Biology subjects

Matalon, S.

Publications and source records attributed to Matalon, S..

8 recordsLinked to original sources

bioRxiv2026

Mitochondria-Targeted OGG1 remodels Alveolar Epithelial Transitional States and Immune-Epithelial Communication after Chlorine Lung Injury

Chlorine (Cl2) inhalation causes acute epithelial and endothelial injury, pulmonary edema, inflammation, and impaired gas exchange, yet no approved therapy directly targets the mechanisms that sustain lung injury after exposure. We recently showed that oxidative mitochondrial DNA (mtDNA) damage drives chlorine-induced lung injury and that post-exposure delivery of a fusion protein containing mitochondria-targeted 8-oxoguanine DNA glycosylase-1 (mOGG1) mitigates lung injury and improves survival. However, the cell populations and transcriptional states through which mtDNA injury shapes lung damage and repair remain unclear. Here, we used single-nucleus RNA sequencing to define early cellular responses to distinct epithelial and immune cell populations. C57BL/6 mice (4/group; 2 males and 2 females per group) were exposed to air or Cl2 (500 ppm, 30 min), returned them to room air and mOGG1 (1 mg/kg, intranasal) was administered 1 h after exposure; the mice were sacrifice and their lungs were collected at 24 h post exposure. Integrated analysis resolved 39 transcriptionally distinct epithelial, immune, endothelial, stromal, and vascular populations. Although the major cellular compartments remained broadly preserved, Cl2 induced marked remodeling of epithelial composition and transcriptional states. Subclustering of the AT1/AT2 transitional compartment identified four Differential Transcriptomic Adaptation Phases (DTAPs): an acute stress-response state (DTAP_D), a proliferative state (DTAP_P), a Krt8 damage-associated transitional state (DTAP_T), and an AT1-like resolution state (DTAP_A). Pseudotemporal analyses suggested that chlorine exposure increased heterogeneity in alveolar and airway epithelial states, with injury-associated transitional programs expanding along the inferred trajectories. Ligand-receptor analysis further predicted that Cl2 increased the complexity of IL-1 communication among neutrophils, macrophages, and epithelial populations. mOGG1 did not globally suppress this network but instead redistributed signaling interactions, including the participation of selected DTAP populations. Together, these findings identify heterogeneous epithelial transitional states associated with Cl2 injury and support a model in which mOGG1 promotes recovery by reshaping epithelial injury-repair programs and immune-epithelial communication. Keywords: Chlorine inhalation; mitochondrial DNA damage; mitoOGG1; single-nucleus RNA sequencing; alveolar epithelial repair; epithelial transitional states; epithelial-immune communication.

molecular biology↗

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↗

bioRxiv2023

Hemopexin Reverses Activation of Lung eIF2a and Decreases Mitochondrial Injury in Chlorine Exposed Mice

We assessed the mechanisms by which non-encapsulated heme, released in the plasma of mice post exposure to chlorine (Cl2) gas, resulted in the initiation and propagation of acute lung injury. We exposed adult C57BL/6 male and female to Cl2 (500 ppm for 30 min) in environmental chambers and returned them to room air and injected them intramuscularly with a single dose of human hemopexin (hHPX; 5 {micro}g/ g BW), the most efficient scavenger of heme, 30-60 min post exposure. Concentrations of hHPX in plasma of air and Cl2 exposed mice were 9081{+/-}900 vs. 1879{+/-} 293 at 6 h and 2966{+/-}463 vs. 1555{+/-}250 at 50 h post injection (ng/ml; X{+/-}1 SEM=3; p<0.01). Cl2 exposed mice developed progressive acute lung injury post exposure characterized by increased concentrations of plasma heme, marked inflammatory response, respiratory acidosis and increased concentrations of plasma proteins in the alveolar space. Injection of hHPX decreased the onset of acute lung injury at 24 h post exposure; mean survival, for the saline and hHPX groups were 40 vs. 80% (P<0.001) at 15 d post exposure. Non-supervised global proteomics analysis of mouse lungs at 24 h post exposure, revealed the upregulation of 92 and downregulation of 145 lung proteins. Injection of hHPX at one h post exposure moderated the Cl2 induced changes in eighty-three of these 237 lung proteins. System biology analysis of the global proteomics data showed that hHPX reversed changes in mitochondrial dysfunction and elF2 and integrin signaling. Western blot analysis of lung tissue showed significant increase of phosphorylated elF2 at 24 h post exposure in vehicle treated mice but normal levels in those injected with hHPX. Similarly, RT-PCR analysis of lung tissue showed that hHPX reversed the onset of mtDNA lesions. A form of recombinant human hemopexin generated in tobacco plants was equally effective in reversing acute lung and mtDNA injury. The results of this study offer new insights as to the mechanisms by which exposure to Cl2 results in acute lung injury and to the therapeutic effects of hemopexin.

physiology↗

bioRxiv2022

Low Molecular Weight Hyaluronan Inhibits Lung Epithelial Ion Channels by Activating Calcium-Sensing Receptor

Herein, we tested the hypothesis low molecular weight hyaluronan (LMW-HA) inhibits lung epithelial ion transport in-vivo, ex-vivo, and in-vitro by activating the calcium-sensing receptor (CaSR). Intranasal instillation of LMW-HA (150g/ml) to C57BL/6 mice inhibited their alveolar fluid clearance (AFC) by 75%, increased the epithelial lining fluid (ELF) thickness threefold, and lung wet/dry (W/D) ratio by 20% 24hrs later. Incubation of lung slices from mouse and human lungs with 150g/ml LMW-HA decreased the open probability (Po) of ENaC in ATII cell by more than 50% in 4hrs, inhibited amiloride sensitive short circuit current (SCC) 4hrs post exposure, and Cl- current through CFTR by more than 70%, and Na,K-ATPase current by 66% at 24hrs. In all cases the inhibitory effect of LMW-HA on lung epithelial ion transport in vivo, ex vivo, and in vitro preparations were reversed by the administration of 1M of NPS2143, a CaSR inhibitor, or 150g/ml HMW-HA. In HEK-293 cells co-transfected with CaSR and the calcium sensitive Cl- channel TMEM16-A, LMW-HA activated an inward Cl- current. These data are the first demonstration of the inhibitory effects of LMW-HA on lung epithelial ion and water transport, and are due to the activation of CaSR and its downstream signaling cascades.

physiology↗

bioRxiv2022

The SARS-CoV-2 Spike S1 Protein Induces Global Proteomic Changes in ATII-Like Rat L2 Cells that are Attenuated by Hyaluronan

The COVID-19 pandemic continues to impose a major impact on global health and economy since its identification in early 2020, causing significant morbidity and mortality worldwide. Caused by the SARS-CoV-2 virus, along with a growing number of variants that have been characterized to date, COVID-19 has led to 571,198,904 confirmed cases, and 6,387,863 deaths worldwide (as of July 15th, 2022). Despite tremendous advances in our understanding of COVID19 pathogenesis, the precise mechanism by which SARS-CoV2 causes epithelial injury is incompletely understood. In this current study, robust application of global-discovery proteomics applications combined with systems biology analysis identified highly significant induced changes by the Spike S1 protein of SARS-CoV-2 in an ATII-like Rat L2 cells that include three significant network hubs: E2F1, CREB1/ RelA, and ROCK2/ RhoA. Separately, we found that pre-treatment with High Molecular Weight Hyaluronan (HMW-HA), greatly attenuated the S1 effects. Immuno-targeted studies carried out on E2F1 and Rock2/ RhoA induction and kinase-mediated activation, in addition to cell cycle measurements, validated these observations. Taken as a whole, our discovery proteomics and systems analysis workflow, combined with standard immuno-targeted and cell cycle measurements revealed profound and novel biological changes that contribute to our current understanding of both Spike S1 and Hyaluronan biology. This data shows that the Spike S1 protein may contribute to epithelial injury induced by SARS-CoV-2. In addition, our work supports the potential benefit of HMW-HA in ameliorating SARS CoV2 induced cell injury.

systems biology↗

bioRxiv2020

Heme Attenuates Endogenous Opioid Levels in Leukocytes of HIV positive individuals with Chronic Widespread Pain

ABSTRACTThe prevalence of chronic widespread pain (CWP) in people with HIV (PWH) is high, yet the underlying mechanisms are elusive. Leukocytes synthesize the endogenous opioid, β-endorphin (β-END), within their endoplasmic reticulum (ER). When released into plasma, β-END dampens nociceptive transmission by binding to opioid receptors on sensory neurons. In the present study, we hypothesized that heme-induced ER stress attenuates leukocyte levels/release of β-END, thereby increasing pain sensitivity in PWH. Results demonstrate that PWH with CWP have fragile erythrocytes, high plasma levels of cell-free heme, and impaired heme metabolism. Leukocytes from PWH with CWP also had high ER stress and low β-END compared to PWH without CWP and HIV-negative individuals with or without pain. In vitro heme exposure decreased β-END levels/secretion in murine monocytes/macrophages, which was prevented by treatment with sodium 4-phenylbutyrate, an ER stress inhibitor. To mimic hemolytic effects in a preclinical model in vivo, C57BL/6 mice were injected with phenylhydrazine hydrochloride (PHZ). PHZ increased cell-free heme and ER stress, decreased leukocyte β-END levels and hindpaw mechanical sensitivity thresholds. Treatment of PHZ-injected mice with the heme scavenger, hemopexin, blocked these effects, suggesting that heme-induced ER stress and a subsequent decrease in leukocyte β-END may contribute to CWP in PWH.Competing Interest StatementThe authors have declared no competing interest.View Full Text

pathology↗

bioRxiv2020

Heme Impairs Alveolar Epithelial Sodium Channels Post Toxic Gas Inhalation

We previously reported that cell-free heme (CFH) is increased in the plasma of patients with acute and chronic lung injury and causes pulmonary edema in animal model of acute respiratory distress syndrome (ARDS) post inhalation of halogen gas. However, the mechanisms by which CFH causes pulmonary edema are unclear. Herein we report for the first time the presence of CFH and chlorinated lipids (formed by the interaction of halogen gas, Cl2, with plasmalogens) in the plasma of patients and mice exposed to Cl2 gas. Ex vivo incubation of red blood cells (RBC) with halogenated lipids caused oxidative damage to RBC cytoskeletal protein spectrin, resulting in hemolysis and release of CFH. A single intramuscular injection of the heme-scavenging protein hemopexin (4 {micro}g/kg body weight) in mice, one hour post halogen exposure, reversed RBC fragility and decreased CFH levels to those of air controls. Patch clamp and short circuit current measurements revealed that CFH inhibited the activity of amiloride-sensitive (ENaC) and cation sodium (Na+) channels in mouse alveolar cells and trans-epithelial Na+ transport across human airway cells with EC50 of 125 nM and 500 nM, respectively. Molecular modeling identified 22 putative heme-docking sites on ENaC (energy of binding range: 86-1563 kJ/mol) with at least 2 sites within its narrow transmembrane pore, potentially capable of blocking Na+ transport across the channel. In conclusion, results suggested that CFH mediated inhibition of ENaC activity may be responsible for pulmonary edema post inhalation injury.

physiology↗

bioRxiv2019

Phosgene Inhalation Causes Hemolysis and Acute Lung Injury

Phosgene (Carbonyl Chloride, COCl2) remains an important chemical intermediate in many industrial processes such as combustion of chlorinated hydrocarbons and synthesis of solvents (degreasers, cleaners). It is a sweet smelling gas, and therefore does not prompt escape by the victim upon exposure. Supplemental oxygen and ventilation are the only available management strategies. This study was aimed to delineate the pathogenesis and identify novel biomarkers of acute lung injury post exposure to COCl2 gas. Adult male and female C57BL/6 mice (20-25 g), exposed to COCl2 gas (10 or 20ppm) for 10 minutes in environmental chambers, had a dose dependent reduction in PaO2 and an increase in PaCO2, 1 day post exposure. However, mortality increased only in mice exposed to 20ppm of COCl2 for 10 minutes. Correspondingly, these mice (20ppm) also had severe acute lung injury as indicated by an increase in lung wet to dry weight ratio, extravasation of plasma proteins and neutrophils into the bronchoalveolar lavage fluid, and an increase in total lung resistance. The increase in acute lung injury parameters in COCl2 (20ppm, 10min) exposed mice correlated with simultaneous increase in oxidation of red blood cells (RBC) membrane, RBC fragility, and plasma levels of cell-free heme. In addition, these mice had decreased plasmalogen (plasmenylethanolamine) and elevated levels of their breakdown product, polyunsaturated lysophosphatidylethanolamine, in the circulation suggesting damage to cellular plasma membranes. This study highlights the importance of free heme in the pathogenesis of COCl2 lung injury and identifies plasma membrane breakdown product as potential biomarkers of COCl2 toxicity.

physiology↗