Biology subjects

Lapi, S. E.

Publications and source records attributed to Lapi, S. E..

3 recordsLinked to original sources

bioRxiv2024

Oxidative Injury to Lung Mitochondrial DNA is a Key Contributorfor the Development of Chemical Lung Injury

The mechanisms and extent to which inhalation of oxidant gases damage the mitochondrial genome contributing to the development of acute and chronic lung injury have not been investigated. C57BL/6 mice exposed to chlorine (Cl2) gas and returned to room air, developed progressive loss of lung DNA glycosylase OGG1, significant oxidative injury to mtDNA, decreased intact lung mitochondrial (mt) DNA, generation of inflammatory pathway by DAMPs causing airway and alveolar injury with significant mortality. Global proteomics identified over 1400 lung proteins with alteration of key mitochondrial proteins at 24 h post Cl2 exposure. Intranasal instillation of a recombinant protein containing mitochondrial targeted OGG1 (mitoOGG1) post exposure, decreased oxidative injury to mtDNA, lung mitochondrial proteome, severity of the acute and chronic lung injury and increased survival. These data show that injury to the mt-genome is a key contributor to the development of acute and chronic lung injury.

physiology↗

bioRxiv2020

Radiolabeled Bacterial Metallophores as Targeted PET Imaging Contrast Agents for Accurate Identification of Bacteria and Outer Membrane Vesicles in vivo

Modern technologies such as 16s DNA sequencing capable of identifying microbes and provide taxonomic resolution at species and strain-specific levels is destined to be transformative1. Likewise, there is an emerging need to accurately identify both infectious and non-infectious microbes non-invasively in the body at the genus and species level to guide diagnosis and treatment strategies. Here, we report development of radiometal-labelled bacterial chelators, knowns as metallophores that allow non-invasive and selective imaging of bacteria and bacterial products in vivo. We show that these novel contrast agents are able to identify E. coli with strain level specificity and other bacteria, such as K. pneumoniae, based on expression of distinct cognate transporters on the bacterial surface. The probe is also capable of tracking probiotic, engineered bacteria and bacterial products, outer membrane vesicles (OMVs), in unique niches such as tumours. Moreover, we report that this novel targeted imaging approach has impactful applicability in monitoring antibiotic treatment outcomes in patients with pulmonary infections, thereby providing the ability to optimize individualized therapeutic approaches. Compared to traditional techniques used to manufacture probes, this strategy simplifies the process considerably by combining the function of metal attachment and cell recognition into a single molecule. Thus, we anticipate that these probes will be widely used in both clinical and investigative settings in living systems for non-invasive imaging of infectious and non-infectious organisms.

bioengineering↗

bioRxiv2019

RclA is a thermostable copper (II) reductase required for reactive chlorine resistance and host colonization in Escherichia coli.

Inflammatory bowel diseases (IBDs) are a growing health concern. Enterobacteria, including Escherichia coli, bloom to high levels in the gut during inflammation and strongly contribute to the pathology of IBDs. To survive in the inflamed gut, E. coli must tolerate high levels of antimicrobial compounds produced by the immune system, including toxic metals like copper and reactive chlorine oxidants like hypochlorous acid (HOCl). In this work, we show that the widely-conserved bacterial HOCl resistance enzyme RclA catalyzes the reduction of copper (II) to copper (I), and specifically protects E. coli against the combination of HOCl and intracellular copper, probably by preventing Cu(III) accumulation. E. coli lacking RclA were highly sensitive to HOCl and were defective in colonizing an animal host. Our results indicate unexpected complexity in the interactions between antimicrobial toxins produced by innate immune cells and suggest an important and previously unsuspected role for copper redox reactions during inflammation.

microbiology↗