Search bioRxiv⌕ Search

Biology subjects

Kress, M.

Publications and source records attributed to Kress, M..

10 recordsLinked to original sources

Inflammatory burning pain depends on a specific line of nociceptors

The development and persistence of burning pain and heat hyperalgesia following tissue injury and the subsequent inflammatory response, depend on the nuclear enzyme mitogen- and stress-activated kinase 1 (MSK1) expressed in a specific subset of transient receptor potential subfamily V member 1 (TRPV1)-expressing primary sensory neurons termed nociceptors, which are specialised for detecting harmful stimuli. Inflammation up-regulates and activates MSK1, and MSK1 governs TRPV1 expression in the MSK1 and TRPV1 co-expressing mouse and human nociceptors. Importantly, inhibition of inflammatory MSK1-mediated TRPV1 upregulation protects from heat hypersensitivity without affecting other relevant TRPV1 functions, such as the sensation of acute painful heat stimuli or the maintenance of the body core temperature. The newly discovered importance of the interaction between MSK1 and TRPV1 in a specific line of nociceptors provides mechanistic understanding of inflammatory pain and heat hyperalgesia pathogenesis.

neuroscience↗

Cariprazine modulates intrinsic excitability and network dynamics of hippocampal neurons in a cell-type dependent manner

Schizophrenia is a severe psychiatric disorder associated with altered dopaminergic signaling and hippocampal circuit dysfunction. Although antipsychotic medications remain the standard treatment, many are limited by incomplete efficacy and adverse effects. Cariprazine, a dopamine D2/D3 receptor partial agonist, has a favorable clinical profile, but its effects on neuronal excitability and network activity remain incompletely understood. Here, we integrated nationwide real-world clinical data with in vitro electrophysiology, computational modeling, and molecular analyses to define the neuronal actions of cariprazine. Among Hungarian patients diagnosed with schizophrenia and receiving index-drug monotherapy with one of the three prespecified D2/D3 targeting antipsychotics, haloperidol was associated with worse survival and a higher cumulative incidence of first registered suicide attempt than cariprazine or aripiprazole in matched observational cohorts. In primary mouse hippocampal cultures, multielectrode array recordings showed that acute cariprazine treatment moderately reduced spontaneous firing in a dose-dependent manner and prolonged burst intervals while largely preserving network synchronization. These effects were milder than those of haloperidol and aripiprazole. Whole-cell patch-clamp recordings revealed cell-type-dependent effects, with reduced intrinsic excitability and increased firing irregularity mainly in regular- and stuttering-type neurons. Conductance-based modeling identified enhanced Kv1-mediated D-type potassium currents as sufficient to reproduce these effects. Consistent with this mechanism, chronic cariprazine treatment altered Kv1.2 protein distribution without changing Kcna2/Kcna3 or Drd1/Drd2/Drd3 transcript expression. These findings identify modulation of intrinsic excitability via Kv1/D-type potassium currents as a candidate cellular mechanism of cariprazine and provide a translational link between real-world evidence and circuit-level drug effects.

neuroscience↗

Cell cycle-dependent mRNA localization in P-bodies

Understanding the dynamics of RNA targeting to membraneless organelles is essential to disentangle their functions. Here, we investigate how P-bodies (PBs) evolve during cell cycle progression. PB purification across the cell cycle uncovers widespread changes in their RNA content, which are partly uncoupled from cell cycle-dependent changes in RNA expression. Single molecule FISH shows various mRNA localization patterns in PBs peaking in G1, S, or G2, with examples illustrating the timely capture of mRNAs in PBs when their encoded protein becomes dispensable. Yet, rather than directly reflecting absence of translation, cyclic mRNA localization in PBs can be controlled by RBPs, such as HuR in G2, and by RNA features. Indeed, while PB mRNAs are AU-rich at all cell cycle phases, they are specifically longer in G1, possibly related to post-mitotic PB reassembly. Altogether, our study supports a model where PBs are more than a default location for excess untranslated mRNAs.

cell biology↗

Biophysical Essentials - A Full Stack Open-Source Software Framework for Conserved and Advanced Analysis of Patch-Clamp Recordings

Patch-Clamp recordings allow for in depth electrophysiological characterization of single cells, their general biophysical properties as well as characteristics of voltage- and ligand-gated ionic currents. Different acquisition modes, such as whole-cell patch-clamp recordings in the current or voltage clamp configuration, capacitance measurements or single channel recordings from cultured cells as well as acute brain slices are routinely performed for these purposes. Nevertheless, multipurpose transparent and adaptable software tools to perform reproducible state-of-the-art analysis of multiple experiment types and to manage larger sets of experimental data are currently unavailable. We therefore developed Biophysical Essentials (BPE) as an open-source python software for transparent and reproducible analysis of electrophysiological recordings. While initially designed to improve time consuming and repetitive analysis steps, BPE was optimized to cover entire workflows from data acquisition, preprocessing, visualization and normalization of single recordings up to stacked calculations and statistics of multiple experiments. BPE can operate with different file formats from different amplifier systems and producers. An in-process database logs all analysis steps for later review and serves as a central storage point for recordings. Statistical testing as well as advanced analysis functions like Boltzmann-fitting and dimensional reduction methods further support the researchers needs in projects involving electrophysiology techniques. Impact statementBiophysical Essentials provides fundamental support for transparent patch-clamp analysis to improve reproducibility in electrophysiology research.

neuroscience↗

IL-4 shaping glutamatergic synapse like structures for more mature iPSC derived neuron phenotypes

The prototypical pleiotropic anti-inflammatory cytokine IL-4 not only acts on immune cells but also has important roles in the nervous system mediating antinociception and neuroregeneration. Therefore, we explored the expression of IL-4, its receptors IL4RA and IL13RA1 and downstream signaling components together with morphological and functional assays as well as transcriptomic profiling in human nociceptors differentiating from induced pluripotent stem cells (iNocs). IL-4 induced de novo formation of synaptic boutons immunoreactive for vesicular glutamate transporter vGLUT1 in iNocs which express both, components of the IL-4 receptor complex (IL-4RA and IL-13RA1) and signaling machinery (Jak1/2, STAT6, PKC isoforms, translation factor EiF4E) during differentiation. Pharmacological inhibition of these translational or cellular signaling components reduced the synaptogenic effect. IL-4 induced distinct transcriptomic changes associated with biological process ontologies for "neuron projection development", "axonogenesis" and "synapse", "cellular process involved in reproduction in multicellular organism", "regulation of membrane potential" and "calcium ion transmembrane transport". This partially reflected injury-induced transcriptional changes of mouse nerve injury models which contribute to regenerative processes in peripheral nerve but possibly also to reconnecting primary afferent neurons to their projections in the spinal dorsal horn and indicates a critical role for IL-4 in the control of developing and established neuronal networks.

neuroscience↗

NOCICEPTRA2.0 - a comprehensive ncRNA atlas of human native and iPSC-derived sensory neurons

Non-coding RNAs (ncRNAs) play a critical role in regulating gene expression during development and in the pathogenesis of diseases. In particular, microRNAs have been extensively studied in the context of neurogenesis, the differentiation of pain sensing nociceptive neurons and the pathogenesis of pain disorder, however, little is known about the developmental signatures of other ncRNA species throughout sensory neuron differentiation. Moreover, there is currently no information available about the general expression signatures of ncRNAs in human dorsal root ganglia (DRGs) harboring the cell bodies of primary afferent nociceptors. To bridge this knowledge gap, we developed a comprehensive atlas of small ncRNA species signatures during the differentiation of human induced pluripotent stem cell (iPSC)-derived nociceptive neurons. By employing a combination of iPSC-derived sensory neuron and human DRG long and short RNA co-sequencing, we identified specific signatures that describe the developmental processes and the signatures of all currently known small ncRNA species in detail. Our analysis revealed that different ncRNA species, including tRNAs, snoRNAs, lncRNAs, and piRNAs, are associated with different stages of sensory neuron differentiation and maturation. We retrieved pronounced similarities in ncRNA expression between human DRG and late-stage iPSC-derived sensory neurons, which further supports the use of iPSC-derived sensory neurons to uncover functional and regulatory changes in ncRNAs and their suitability as a as a human model system to bridge the translational gap between preclinical findings mostly from rodent models and our understanding of human disorders for the development of mechanism-based treatments. In summary, our findings provide important insights into the role of ncRNA species other than microRNAs in human nociceptors. The updated NOCICEPTRA2.0 Tool will be the first fully comprehensive searchable ncRNA database for human sensory neurons enabling researchers to investigate important hub ncRNA regulators in nociceptors in full detail.

neuroscience↗

RNA at the surface of phase-separated condensates impacts their size and number

Membrane-less organelles, by localizing and regulating complex biochemical reactions, are ubiquitous functional subunits of intracellular organization. They include a variety of nuclear and cytoplasmic ribonucleoprotein (RNP) condensates, such as nucleoli, P-bodies, germ granules and stress granules. While is it now recognized that specific RNA and protein families are critical for the biogenesis of RNP condensates, how these molecular constituents determine condensate size and morphology is unknown. To circumvent the biochemical complexity of endogenous RNP condensates, the use of programmable tools to reconstitute condensate formation with minimal constituents can be instrumental. Here we report a methodology to form RNA-containing condensates in living cells with controlled RNA and protein composition. Our bioengineered condensates are made of ArtiGranule scaffolds undergoing liquid-liquid phase separation in cells and programmed to specifically recruit a unique RNA species. We found that RNAs localized on condensate surface, either as isolated RNA molecules or as a homogenous corona of RNA molecules around the condensate. This simplified system allowed us to demonstrate that the size of the condensates scales with RNA surface density, the higher the RNA density is, the smaller and more frequent the condensates are. Our observations suggest a mechanism based on physical constraints, provided by RNAs localized on condensate surface, that limit condensate growth and coalescence.

cell biology↗

NOCICEPTRA: Gene and microRNA signatures and their trajectories characterizing human iPSC-derived nociceptor maturation

Nociceptors are primary afferent neurons serving the reception of acute pain but also the transit into maladaptive pain disorders. Since native human nociceptors are hardly available for mechanistic functional research, and rodent models do not necessarily mirror human pathologies in all aspects, human iPSC-derived nociceptors (iDN) offer superior advantages as a human model system. Unbiased mRNA::microRNA co-sequencing, immunofluorescence staining and qPCR validations, revealed expression trajectories as well as miRNA target spaces throughout the transition of pluripotent cells into iDNs. mRNA and miRNA candidates emerged as regulatory hubs for neurite outgrowth, synapse development and ion channel expression. The exploratory data analysis tool NOCICEPTRA is provided as a containerized platform to retrieve experimentally determined expression trajectories, and to query custom gene sets for pathway and disease enrichments. Querying NOCICEPTRA for marker genes of cortical neurogenesis revealed distinct similarities and differences for cortical and peripheral neurons. The platform provides a public domain neuroresource to exploit the entire data sets and explore miRNA and mRNA as hubs regulating human nociceptor differentiation and function.

neuroscience↗

Fast holographic scattering compensation for deep tissue biologicalimaging

Scattering in biological tissues is a major barrier for in vivo optical imaging of all but the most superficial structures. Progress toward overcoming the distortions caused by scattering in turbid media has been made by shaping the excitation wavefront to redirect power into a single point in the imaging plane. However, fast, non-invasive determination of the required wavefront compensation remains challenging. Here, we introduce a quickly converging algorithm for non-invasive scattering compensation, termed DASH, in which holographic phase stepping interferometry enables new phase information to be updated after each measurement. This leads to rapid improvement of the wavefront correction, forming a focus after just one measurement iteration and achieving an order of magnitude higher signal enhancement at this stage than the previous state-of-the-art. Using DASH, we demonstrate two-photon fluorescence imaging of microglia cells in highly turbid mouse hippocampal tissue down to a depth of 530 m.

biophysics↗

GC content shapes mRNA decay and storage in human cells

Control of protein expression results from the fine tuning of mRNA synthesis, decay and translation. These processes, which are controlled by a large number of RNA-binding proteins and by localization in RNP granules such as P-bodies, appear often intimately linked although the rules of this interplay are not well understood. In this study, we combined our recent P-body transcriptome with various transcriptomes obtained following silencing of broadly acting mRNA decay and repression factors. This analysis revealed the central role of GC content in mRNA fate, in terms of P-body localization, mRNA translation and mRNA decay. It also rationalized why PBs mRNAs have a strikingly low protein yield. We report too the existence of distinct mRNA decay pathways with preference for AU-rich or GC-rich transcripts. Compared to this impact of the GC content, sequence-specific RBPs and miRNAs appeared to have only modest additional effects on their bulk targets. Altogether, these results lead to an integrated view of post-transcriptional control in human cells where most regulation at the level of translation is dedicated to AU-rich mRNAs, which have a limiting protein yield, whereas regulation at the level of 5 decay applies to GC-rich mRNAs, whose translation is optimal.

molecular biology↗