Biology subjects

Balana, A. T.

Publications and source records attributed to Balana, A. T..

3 recordsLinked to original sources

bioRxiv2025

The Secreted Metabolite Isopentenyladenine from Faecalibacterium prausnitzii Mitigates Gut Inflammation

Colonic microbiome dysbiosis is correlated with inflammatory bowel disease (IBD), and depletion of the commensal bacterium Faecalibacterium prausnitzii (F. prausnitzii) is routinely observed in the metagenomic analyses of IBD patient microbiome samples. F. prausnitzii is likely beneficial to hosts, as oral administration of F. prausnitzii strain A2-165 has anti-inflammatory properties in murine models of colitis. Previous studies attribute the anti-inflammatory effects of F. prausnitzii A2-165 to production of the short-chain fatty acid butyrate, as well as a 15 kDa protein known as microbial anti-inflammatory molecule (MAM). Here, we verified that oral dosing of strain A2-165 protects against DSS-induced murine colitis and further show the aqueous-soluble secreted fraction of overnight cultures from a collection of F. prausnitzii strain inhibit inflammatory signatures, including the activation of the hosts NF-{kappa}B pathway, production of IL-8, and differentiation of naive T cells into the TH17 lineage. We find that MAM is secreted in extracellular vesicles; however, MAM-containing vesicles do not have anti-inflammatory properties in our collection of assays and suggests that MAM is likely not a direct contributor. Untargeted and targeted mass spectrometry metabolomics analyses on the soluble anti-inflammatory secretome yielded several unique F. prausnitzii metabolites, including isopentenyladenine. We demonstrated isopentenyladenine independently modulates host cellular signaling and immune responses and suggests this newly identified metabolite with human immunomodulatory properties may be useful towards the discovery of IBD-focused therapeutics.

microbiology↗

bioRxiv2023

O-GlcNAc modification forces the formation of an α-Synuclein amyloid-strain with notably diminished seeding activity and pathology

The process of amyloid fibril formation remains one of the primary targets for developing diagnostics and treatments for several neurodegenerative diseases (NDDs). Amyloid-forming proteins such -Synuclein and Tau, which are implicated in the pathogenesis of Alzheimers and Parkinsons disease, can form different types of fibril structure, or strains, that exhibit distinct structures, toxic properties, seeding activities, and pathology spreading patterns in the brain. Therefore, understanding the molecular and structural determinants contributing to the formation of different amyloid strains or their distinct features could open new avenues for developing disease-specific diagnostics and therapies. In this work, we report that O-GlcNAc modification of -Synuclein monomers results in the formation of amyloid fibril with distinct core structure, as revealed by Cryo-EM, and diminished seeding activity in seeding-based neuronal and rodent models of Parkinsons disease. Although the mechanisms underpinning the seeding neutralization activity of the O-GlcNAc modified fibrils remain unclear, our in vitro mechanistic studies indicate that heat shock proteins interactions with O-GlcNAc fibril inhibit their seeding activity, suggesting that the O-GlcNAc modification may alter the interactome of the -Synuclein fibrils in ways that lead to reduce seeding activity in vivo. Our results show that post-translational modifications, such as O-GlcNAc modification, of -Synuclein are key determinants of -Synuclein amyloid strains and pathogenicity. These findings have significant implications for how we investigate and target amyloids in the brain and could possibly explain the lack of correlation between amyloid burden and neurodegeneration or cognitive decline in some subtypes of NDDs.

biochemistry↗

bioRxiv2019

O-GlcNAcylation of small heat shock proteins enhances their anti-amyloid chaperone activity

A major role for the intracellular posttranslational modification O-GlcNAc appears to be the inhibition of protein aggregation. Most of the previous studies in this area have focused on O-GlcNAcylation of the amyloid-forming proteins themselves. Here, we use synthetic protein chemistry to discover that O-GlcNAc also activates the anti-amyloid activity of certain small heat shock proteins (sHSPs), a potentially more important modification event that can act broadly and substoichiometrically. More specifically, we find that O-GlcNAcylation increases the ability of sHSPs to block the amyloid formation of both -synuclein and A{beta}. Mechanistically, we show that O-GlcNAc near the sHSP IXI-domain prevents its ability to intramolecularly compete with substrate binding. Our results have important implications for neurodegenerative diseases associated with amyloid formation and potentially other areas of sHSP biology.

biochemistry↗