Biology subjects

Montrose, D. C.

Publications and source records attributed to Montrose, D. C..

5 recordsLinked to original sources

bioRxiv2026

Diet-derived peptides mediate the effects of dietary protein source on gastrointestinal health

Plant-based diets support gastrointestinal (GI) health while animal-based diets can disrupt gut homeostasis. Although multiple aspects of these diet types are believed to confer their respective effects, the role of their protein component is less well understood. Here, we conducted a randomized crossover-controlled feeding trial wherein healthy subjects consumed 70% of their daily protein intake in the form of pea protein (PP) or egg white protein (EWP) isolate (NCT05619939). Individuals who consumed EWP reported increased GI symptoms and exhibited elevated intestinal permeability. In contrast, these endpoints did not change following PP consumption. Fecal analysis showed increased diet-derived peptides only following EWP consumption, which was associated with resistance of EWP isolate to degradation by digestive enzymes in vitro. Metagenomic, metaproteomic and metabolomic analyses of stool after the EWP-based diet showed reduced abundance of multiple gut-protective bacterial species and increased bacterial amino acid utilization compared to samples following the PP-based diet. Dietary peptides in the gut luminal content of EWP-fed subjects reduced metabolic function of intestinal epithelial cell in culture. Providing an amino acid-based diet mimicking EWP composition to mice prevented colonic accumulation of diet-derived proteins and GI dysfunction associated with EWP diet consumption. Collectively, these findings demonstrate that dietary protein source is a key mediator of GI function, revealing a modifiable lifestyle factor that impacts human health.

physiology↗

bioRxiv2025

Dietary protein source mediates colitis pathogenesis through bacterial modulation of bile acids

Introductory paragraphEvidence-based dietary recommendations for individuals with inflammatory bowel diseases (IBD) are limited. Red meat consumption is associated with increased IBD incidence and relapse in patients, suggesting that switching to a plant-based diet may limit gut inflammation. However, the mechanisms underlying the differential effects of these diets remain poorly understood. Feeding diets containing plant- or animal-derived proteins to murine colitis models revealed that mice given a beef protein (BP) diet exhibited the most severe colitis, while mice fed pea protein (PP) developed mild inflammation. The colitis-promoting effects of BP were microbially-mediated as determined by bacterial elimination or depletion and microbiota transplant studies. In the absence of colitis, BP-feeding reduced abundance of Lactobacillus johnsonii and Turicibacter sanguinis and expanded Akkermansia muciniphila, which localized to the mucus in association with decreased mucus thickness and quality. BP-fed mice had elevated primary and conjugated fecal bile acids (BAs), and taurocholic acid administration to PP-fed mice worsened colitis. Dietary psyllium protected against BP-mediated inflammation, restored BA-modulating commensals and normalized BA ratios. Collectively, these data suggest that the protein component of red meat may be responsible, in part, for the colitis-promoting effects of this food source and provide insight into dietary factors that may influence IBD severity.

microbiology↗

bioRxiv2024

Deoxysphingolipids activate cGAS-STING in colon cancer cells and enhance tumor immunity

Deoxysphingolipids (deoxySLs) are a class of non-canonical sphingolipids that can adversely impact mitochondrial function. Mitochondrial disruption can activate the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING1) pathway, and in turn, promote antitumor immunity. Here, we investigated whether inducing deoxySL accumulation in colon cancer cells drives immune-specific, antitumor effects. We show that depleting serine increased deoxySLs and enhanced immune cell infiltration in colon tumors, in parallel with suppressing tumor growth. Elevating tumor deoxySL levels through mutation of SPT in cells and feeding a high alanine diet to mice exerted similar effects, including immune-mediated tumor growth suppression. Work conducted in multiple in vitro systems identified deoxySLs as key triggers of cGAS-STING1 activation, an effect mediated by mitochondrial release of double-stranded DNA resulting from mitochondrial stress. Collectively, these findings provide the first evidence that deoxySLs can drive antitumor immunity and identify a previously unrecognized metabolic strategy for cancer therapy.

cancer biology↗

bioRxiv2022

p53 engages the cGAS/STING cytosolic DNA sensing pathway for tumor suppression

Tumor suppression by p53 is known to involve cell autonomous and non-cell autonomous mechanisms. p53 has been shown to suppress tumor growth by modulating immune system functions, however, the mechanistic basis for this activity is not well understood. Here we report that p53 promotes the degradation of the DNA exonuclease TREX1, resulting in cytosolic dsDNA accumulation. We demonstrate that p53 requires the ubiquitin ligase TRIM24 to induce TREX1 ubiquitin-dependent degradation. The accumulation of cytosolic DNA due to p53s suppression of TREX1 activates the cytosolic DNA sensor, cGAS and its downstream effectors STING/TBK1/IRF3 resulting in induction of Type I interferons. TREX1 overexpression sufficed to block WTp53 activation of the cGAS/STING pathway. WTp53 mediated induction of type I interferon (IFNB1) response could be suppressed by cGAS/STING knockout. We find that p53s tumor suppressor activities are compromised by loss of signaling through the cGAS/STING pathway. Thus, our study reveals that p53 utilizes the cGAS/STING innate immune system pathway for both cell intrinsic and cell extrinsic tumor suppressor activities.

cancer biology↗

bioRxiv2020

Anti-tumor effects of an Id antagonist with no acquired resistance

Id proteins are helix-loop-helix (HLH) transcriptional regulators frequently overexpressed in cancer. Id proteins inhibit basic HLH transcription factors through protein-protein interactions, often inhibiting differentiation and sustaining proliferation. We recently identified a small-molecule, AGX51, which targets Id proteins for degradation and impairs ocular neovascularization in mouse models. Here we show that AGX51 treatment of cancer cell lines impaired cell growth and viability that results from a dramatic increase in ROS production upon Id degradation. In mouse models, AGX51 treatment suppressed breast cancer colonization in the lung, regressed the growth of paclitaxel-resistant breast tumors when combined with paclitaxel and reduced tumor burden in a model of sporadic colorectal neoplasia. Furthermore, in cells and mice, we failed to observe acquired resistance to AGX51 likely the result of the immutability of the binding pocket and efficient degradation of the Id proteins. Thus, AGX51 is a first-in-class compound that antagonizes Id proteins, shows strong anti-tumor effects and may be further developed for the management of multiple cancers.

cancer biology↗