Search bioRxiv⌕ Search

bioRxiv · 10.1101/2025.02.05.635995

Loss of intestinal endosome associated protein sorting nexin 27 disrupts epithelial barrier and promotes inflammation

Abstract

Backgrounds and aimsSNX27, member of the sorting nexin (SNX) family, carries a unique PDZ domain and mediates recycling of endocytosed transmembrane proteins. SNX27 is critical for neurodevelopmental processes, however its role in intestine remains unexplored. We aim to determine the previously unknown roles of SNX27 in regulating intestinal homeostasis, epithelial barrier integrity, and inflammatory responses. MethodsWe used available datasets to analyze SNX27 expression in human IBD. We generated a novel mouse model of SNX27 conditional deletion from intestinal epithelial cells (SNX27{Delta}IEC) and challenged these mice with Dextran Sulfate Sodium (DSS). ResultsSNX27 expression was significantly lower in human IBD, including UC and CD. SNX27{Delta}IEC mice had significantly lower bodyweight and exhibited increased proliferation and poor differentiation of secretory Paneth and Goblet cells. We found reduced mucin layer and downregulation of crucial epithelial barrier proteins {Delta}-catenin, E-cadherin, ZO-1, and Claudin10 in SNX27{Delta}IEC mice. SNX27{Delta}IEC mice showed high intestinal permeability and spontaneously developed intestinal inflammation. Moreover, SNX27{Delta}IEC mice were more susceptible towards DSS-induced colitis, compared to the SNX27Loxp mice. ConclusionOverall, deletion of intestinal epithelial SNX27 weakens barrier functions and promotes inflammation. Our results indicate a novel role of SNX27 in regulating intestinal physiology and protecting against intestinal disorders. Thus, understanding the mechanisms of SNX27 downregulation in IBD will provide insights into new prevention and targets against chronic inflammation. SynopsisO_LISNX27 recycles internalized transmembrane proteins in the endocytic pathway. Human IBD showed reduced levels of SNX27. C_LIO_LISNX27 plays novel functions by maintaining intestinal homeostasis and inhibiting inflammation. C_LIO_LISNX27 protects the host against losing intestinal integrity during inflammation. C_LI

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Deb, S., Zhang, Y.-g., Xia, Y., Sun, J.. 2025-02-07. Loss of intestinal endosome associated protein sorting nexin 27 disrupts epithelial barrier and promotes inflammation. https://doi.org/10.1101/2025.02.05.635995

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

KEEP EXPLORING

Related preprints

Hypothalamic Farnesoid X Receptor deficiency alters energy balance by modulating hepatic glucose production and adipose tissue metabolism through central insulin signaling.

Objectives: The bile acid nuclear receptor Farnesoid X Receptor (FXR, NR1H4) is a major regulator of metabolism and energy homeostasis in peripheral organs. It modulates bile acid, glucose, and lipid metabolism, as well as fat mass and body weight. However, FXR is also expressed in the brain, particularly in the hypothalamus, a key center for the regulation of energy homeostasis. Although one study has demonstrated a role for brain FXR activation in energy balance, its specific hypothalamic role is still unknown. Here, we examined the role of FXR in the mediobasal hypothalamus in the regulation of energy balance. Methods: We used a genetic approach combined with metabolic phenotyping to determine the effect of FXR invalidation in the mediobasal hypothalamus on metabolic parameters involved in the central regulation of energy homeostasis. Results: Our results demonstrate that hypothalamic FXR deficiency induces a positive energy balance, resulting in a reduction in energy expenditure due to alterations in glucose metabolism accompanied by structural changes in white adipose tissues. Conclusion: This study uncovers a previously unrecognized role for hypothalamic FXR in the central homeostatic control of energy balance, providing new insights into its contribution to peripheral glucose metabolism and adipose tissue structural remodeling.

physiology↗

Rad and Phospholamban are Key Drivers of the Ventricular Adrenergic Response and Stress-Induced Arrhythmia

The adrenergic response is a fundamental mechanism that regulates heart rate (chronotropy), cardiac contractility (inotropy) and relaxation (lusitropy). Adrenergic stress is also a recognized trigger of arrhythmia in disease. Yet, our understanding of the underlying molecular basis remains incomplete. Protein kinase A (PKA) and the calcium/calmodulin-dependent kinase II (CaMKII) phosphorylate multiple targets proposed to participate in the adrenergic response, including the GTP-binding protein Rad, phospholamban (PLB) and ryanodine receptor 2 (RyR2). Here we demonstrate that phosphorylation of both Rad and PLB is necessary for inotropy and lusitropy. We show that changes in cardiac contractility and relaxation are primarily dependent on intracellular calcium handling. Finally, we report that Rad and PLB control stress-induced arrhythmogenesis, despite the phosphorylation of other pro-arrhythmic targets. We have identified the essential molecular components of the adrenergic response, resolving a long-standing debate in cardiac excitation-contraction coupling and refining current models of sympathetic regulation in health and disease.

physiology↗

Light-cycle time-restricted feeding remodels a hidden layer of the cardiac transcriptome through sex-specific transcript switching

Light-cycle time-restricted feeding disrupts daily cardiovascular and thermoregulatory rhythms, but the molecular effects of light-cycle time-restricted feeding on the heart have been measured only at the level of total gene expression. We used Oxford Nanopore long-read RNA sequencing to resolve the full-length ventricular transcriptome from male and female mice under ad libitum feeding or light-cycle time-restricted feeding across the 24-hour cycle. Greater than 20% of cardiac transcripts represent unannotated variants of known genes absent from the current GENCODE reference annotation. Light-cycle time-restricted feeding reorganizes transcript usage across hundreds of genes, including genes encoding splicing regulators, largely without changing total gene expression. The genes affected are sex-specific, with fewer than 2% of changes shared at the gene, transcript, and transcript-usage levels. We show that transcript-level regulation is a previously underrecognized component of the cardiac response to altered feeding behavior, undetected by conventional short-read approaches.

physiology↗