Biology subjects

Bruschi, M.

Publications and source records attributed to Bruschi, M..

4 recordsLinked to original sources

bioRxiv2026

Integrated metabolic and proteostatic profiling reveals remodeling of proteolytic pathways associated with redox-bioenergetic dysfunction in a PAHenu2 mouse model of phenylketonuria

Phenylketonuria (PKU) is a genetic metabolic disorder caused by the lack of functional phenylalanine hydroxylase (PAH). Elevated levels of phenylalanine (Phe) are known to be neurotoxic; however, the molecular mechanisms underlying Phes effects remain elusive. This study investigates the impact of PKU on proteostasis, redox balance, and metabolism in BTBR PAHenu2 mice, a severe disease animal model. Combined proteomics and metabolomics revealed impaired redox homeostasis in the brain and disrupted mitochondrial energy metabolism (ATP and TCA intermediates). The dysregulation was further supported by decreased levels of ATP, reduced glutathione (GSH), cysteine, and reduced catalase activity. Western blot analyses revealed substantial remodeling of protein degradation systems: the 19S regulatory (Rpt1) subunit and 26S proteasome content and activity were significantly increased, and ubiquitinated protein levels were elevated, indicating protein turnover and activation of the ubiquitin-proteasome system. Autophagy was also activated, as evidenced by a reduced LC3-II/LC3-I ratio, decreased p62 levels, unchanged ATG5 levels, and increased HSPA8 protein expression. By contrast, UPR markers remained stable despite an increase in the oxidized-to-reduced PDI ratio, suggesting a localized shift without activation of a full ER stress response. In parallel, systemic alterations were assessed in whole blood. Indeed, GSH, cysteine, ATP and ADP were decreased in PKU, whereas NADPH increased. These changes were accompanied by reduced activities of GSH reductase and GSH peroxidase, thereby confirming metabolic and redox disruption. Collectively, these findings indicate that PKU is associated with activation of protein degradation pathways as an adaptive response to cellular stress combined with redox imbalance and energy dysregulation. Highlights- Proteasome complex levels and activity were upregulated in PAHenu2 mouse brains - Autophagy was also enhanced in PAHenu2 mouse brains - Despite increased PDI oxidation, the Unfolded Protein Response was not activated - Redox and energy metabolism were disrupted in both brain and blood

molecular biology↗

bioRxiv2026

An N, S-acetylated L-cysteine-cysteamine conjugate hinders pyocyanin redox cycling to weaken Pseudomonas aeruginosa biofilm and dampens LPS-driven acute pulmonary inflammation

The persistence of P. aeruginosa infections is largely driven by the secretion of several factors during invasion, including the redox-active phenazine pyocyanin (PYO), which promotes biofilm formation and oxidative stress. Biofilms contribute to chronic infections and antibiotic resistance, limiting the efficacy of conventional therapies. We found that a synthetic compound, I-152, a conjugate of N-acetyl-L-cysteine (NAC) and S-acetylcysteamine (also known as S-acetyl-{beta}-mercaptoethylamine; SMEA), effectively restored colistin susceptibility against P. aeruginosa by altering biofilm nanomechanical properties. These perturbations in matrix integrity were associated with I-152s ability to hinder the phenazine redox cycle, shifting PYO to a reduced state as well as enabling S-conjugate formation. The compound decreased PYO accumulation in bacterial cultures and PYO-generated reactive oxygen species (ROS) in macrophage cells. Together with PYO, LPS is another driver of ROS-dependent inflammatory signaling in the host, which leads to an uncontrolled cytokine response and organ damage, especially in patients with cystic fibrosis. I-152 treatment downregulated the expression of LPS-induced inflammatory cytokines, i.e., IL-6 and TNF-, in bone marrow-derived macrophages (BMDM) isolated from transgenic CFTR-/- and CFTR+/+ mice. Consistently, I-152 partially counteracted the inflammatory response in the P. aeruginosa LPS-induced acute lung injury murine model. Taken together, these results support I-152 as an adjunctive treatment for P. aeruginosa respiratory infections through a dual mechanism: combating antimicrobial resistance in biofilms and dampening host inflammation in the respiratory system. HighlightsO_LII-152 potentiates colistin activity against P. aeruginosa by compromising the biofilm surface C_LIO_LII-152 rewires the pyocyanin (PYO) redox state and forms covalent adducts with it C_LIO_LIPYO accumulation and PYO-induced ROS generation in macrophages is impaired by I-152 C_LIO_LIEx vivo, I-152 dampens excessive pro-inflammatory response to P. aeruginosa LPS in CFTR-/- and CFTR+/+ BM-derived macrophages C_LIO_LII-152 (140 mg/Kg) attenuates LPS-driven inflammation and lung damage in CFTR+/+ mice C_LI

pharmacology and toxicology↗

bioRxiv2025

IgM hyposialylation drives podocyte injury in pediatric and young adult patients with podocytopathies.

IntroductionAltered immunoglobulin glycosylation has been implicated in antibody-mediated podocytopathies, yet the functional impact of IgM sialylation remains unclear. Previous evidence suggested that circulating cationic or hyposialylated IgM may contribute to podocyte injury in idiopathic nephrotic syndrome (iNS). MethodsSerum IgM from pediatric and young adult patients with podocytopathies, membranous nephropathy (MN), lupus nephritis (LN), and healthy controls were analyzed by lectin-based ELISA using a panel of six biotinylated lectins to detect terminal N-glycan residues. Among these, Sambucus nigra agglutinin (SNA) binds 2,6-linked sialic acid, and Ricinus communis agglutinin I (RCA-I) recognizes {beta}1,4-linked galactose. Serum levels of the 2,6-sialyltransferase ST6GAL1 and the sialidases neuraminidase-1 (NEU1) and neuraminidase-3 (NEU3) were quantified. Cultured human podocytes were exposed to patient-derived, control, or enzymatically modified IgM (desialylated/resialylated) and analyzed by confocal microscopy, quantitative proteomics, phosphoproteomics, and metabolic assays. ResultsIgM from patients with podocytopathies showed reduced SNA binding, which inversely correlated with proteinuria (r = -0.69, P < 0.0001) and with serum sialidases NEU1/NEU3 (r = -0.67/-0.59, P < 0.0001). In paired samples, SNA reactivity decreased during relapse and normalized in remission, indicating dynamic modulation with disease activity. ST6GAL1 was undetectable in all groups. In contrast, PLA2R1-positive MN, in which pathogenic antibodies target podocyte PLA2R1, displayed reduced RCA-I binding. Podocytes exposed to hyposialylated or desialylated IgM exhibited actin disorganization, loss of nephrin signal, increased lipid peroxidation, and decreased ATP synthesis. In contrast, resialylated IgM preserved morphology and metabolism comparable to controls. Proteomic and phosphoproteomic profiling revealed enrichment of MAPK, mTOR, AMPK, and cytoskeletal remodeling pathways. ConclusionsIgM hyposialylation, driven by extracellular sialidases up-regulation, correlates with disease activity and promotes oxidative stress, mitochondrial dysfunction, and cytoskeletal remodeling in podocytes, identifying immune glycan remodeling as a modifiable determinant of podocyte injury and a potential biomarker of disease activity. Translational StatementAltered glycosylation of circulating immunoglobulins is emerging as a key mechanism underlying glomerular injury. Here, we demonstrate that hyposialylated IgM, resulting from elevated serum sialidases NEU1 and NEU3, directly induces podocyte cytoskeletal disorganization, oxidative stress, and metabolic impairment. In contrast, enzymatic resialylation maintains podocyte morphology and function at levels indistinguishable from controls, indicating that sialic acid loss is a modifiable determinant of podocyte injury. Clinically, reduced IgM sialylation correlates with proteinuria and disease activity in idiopathic nephrotic syndrome, supporting its potential as a biomarker of relapse and remission. Targeting the sialidase-sialic acid pathway may therefore represent a promising strategy to preserve podocyte integrity and improve outcomes in antibody-negative podocytopathies.

pathology↗

bioRxiv2017

Process proteomics of beer reveals a dynamic proteome with extensive modifications

Modern beer production is a complex industrial process. However, some of its biochemical details remain unclear. Using mass spectrometry proteomics, we have performed a global untargeted analysis of the proteins present across time during nano-scale beer production. Samples included sweet wort produced by a high temperature infusion mash, hopped wort, and bright beer. This analysis identified over 200 unique proteins from barley and yeast, emphasizing the complexity of the process and product. We then used data independent SWATH-MS to quantitatively compare the relative abundance of these proteins throughout the process. This identified large and significant changes in the proteome at each process step. These changes described enrichment of proteins by their biophysical properties, and identified the appearance of dominant yeast proteins during fermentation. Altered levels of malt modification also quantitatively changed the proteomes throughout the process. Detailed inspection of the proteomic data revealed that many proteins were modified by protease digestion, glycation, or oxidation during the processing steps. This work demonstrates the opportunities offered by modern mass spectrometry proteomics in understanding the ancient process of beer production.

biochemistry↗