Biology subjects

Paul, O.

Publications and source records attributed to Paul, O..

5 recordsLinked to original sources

bioRxiv2025

Effect of external cues on clock-driven protection from Influenza A infection

Influenza and other respiratory viral pathogens are leading causes of mortality and morbidity. We previously demonstrated that circadian rhythms confer temporal protection from influenza infection. Here, we investigated whether this protection requires rhythmic function after the initial infection by manipulating environmental cycles. We demonstrate that disrupting environmental lighting cues within a critical window of vulnerability abrogates time-of-day specific protection. This poor outcome is mediated by a dysregulated immune response, evidenced by the accumulation of inflammatory monocytes and CD8+ cells in the lungs and a transcriptomic profile indicative of an exaggerated immune response. Disruption of the light cycle does not affect outcomes in a clock mutant, indicating that it acts by compromising endogenous timekeeping. Importantly, rhythmic meal timing mitigates the adverse effects of disrupted light cycles, suggesting that external cycling cues, which act through different body clocks, can substitute for each other. Our findings highlight the crucial interplay between environmental factors and endogenous clocks in shaping influenza outcomes, offering significant translational potential for improving the care of critically ill patients with respiratory viral infections.

immunology↗

bioRxiv2025

Role of IL10 signaling in the circadian control of host response to Influenza infection

We have previously demonstrated that the circadian clock regulates the host response to influenza A virus (IAV) infection, conferring a time-of-day-specific protection -infection at dawn resulted in a threefold increase in survival and reduced immunopathology compared to infection at dusk. While IL10 is well-known for its immunoregulatory function, its role in IAV remains unclear, with studies reporting both protective and detrimental effects. Given the diurnal rhythmicity of IL-10 receptor (Il10ra) expression in the lung, we investigated the contribution of IL-10 signaling to time-of-day-specific IAV protection. We found that blocking IL10 signaling abrogated the time of day protection, leading to increased immunopathology characterized by enhanced lymphocyte infiltration and global immune activation (transcriptomic analysis). Interestingly, while later, IL-10R blockade also eliminated the time-of-day difference in IAV outcomes, it improved the outcome of dusk-infected mice. Furthermore, natural killer (NK) cell depletion suppressed IL-10 levels in bronchoalveolar lavage, suggesting a role for NK cells in regulating IL-10 signaling. In conclusion, incorporating the circadian context has not only clarified the IL-10 role in IAV infection but also underscored the pivotal influence of circadian regulation on immune responses.

immunology↗

bioRxiv2024

Microbiota-derived inosine programs protective CD8+ T cell responses against influenza in newborns

The immunological defects causing susceptibility to severe viral respiratory infections due to early-life dysbiosis remain ill-defined. Here, we show that influenza virus susceptibility in dysbiotic infant mice is caused by CD8+ T cell hyporesponsiveness and diminished persistence as tissue-resident memory cells. We describe a previously unknown role for nuclear factor interleukin 3 (NFIL3) in repression of memory differentiation of CD8+ T cells in dysbiotic mice involving epigenetic regulation of T cell factor 1 (TCF 1) expression. Pulmonary CD8+ T cells from dysbiotic human infants share these transcriptional signatures and functional phenotypes. Mechanistically, intestinal inosine was reduced in dysbiotic human infants and newborn mice, and inosine replacement reversed epigenetic dysregulation of Tcf7 and increased memory differentiation and responsiveness of pulmonary CD8+ T cells. Our data unveils new developmental layers controlling immune cell activation and identifies microbial metabolites that may be used therapeutically in the future to protect at-risk newborns.

immunology↗

bioRxiv2021

Intracortical probe arrays with silicon backbone and microelectrodes on thin polyimide wings enable long-term stable recordings in vivo

ObjectiveRecording and stimulating neuronal activity across different brain regions requires interfacing at multiple sites using dedicated tools while tissue reactions at the recording sites often prevent their successful long-term application. This implies the technological challenge of developing complex probe geometries while keeping the overall footprint minimal, and of selecting materials compatible with neural tissue. While the potential of soft materials in reducing tissue response is uncontested, the implantation of these materials is often limited to reliably target neuronal structures across large brain volumes. ApproachWe report on the development of a new multi-electrode array exploiting the advantages of soft and stiff materials by combining 7-m-thin polyimide wings carrying platinum electrodes with a silicon backbone enabling a safe probe implantation. The probe fabrication applies microsystems technologies in combination with a temporal wafer fixation method for rear side processing, i.e., grinding and deep reactive ion etching, of slender probe shanks and electrode wings. The wing-type neural probes are chronically implanted into the entorhinal-hippocampal formation in the mouse for in vivo recordings of freely behaving animals. Main resultsProbes comprising the novel wing-type electrodes have been realized and characterized in view of their electrical performance and insertion capability. Chronic electrophysiological in vivo recordings of the entorhinal-hippocampal network in the mouse of up to 104 days demonstrated a stable yield of channels containing identifiable multi-unit and single-unit activity outperforming probes with electrodes residing on a Si backbone. SignificanceThe innovative fabrication process using a process compatible, temporary wafer bonding allowed to realize new Michigan style probe arrays. The wing-type probe design enables a precise probe insertion into brain tissue and long-term stable recordings of unit activity due to the application of a stable backbone and 7-m-thin probe wings provoking locally a minimal tissue response and protruding from the glial scare of the backbone.

neuroscience↗

bioRxiv2021

Multifunctional optrode for opsin delivery, optical stimulation, and electrophysiological recordings in freely moving rats

ObjectiveOptogenetics involves delivery of light-sensitive opsins to the target brain region, as well as introduction of optical and electrical devices to manipulate and record neural activity, respectively, from the targeted neural population. Combining these functionalities in a single implantable device is of great importance for a precise investigation of neural networks while minimizing tissue damage. ApproachWe report on the development, characterization, and in vivo validation of a multifunctional optrode that combines a silicon-based neural probe with an integrated microfluidic channel, and an optical glass fiber in a compact assembly. The silicon probe comprises an 11-m-wide fluidic channel and 32 recording electrodes (diameter 30 m) on a tapered probe shank with a length, thickness, and maximum width of 7.5 mm, 50 m, and 150 m, respectively. The size and position of fluidic channels, electrodes, and optical fiber can be precisely tuned according to the in vivo application. Main resultsWith a total system weight of 0.97 g, our multifunctional optrode is suitable for chronic in vivo experiments requiring simultaneous drug delivery, optical stimulation, and neural recording. We demonstrate the utility of our device in optogenetics by injecting a viral vector carrying a ChR2-construct in the prefrontal cortex and subsequent photostimulation of the transfected neurons while recording neural activity from both the target and adjacent regions in a freely moving rat. Additionally, we demonstrate a pharmacological application of our device by injecting GABA antagonist bicuculline in an anesthetized rat brain and simultaneously recording the electrophysiological response. SignificanceOur triple-modality device enables a single-step optogenetic surgery. In comparison to conventional multi-step surgeries, our approach achieves higher spatial specificity while minimizing tissue damage. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=154 SRC="FIGDIR/small/441836v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@11fa19org.highwire.dtl.DTLVardef@3ab5b6org.highwire.dtl.DTLVardef@6fe1b2org.highwire.dtl.DTLVardef@14a7bb3_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗