Biology subjects

Remy, N.

Publications and source records attributed to Remy, N..

3 recordsLinked to original sources

bioRxiv2025

The phosphate exporter XPR1 regulates a gasdermin D-independent mature IL-1β secretion pathway in LPS-stimulated human monocytic cells

The inflammatory cytokine interleukin (IL)-1{beta} is a leaderless protein that is not secreted via the classical endoplasmic reticulum-Golgi pathway but instead is secreted during pyroptosis, a form of caspase-dependent inflammatory cell death mediated by gasdermin D (GSDMD) cleavage and pore formation at the plasma membrane. However, human monocytes can secrete IL-1{beta} in the absence of cell death, and the contribution of GSDMD in this secretory pathway is not established. Here, we identify two mechanisms of mature IL-1{beta} secretion by living human monocytic cells: a rapid, GSDMD-dependent pathway and a slower, GSDMD-independent pathway. Using a CRISPR-Cas9 loss-of-function screen, we identified XPR1 (Xenotropic and Polytropic retrovirus Receptor 1) as a key regulator of the GSDMD-independent pathway. XPR1 is the only phosphate exporter identified in metazoans and has no previously described function in cytokine secretion. XPR1 invalidation in GSDMD-/- monocytic cells impaired IL-1{beta} secretion. We further show that this regulatory function requires cell-surface expression of XPR1 and is linked to its phosphate export activity. Our results reveal a previously undescribed mechanism of IL-1{beta} secretion by living human monocytic cells, independent of GSDMD and unexpectedly linked to phosphate homeostasis. Deciphering this pathway could lead to new therapeutic modalities for IL-1{beta}-driven inflammatory diseases.

immunology↗

bioRxiv2025

Plant Cell Wall Enzymatic Hydrolysis: Predicting Yield Dynamics from Autofluorescence and Morphological Temporal Changes

Enzymatic hydrolysis of plant cell walls into fermentable sugars is a critical step in biotechnological conversion, yet efficiency is limited by cell wall recalcitrance. Predicting conversion yields of cell wall-derived sugars during hydrolysis is challenging due to the complex underlying mechanisms and the labor-intensive nature of conventional assays. This study introduces an innovative pipeline that accurately quantifies cell wall autofluorescence intensity and morphological descriptors during enzymatic hydrolysis. The pipeline incorporates a novel adaptive drift compensation strategy which dynamically adjusts to the progression and extent of deconstruction ensuring robust analysis. Applied to time-lapse images of spruce wood enzymatic deconstruction, the pipeline revealed strong negative correlations of conversion yields during hydrolysis with both the dynamics of cell wall autofluorescence intensity and morphological descriptors. Phase-specific analysis uncovered distinct correlation patterns dependent on hydrolysis stage and sugar type. This non-destructive pipeline eliminates the need for extensive sampling and time-consuming chemical assays, establishing plant cell wall autofluorescence and morphological descriptors as accurate predictive real-time biomarkers of dynamics of sugar conversion yields. The findings provide a framework for accelerating the development of optimized biotechnological conversion processes.

biochemistry↗

bioRxiv2024

A Distinct Autofluorescence Distribution Pattern Marks Enzymatic Deconstruction of Plant Cell Wall

Achieving an economically viable transformation of plant cell walls into bioproducts requires a comprehensive understanding of enzymatic deconstruction. Microscale quantitative analysis offers a relevant approach to enhance our understanding of cell wall hydrolysis, but becomes challenging under high deconstruction conditions. This study comprehensively addresses the challenges of quantifying the impact of extensive enzymatic deconstruction on plant cell wall at microscale. Investigation of highly deconstructed spruce wood provided spatial profiles of cell walls during hydrolysis with a remarkable precision. A distinct cell wall autofluorescence distribution pattern marking enzymatic hydrolysis along with an asynchronous impact of hydrolysis on cell wall structure, with cell wall volume reduction preceding cell wall accessible surface area decrease, were revealed. This study provides novel insights into enzymatic deconstruction of cell wall at under-investigated cell scale, and a robust computational pipeline applicable to diverse biomass species and pretreatment types for assessing hydrolysis impact and efficiency.

biochemistry↗