Biology subjects

Schackmuth, M. K.

Publications and source records attributed to Schackmuth, M. K..

5 recordsLinked to original sources

bioRxiv2025

Enabling wider access to human molecular neuroscience research in pain: A simple preservation method for human dorsal root ganglion neurons in Hibernate A media

The use of human dorsal root ganglion (DRG) from organ donors opens the door for research into the molecular biology and physiology of human nociceptors; however, there are barriers to working with this tissue including logistical difficulties and limited access. We present an approach using Hibernate media to temporarily store either whole DRGs or dissociated DRG neurons prior to culturing and functional testing. Dissociation of DRGs following temporary storage (4-16hrs) in Hibernate media resulted in similar neuronal and immune cell yield as acutely dissociated DRGs. Neurons derived from DRGs stored in Hibernate media prior to dissociation exhibited similar electrophysiological properties and capsaicin responses as acutely dissociated DRG neurons. Similarly, neurons from acutely dissociated DRGs stored in Hibernate media (>24hrs) and shipped to geographically distant laboratories produced neuronal cultures displaying comparable electrophysiological properties as acutely cultured neurons. This approach overcomes insurmountable logistical burdens and increases access to freshly recovered human DRGs.

neuroscience↗

bioRxiv2025

AAV-mediated gene therapy for SLC13A5 citrate transporter disorder rescues epileptic and metabolic phenotypes

SLC13A5 citrate transporter disorder is a rare epileptic encephalopathy caused by loss of function pathogenic variants in the SLC13A5 gene. Loss of sodium/citrate cotransporter (NaCT) function causes a severe early life epilepsy resulting in life-long developmental disabilities and increased extracellular citrate. Current antiseizure medications may reduce seizure frequency, yet more targeted treatments are needed to address the epileptic and neurodevelopmental SLC13A5 phenotype. We performed preclinical studies in SLC13A5 deficient mice evaluating phenotype rescue with adeno-associated virus (AAV) vector carrying a functional copy of the human SLC13A5 gene (AAV9/SLC13A5). Cerebrospinal fluid-delivery of AAV9/SLC13A5 decreased extracellular citrate levels, normalized electrophysiologic and sleep architecture abnormalities, and restored resistance to chemically induced seizures and death. Treatment benefits were achieved with administration during early brain development and in young adult mice, supporting a broad therapeutic window for this disorder. Comparison of delivery routes in young adult KO mice showed that higher brain targeting achieved with intra-cisterna magna delivery resulted in greater treatment benefit as compared to intrathecal lumbar puncture delivery. Together, these results support further development of AAV9/SLC13A5 for treating SLC13A5 citrate transporter disorder. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=90 SRC="FIGDIR/small/663044v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@ddc591org.highwire.dtl.DTLVardef@1d5e967org.highwire.dtl.DTLVardef@ce6c2forg.highwire.dtl.DTLVardef@209176_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2024

Multi-omic integration with human DRG proteomics highlights TNFα signalling as a relevant sexually dimorphic pathway

The peripheral nervous system (PNS) plays a critical role in pathological conditions, including chronic pain disorders, that manifest differently in men and women. To investigate this sexual dimorphism at the molecular level, we integrated quantitative proteomic profiling of human dorsal root ganglia (hDRG) and peripheral nerve tissue into the expanding omics framework of the PNS. Using data-independent acquisition (DIA) mass spectrometry, we characterized a comprehensive proteomic profile, validating tissue-specific differences between the hDRG and peripheral nerve. Through multi-omic analyses and in vitro functional assays, we identified sex-specific molecular differences, with TNF signalling emerging as a key sexually dimorphic pathway with higher prominence in males. Genetic evidence from genome-wide association studies (GWAS) further supports the functional relevance of TNF signalling in the periphery, while clinical trial data and meta-analyses indicate a sex-dependent response to TNF inhibitors. Collectively, these findings underscore a functionally sexual dimorphism in the PNS, with direct implications for sensory and pain-related clinical translation.

neuroscience↗

bioRxiv2020

Sexually divergent cortical control of affective-autonomic integration

Depression and cardiovascular disease reduce quality of life and increase mortality risk. These conditions commonly co-occur with sex-based differences in incidence and severity. However, the biological mechanisms linking the disorders are poorly understood. In the current study, we hypothesized that the infralimbic (IL) prefrontal cortex integrates mood-related behaviors with the cardiovascular burden of chronic stress. In a rodent model, we utilized optogenetics during behavior and in vivo physiological monitoring to examine how the IL regulates affect, social motivation, neuroendocrine-autonomic stress reactivity, and the cardiac consequences of chronic stress. Our results indicate that IL glutamate neurons increase socio-motivational behaviors specifically in males. IL activation also reduced endocrine and cardiovascular stress responses in males, while increasing reactivity in females. Moreover, prior IL stimulation protected males from subsequent chronic stress-induced sympatho-vagal imbalance and cardiac hypertrophy. Our findings suggest that cortical regulation of behavior, physiological stress responses, and cardiovascular outcomes fundamentally differ between sexes.

neuroscience↗

bioRxiv2020

Infralimbic cortical glutamate output is necessary for the neural and behavioral consequences of chronic stress

Exposure to prolonged stress is a major risk-factor for psychiatric disorders such as generalized anxiety and major depressive disorder (MDD). Human imaging studies have identified structural and functional abnormalities in the prefrontal cortex of MDD patients, particularly Brodmanns area 25 (BA25). Further, deep brain stimulation of BA25 reduces symptoms of treatment-resistant depression. The rat homolog of BA25 is the infralimbic cortex (IL), which is critical for cognitive appraisal, executive function, and physiological stress reactivity. Previous studies indicate that the IL undergoes stress-induced changes in excitatory/inhibitory balance culminating in reduced activity of glutamate output neurons. However, the regulatory role of IL glutamate output in mood-related behaviors after chronic variable stress (CVS) is unknown. Here, we utilized a lentiviral-packaged small-interfering RNA to reduce translation of vesicular glutamate transporter 1 (vGluT1 siRNA), thereby constraining IL glutamate output. This viral-mediated gene transfer was used in conjunction with a quantitative anatomical analysis of cells expressing the stable immediate-early gene product {Delta}FosB, which accumulates in response to repeated neural activation. Through assessment of {Delta}FosB-expressing neurons across the frontal lobe in adult male rats, we mapped regions altered by chronic stress and determined the coordinating role of the IL in frontal cortical plasticity. Specifically, CVS-exposed rats had increased density of {Delta}FosB-expressing cells in the IL and decreased density in the anterior insula. The later effect was dependent on IL glutamate output. Next, we examined the interaction of CVS and reduced IL glutamate output in behavioral assays examining coping, anxiety-like behavior, associative learning, and nociception. IL glutamate knockdown decreased immobility during the forced swim test compared to GFP controls, both in rats exposed to CVS as well as rats without previous stress exposure. Further, vGluT1 siRNA prevented CVS-induced avoidance behaviors, while also reducing risk aversion and passive coping. Ultimately, this study identifies the necessity of IL glutamatergic output for regulating frontal cortical neural activity and behavior following chronic stress. These findings also highlight how disruption of excitatory/inhibitory balance within specific frontal cortical cell populations may impact neurobehavioral adaptation and lead to stress-related disorders.

neuroscience↗