation of fear and threat responses

Post-traumatic Stress Disorder (PTSD) is a debilitating psychiatric condition caused by severe trauma exposure and characterized by ongoing dysregulation of fear processing, hyperarousal, and amygdala activation, but with limited effective treatments. Recent large-scale genome-wide association studies (GWAS) of PTSD have identified the transcription factor FOXP2 as a highly-significant, top putative risk gene. Both fine-mapping of the PTSD GWAS with amygdala-specific expression quantitative trait loci (eQTL) data, and transcriptome-wide association analyses, show that altered expression of FOXP2 is associated with increased PTSD risk. In vertebrates, FOXP2 mRNA is most densely expressed in the intercalated cells (ITCs) of the amygdala. ITC neurons receive excitatory input from external regulatory and sensory brain regions, as well as the basolateral amygdala, and send inhibitory projections to the central amygdala, which regulates downstream fear responses. While ITCs are critical for conditioned fear acquisition and extinction, the role of the FOXP2 gene in modulating fear-related behaviors remains unknown. Here, we used complementary bioinformatic, molecular, circuit, behavioral, and electrophysiological approaches to characterize the function of mouse (Foxp2) and human (FOXP2) orthologs in amygdala-mediated fear learning. To assess Foxp2 function in vivo, we first used shRNA-mediated knockdown (KD) of Foxp2 in ITC neurons of adult mice. Targeted Foxp2 KD robustly and significantly reduced freezing (threat/fear expression) during and after auditory fear conditioning. Whole-cell recordings from individual ITC neurons revealed that Foxp2 KD increased their intrinsic membrane excitability and action potential frequency, consistent with hypothesized enhanced inhibitory output to the central amygdala and thus reduced fear expression. This hyperexcitability was associated with reduced potassium channel conductance. Bulk RNA sequencing (RNA-seq) of mouse amygdala after ITC Foxp2 KD confirmed decreased potassium channel transcription and revealed broader Foxp2-dependent regulation of multiple genes implicated in fear learning, including Wnt, Crh (which encodes corticotropin-releasing hormone), and neurokinin signaling pathways. Consistent with these findings, bulk RNA-seq of medial amygdala postmortem tissue from humans with PTSD versus neurotypical controls showed decreased potassium channel transcription in samples with low FOXP2 expression. Downstream transcriptional changes following Foxp2 KD in the mouse amygdala also showed marked enrichment of genes identified in PTSD risk loci from the largest PTSD GWAS to date. Specifically, downregulated genes were enriched for mouse orthologs of Tier 1 PTSD GWAS risk genes. This enrichment appears to reflect subcortical Foxp2 signaling within the amygdala, driven predominantly by decreased expression of genes lacking promoter-anchored chromatin loops. This finding suggests that Foxp2 may directly bind regulatory elements of multiple top PTSD risk genes, acting as a key regulatory node for fear-related pathways in the amygdala. Collectively, our findings establish FOXP2 as a central transcriptional regulator of fear-related gene networks in the amygdala and potential regulatory hub for PTSD genetic risk.

neuroscience↗

bioRxiv2024

Spermidine alleviates depression via control of the stress response

Depression is a stress-associated disorder, and it represents a major global health issue. Its pathophysiology is complex and remains insufficiently understood, with current medications often showing limited efficacy and undesirable side effects. Here, we identify imbalanced polyamine levels and dysregulated autophagy as key components of the acute stress response in humans, and as hallmarks of chronic stress and depressive disorders. Moreover, conventional antidepressant pharmacotherapy increases endogenous plasma concentrations of the polyamine spermidine exclusively in patients who respond to the treatment, suggesting a link between spermidine and successful outcomes. In a clinical trial, involving drug-naive depressed individuals, three weeks of spermidine supplementation increased autophagy and alleviated symptoms of depression. Behavioral and mechanistic findings of spermidine supplementation were validated in various mouse stress and depression models. In summary, spermidine supplementation mitigates polyamine dysregulation and stimulates autophagy under pathological stress conditions, offering a novel and well-tolerated treatment approach for stress-related depressive disorders.

neuroscience↗

bioRxiv2024

A novel epigenetic clock for rhesus macaques unveils an association between early life adversity and epigenetic age acceleration

Because DNA methylation changes reliably with age, machine learning models called epigenetic clocks can estimate an individuals age based on their DNA methylation profile. This epigenetic measure of age can deviate from ones true age, and the difference between the epigenetic age and true age, known as epigenetic age acceleration (EAA), has been found to directly correlate with morbidity and mortality in adults. Emerging evidence suggests that EAA is also associated with aberrant health outcomes in children, making epigenetic clocks useful tools for studying aging and development. We developed two highly accurate epigenetic clocks for the rhesus macaque, utilizing 1,008 blood samples from 690 macaques between 2 days and 23.4 years of age with diverse genetic backgrounds and exposure to environmental conditions. The first clock, which is trained on all samples, achieves a Pearson correlation between true age and predicted age of 0.983 and median absolute error of 0.210 years. To study phenotypes during development, the second clock is optimized for macaques younger than 6 years and achieves a Pearson correlation of 0.974 and a median absolute error of 0.148 years. Using the latter clock, we investigated whether epigenetic aging is affected by early life adversity in the form of infant maltreatment. Our data suggests that maltreatment and increased hair cortisol levels are associated with epigenetic age acceleration right after the period of maltreatment.

neuroscience↗

bioRxiv2023

SKA2 regulated hyperactive secretory autophagy drives neuroinflammation-induced neurodegeneration

High levels of proinflammatory cytokines induce neurotoxicity and catalyze inflammation-driven neurodegeneration, but the specific release mechanisms from microglia remain elusive. We demonstrate that secretory autophagy (SA), a non-lytic modality of autophagy for secretion of vesicular cargo, regulates neuroinflammation-mediated neurodegeneration via SKA2 and FKBP5 signaling. SKA2 inhibits SA-dependent IL-1{beta} release by counteracting FKBP5 function. Hippocampal Ska2 knockdown in mice hyperactivates SA resulting in neuroinflammation, subsequent neurodegeneration and complete hippocampal atrophy within six weeks. The hyperactivation of SA increases IL-1{beta} release, initiating an inflammatory feed-forward vicious cycle including NLRP3-inflammasome activation and Gasdermin D (GSDMD)-mediated neurotoxicity, which ultimately drives neurodegeneration. Results from protein expression and co-immunoprecipitation analyses of postmortem brains demonstrate that SA is hyperactivated in Alzheimers disease. Overall, our findings suggest that SKA2-regulated, hyperactive SA facilitates neuroinflammation and is linked to Alzheimers disease, providing new mechanistic insight into the biology of neuroinflammation.

neuroscience↗

bioRxiv2021

Cell-type specific induction of cyclo-oxygenase-2 in layer II/III prefrontal cortical neurons mediates stress-induced anxiety phenotypes in mice.

The ability of the medial prefrontal cortex (mPFC) to exert top-down control of behavior is affected by stress. The molecular response of mPFC to stress is incompletely understood, however, in part because of the regions cellular heterogeneity. Here we used single nucleus RNA sequencing (snRNAseq) to map specific molecular cell types within the mPFC and to detect cell-type specific transcriptional changes to foot-shock stress. We identified Ptgs2, encoding cyclo-oxygenase 2, as an important candidate that is upregulated in layer II/III excitatory neurons after stress. Specifically, Ptgs2 was transiently upregulated with shock-induced fear learning and fear expression, along with Bdnf, Nptx2, and Lingo1, in a layer II/III neuronal population marked by the neuronal excitatory gene Slc17a7 and cell-type specific neuropeptide Penk. These dynamic cell-type specific expression patterns identified with snRNAseq were validated with quantitative fluorescent in situ hybridization. Using a pharmacological approach, we found that systemic lumiracoxib, a selective Ptgs2-inhibitor, led to a significant reduction in fear expression. Furthermore, genetic ablation of Ptgs2 in excitatory Camk2a-expressing neurons led to reduced stress-induced anxiety-like behaviors. Together these findings suggest that Ptgs2 is expressed in a dynamic, cell-type specific way in Layer II/III Penk+ neurons in mPFC, and that its role in prostaglandin and /or endocannabinoid regulation within these neurons may be an important mediator of stress-related behavior.

neuroscience↗

bioRxiv2021

Genome-wide transcriptional profiling uncovers a similar oligodendrocyte-related transcriptional response to acute and chronic alcohol drinking in the amygdala

Alcohol intake progressively increases after prolonged consumption of alcohol, but relatively few new therapeutics targeting development of alcohol use disorder (AUD) have been validated. Here, we conducted a genome-wide RNA-sequencing (RNA-seq) analysis in mice exposed to different modes (acute vs chronic) of ethanol drinking. We focused on transcriptional profiles in the amygdala including the central and basolateral subnuclei, a brain area previously implicated in alcohol drinking and seeking, demonstrating distinct gene expression patterns and canonical pathways induced by both acute and chronic intake. Surprisingly, both drinking modes triggered similar transcriptional changes, including up-regulation of ribosome-related/translational pathways and myelination pathways, and down-regulation of chromatin binding and histone modification. Notably, multiple genes that were significantly regulated in mouse amygdala with alcohol drinking, including Atp2b1, Slc4a7, Nfkb1, Nts, and Hdac2, among others had previously been associated with human AUD via GWAS or other genomic studies. In addition, analyses of hub genes and upstream regulatory pathways predicted that voluntary ethanol consumption affects epigenetic changes via histone deacetylation pathways, oligodendrocyte and myelin function, and oligodendrocyte-related transcriptional factor, Sox17. Overall, our results suggest that the transcriptional landscape in the central and basolateral subnuclei of the amygdala is sensitive to voluntary alcohol drinking. They provide a unique resource of gene expression data for future translational studies examining transcriptional mechanisms underlying the development of AUD due to alcohol consumption.

neuroscience↗

bioRxiv2019

Analysis of Genetically Regulated Gene Expression identifies a trauma type specific PTSD gene, SNRNP35

PTSD has significant genetic heritability; however, it is unclear how genetic risk influences tissue-specific gene expression. We used brain and non-brain transcriptomic imputation models to impute genetically regulated gene expression (GReX) in 9,087 PTSD-cases and 23,811 controls and identified thirteen significant GReX-PTSD associations. The results suggest substantial genetic heterogeneity between civilian and military PTSD cohorts. The top study-wide significant PTSD-association was with predicted downregulation of the Small Nuclear Ribonucleoprotein U11/U12 Subunit 35 (SNRNP35) in the BA9 region of the prefrontal cortex (PFC) in military cohorts. In peripheral leukocytes from 175 U.S. Marines, the observed PTSD differential gene expression correlated with the predicted blood GReX differences for these individuals, and deployment stress downregulated SNRNP35 expression, primarily in Marines with post-deployment PTSD. SNRNP35 is a subunit of the minor spliceosome complex and SNRNP35 knockdown in cells validated its functional importance in U12-intron splicing. Finally, mimicking acute activation of the endogenous stress axis in mice downregulated PFC Snrnp35 expression.

genetics↗