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Haem is an essential cofactor in central metabolic pathways in the vast majority of living systems. Prokaryotes acquire haem via haem biosynthesis pathways, and some also utilize haem uptake systems, yet it remains unclear how they balance haem requirements with the paradox that free haem is toxic. Here, using the model pathogen Staphylococcus aureus, we report that IsdG, one of two haem oxygenase enzymes in the haem uptake system, inhibits the formation of haem via the internal haem biosynthesis route. More specifically, we show that IsdG decreases the activity of ferrochelatase and that the two proteins interact both in vitro and in vivo. Further, a bioinformatics analysis reveals that a significant number of haem biosynthesis pathway containing organisms possess an IsdG-homologue and that those with both biosynthesis and uptake systems have at least two haem oxygenases. We conclude that IsdG-like proteins control intracellular haem levels by coupling the two pathways. IsdG is thus a target for the treatment of S. aureusinfections.
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http://dx.doi.org/10.1111/mmi.14060 | DOI Listing |
JCI Insight
September 2025
Division of Nephrology, Boston University Chobanian & Avedisian School of Medicine, Boston, United States of America.
Background: Active vitamin D metabolites, including 25-hydroxyvitamin D (25D) and 1,25-dihydroxyvitamin D (1,25D), have potent immunomodulatory effects that attenuate acute kidney injury (AKI) in animal models.
Methods: We conducted a phase 2, randomized, double-blind, multiple-dose, 3-arm clinical trial comparing oral calcifediol (25D), calcitriol (1,25D), and placebo among 150 critically ill adult patients at high-risk of moderate-to-severe AKI. The primary endpoint was a hierarchical composite of death, kidney replacement therapy (KRT), and kidney injury (baseline-adjusted mean change in serum creatinine), each assessed within 7 days following enrollment using a rank-based procedure.
J Clin Invest
September 2025
The University of Texas at Austin, Austin, United States of America.
Background: Following SARS-CoV-2 infection, ~10-35% of COVID-19 patients experience long COVID (LC), in which debilitating symptoms persist for at least three months. Elucidating biologic underpinnings of LC could identify therapeutic opportunities.
Methods: We utilized machine learning methods on biologic analytes provided over 12-months after hospital discharge from >500 COVID-19 patients in the IMPACC cohort to identify a multi-omics "recovery factor", trained on patient-reported physical function survey scores.
Gen Physiol Biophys
September 2025
Department of Neurology, Hubei Third People's Hospital of Jianghan University, Wuhan, China.
In this study, we investigated the therapeutic potential of calycosin (from Astragalus) in Alzheimer's disease (AD), focusing on ferroptosis modulation. APP/PS1 mice received 40 mg/kg calycosin for 3 months. Cognitive function was assessed via Morris water maze test.
View Article and Find Full Text PDFJ Integr Neurosci
August 2025
Central Laboratory, The First Affiliated Hospital of Henan Polytechnic University (Jiaozuo Second People's Hospital), 454001 Jiaozuo, Henan, China.
Background: Epilepsy, a significant neurological condition marked by the occurrence of repeated seizures, continues to pose a substantial health challenge. Previous studies have indicated that Dipeptidyl Peptidase-4 (DPP4) inhibitors may possess antiepileptic properties. Ferroptosis, a newly discovered type of programmed cell death, has recently surfaced as a promising therapeutic target in the management of epilepsy.
View Article and Find Full Text PDFSynth Syst Biotechnol
December 2025
Department of Pharmacy of the Fourth Affiliated Hospital and Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou, 310058, China.
Nitrogen-nitrogen (N-N) bond-forming enzymes are rare but play vital roles in both primary and secondary metabolism. Guided by a nitric oxide synthase (NOS)-based genome mining strategy, we report the discovery and characterization of a new heme-dependent enzyme system that catalyzes intermolecular N-N bond formation. Using both in vivo and in vitro reconstitution approaches, we demonstrated that a protein complex, comprising a heme enzyme and a 2[4Fe-4S] ferredoxin partner, mediates the coupling of the α-amine group of l-aspartate with inorganic nitrogen oxide species, such as nitrite or nitric oxide, to generate hydrazinosuccinic acid, a key biosynthetic precursor in several natural product pathways.
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