Search bioRxiv⌕ Search

bioRxiv · 10.1101/2022.04.19.488860

Activation of IP10/CXCR3 signaling with highly coincidental with PrPSc deposit in the brains of scrapie infected mice

Abstract

Activation of chemokine IP10, also named as CXCL10, and its receptor CXCR3 in CNS is described in some neurodegenerative diseases. Our previous study has also demonstrated an increased brain IP10 levels in several scrapie infected rodent models. However, the detailed alteration of IP10/CXCR3 signaling in CNS during prion infection remains unsettled. Here, we found the increased IP10 signals in the brains of scrapie infected mice mainly localized in the neurons and the activated microglia using various methodologies. The levels of CXCR3 were markedly increased in brains of the scrapie infected mice and in the prion infected cell line SMB-S15. The increased CXCR3 mainly distributed in neurons. Obviously morphological colocalizations of PrP/PrPSc with IP10 and CXCR3 in the brains of scrapie infected mice were observed in the assays of immunohistochemistry (IHC) and immunofluorescence. Additionally, IHC analysis with whole brain sections demonstrated that the increased IP10 and CXCR3 accumulated in the brain regions with more PrPSc deposits. Co-immunoprecipitation and biomolecular interaction assays identified the evidence for the molecular interactions of PrP with IP10 and CXCR3. Compared to the normal partner cell line SMB-PS, the more portion of IP10 accumulated insides of prion infected SMB-S15 cells. Removal of prion replication in SMB-S15 cells by resveratrol converted the pattern of the accumulation and secretion of cellular IP10. Our data here demonstrate an activation of IP10/CXCR3 signaling in the brain tissues of prion infection, highly coincidental with PrPSc deposit. Modulation of brain IP10/CXCR3 signaling is potential therapeutic target for reducing the progression of prion diseases.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

jia, C., Chen, c., chao, H., wei, Y., lin, W., dong, C. d., zhang, W. y., qi, S., ping, D. x.. 2022-04-20. Activation of IP10/CXCR3 signaling with highly coincidental with PrPSc deposit in the brains of scrapie infected mice. https://doi.org/10.1101/2022.04.19.488860

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

A systems-level model of sleep-dependent memory-consolidation failure in neurodegeneration: the spindle-slow-oscillation decoupling cascade dissociates amyloid and tau

During non-rapid-eye-movement (NREM) sleep, the temporal coupling of cortical slow oscillations (SOs), thalamic spindles, and hippocampal sharp wave ripples drives the consolidation of declarative memories. This coupling degrades in ageing and Alzheimers disease (AD), and although A{beta} and tau leave dissociable signatures in human sleep, the mechanisms by which progressive pathology dismantles the consolidation machinery are difficult to isolate experimentally, and have not to our knowledge been reproduced in a model that can be perturbed directly. We built a systems-level model in which cortical SOs and thalamic spindles are generated by reduced oscillators, hippocampal ripples replay encoded spike sequences, and the measured per-event SO-spindle timing alignment causally gates spike-timing dependent plasticity on cortical sequence synapses. A post-sleep cued-recall test reads out consolidation. Five neurodegeneration parameters (amyloid, tau, synaptic density, GABAergic inhibition, cholinergic tone) map to dis tinct mechanisms grounded in the human and animal literature. The model reproduces graded healthy consolidation and a progressive collapse in which coupling, slow-wave power, spindle power and recall fall monotonically and the overnight memory effect flips from consolidation to net forgetting, with weak memories failing first. Scrambling SO-spindle timing while holding oscillation power fixed abolishes consolidation, establishing that coupling timing, rather than oscillation power, is what the plasticity gate depends on within the model. A{beta} and tau impair memory through orthogonal signatures (A{beta} collapses slow-wave power while sparing replay order, tau the reverse) and this orthogonality holds across the entire A{beta} x tau plane and survives simultaneous {+/-}50% resampling of every mapping coefficient (40/40 samples), so it is not an artefact of a single calibration point. The model yields a falsifiable clinical prediction: closed-loop slow-oscillation enhancement rescues memory only when the deficit is amplitude/coupling-dominated, not when it is replay(tau)-dominated, despite normalising slow-wave power in both cases. Because the therapy arms dissociate coupling from memory benefit, the model also cautions against adopting SO-spindle coupling as a standalone surrogate endpoint.

neuroscience↗

Toxicity of MAPT 4R RNA Contributes to Motor Neuron Degeneration in ALS

MAPT (Tau) dysregulation is implicated in several neurodegenerative diseases, but its contribution to amyotrophic lateral sclerosis (ALS) is poorly understood. Here we show that mRNA isoforms encoding 4-repeat (4R) Tau are upregulated and cytoplasmically enriched in iPSC-derived motor neurons (MNs) from VCP-mutant and sporadic ALS, without a corresponding change in Tau protein. Using splice-switching antisense oligonucleotides and isoform-specific siRNAs, we find that enhanced 4R expression reduces MN viability, whereas its selective knockdown improves survival, with kinetics more consistent with an RNA-intrinsic effect than altered protein synthesis. Exon 10-containing MAPT RNA shows increased predicted secondary structure, self-association and altered Tau biocondensation in vitro. In post-mortem ALS cervical spinal cord, increased relative exon 10 usage is associated with a higher-risk clinical phenotype and shorter disease duration These findings identify an isoform-specific contribution of MAPT to MN vulnerability in ALS and nominate 4R MAPT RNA as a therapeutic target.

neuroscience↗

30 Hz High-Definition Transcranial Alternating Current Stimulation at the Left Frontal Cortex Reduces the Spectral Slope of the EEG in the Contralateral Hemisphere

Background: High-definition transcranial alternating current stimulation (HD-tACS) is favored by the neurostimulation community for its precision and ability to influence neuronal dynamics. Yet, the exact mechanism by which the underlying brain structures are being affected remains unclear. We believe that the investigation of the aperiodic nature of the electroencephalograph (EEG) could shed light on the modulatory effects of HD-tACS. Methods: We analyzed the EEG of 9 participants during a compensatory tracking task (CTT) in two sessions, each with different HD-tACS protocols. Every session consisted of an initial period of no stimulation, followed by 30 Hz HD-tACS in the left motor (M30) or frontal (F30) cortex. We then isolated the aperiodic component of the EEG and calculated its spectral slope {beta}. Results and Discussion: {beta} decreased during F30 mainly in the right frontal cortex, indicating a shift towards higher frequencies and an increase of the excitatory/inhibitory balance. Additionally, we found that despite the long monotonus task the accuracy of the participants did not decrease, which might be attributed to the ability of both M30 and F30 to sustain attention for prolonged time. Finally, the change of CTT accuracy during the stimulation correlated with the {beta} of specific channels before the stimulation. This indicates the potential of {beta} to be used as a screening biomarker in future studies. In conclusion, we showed the ability of HD-tACS to alter EEG aperiodic dynamics and paved the way for future exploration of such dynamics in the field.

neuroscience↗