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Research Interests

Cellular and physiological sequelae of oxidant injury to the mammalian blood-gas barrier; cellular and molecular mechanisms of active and passive solute transport across the alveolar epithelium; modulation of gene transfer by reactive oxygen and nitrogen species.

ACTIVE GRANTS

PREVENTION AND TREATMENT OF CHLORINE GAS INDUCED LUNG INJURY TO THE PULMONARY SYSTEM
5U01ES015676-04
PI: MATALON, SADIS

Abstract: Chlorine (C12) is a moderately soluble, highly reactive oxidant gas, used extensively for water purification, manufacturing of Pharmaceuticals and chemicals and as a potent disinfectant. Persons exposed to chlorine gas, may experience mild symptoms for the first 6-24 hours (h). However, following this latency period, severe lung injury, characterized by protein-rich edema and the onset of hypoxemia may develop. Presently, the cellular and biochemical events leading to this injury have not been elucidated. We propose that reactive oxygen-chloride and nitrogen intermediates (RONS), formed by the interaction of C12 and its hydrolysis products with nitric oxide (NO), initiate self-propagating chain reactions, the products of which damage alveolar epithelial cells decreasing their ability to produce and secrete surfactant, actively transport sodium (Na+) ions and maintain a tight, semi-permeable barrier. Thus, systemic administration of reactive species scavengers (such as ascorbate, N-acetyl-cysteine (NAC), and deferoxamine, as well as agents that augment surfactant levels, ion transport and paracellular resistance (such as albuterol (a long acting b-agonist) and a recently described peptide based on the lectin region of TNFa (tip peptide), shortly after exposure to C12 will decrease lung injury, morbidity and mortality. This hypothesis will be tested by exposing either confluent monolayers of rat alveolar type II (ATII) epithelial cells (SPECIFIC AIM # 1) or rats (SPECIFIC AIMS #2) to C12 (50-200 ppm for 30 min) and measure the following indices at 0.5, 6, 12 and 24 h post exposure: physiological and biochemical indices of lung function (including surfactant function and composition), ability of the lungs to transport ions in vivo and in vitro and clear pulmonary edema in vivo, levels of inflammatory cytokines in the rat alveolar space and in the plasma, arterial blood gases and pH, as well as levels of low reactive species scavengers (ascorbate, NAC) at 0.5, 6, 12, 24 and 48 h post exposure. These measurements will be repeated following intravenous injections of NAC, ascorbate and deferoxamine as well as albuterol and the tip peptide, every 6 h post exposure for 48 h. In SPECIFIC AIM #3 , we will assess the efficacy of intratracheally instilled ascorbate, NAC, deferoxamine, Infasurf (a surfactant replacement mixture), albuterol and the tip peptide, as well as aerosolized albuterol, in prolonging survival of rats with respiratory failure post C12 exposure. The subject matter of this research is both timely and important: more than 25 million tons of chlorine is manufactured annually in the United States and the majority of this gas is transported by rail and can be used as a chemical weapon.
 

MECHANISMS OF ENAC INHIBITION BY REPLICATING INFLUENZA VIRUS: ROLE OF M2 PROTEIN
2R01HL031197-24A1
PI: MATALON, SADIS

Abstract: Influenza (flu) is a contagious respiratory illness caused by flu viruses, leading to about 36,000 deaths every year in the United States alone, with the potential for at least a ten fold increase in epidemic and pandemic scenarios. During attachment of flu viruses to epithelial cells, hemagglutinin, one of its surface proteins, binds to sialic acid residues, initiating a series of events leading to activation of PKC, which in turn, down-regulates the activity of amiloride sensitive epithelial Na+ channels (ENaC) of tracheal and alveolar cells. It has been thought that these events are responsible for flu-induced rhinorrhea and life-threatening alveolar edema in humans. However, events occurring during the attachment of influenza virus to epithelial cells are likely to be transient and relatively few cells will be initially affected. We propose that M2, a transmembrane protein that plays a critical role in viral replication, enhances intracellular production of reactive oxygen-nitrogen species (RONS) which (i) oxidize and nitrate ENaC; and (ii) activate PKC(. Both processes enhance ENaC ubiquitination and subsequent destruction by the proteasome or lysosome systems. These hypotheses will be tested by completing the following comprehensive in vitro and in vivo studies listed in four specific aims: (1) Identify regions and specific amino acids of the influenza strain A/Udorn/72 M2 proton (H+) channel responsible for ENaC down-regulation in Xenopus oocytes microinjected with 1-,2-, and 3-ENaC. (2) Identify the mechanisms by which M2 decreases ENaC protein levels and function. We propose that M2 enhances intracellular production of reactive oxygen-nitrogen species (RONS) which (i) oxidize and nitrate ENaC; and (ii) activate PKC(. Both processes enhance ENaC ubiquitination and subsequent destruction by the proteasome or lysosome systems (3) Identify the mechanisms by which M2 inhibits amiloride sensitive Na+ currents in human airway (H441) and rat alveolar type II (rATII) cells, expressing native ENaC and (4) Establish the contribution of M2 in the inhibition of lung fluid clearance of mice infected by replicating flu viruses and identify the mechanisms involved. The results of our studies may provide the rational basis for the development of new therapeutic strategies, against a highly conserved region of the viral genome to knockdown M2 expression, and thus broadly and effectively decrease flu induced pulmonary edema and rhinorrhea. Due to the public health impact of influenza, there is a strong need to investigate and develop therapies that address the host response to viral infection, which may contribute to the morbidity and mortality of pathogenic respiratory viruses. PUBLIC HEALTH RELEVANCE: The results of our studies will provide the rational basis for the development of new therapeutic strategies, such as administration of agents to decrease M2 expression, and thus broadly and effectively decrease the flu-induced rhinorrhea, alveolar edema and hypoxemia. Due to the public health impact of influenza, there is a strong need to investigate and develop therapies that address the host response to viral infection, which may contribute to the morbidity and mortality of pathogenic respiratory viruses.

NOVEL TREATMENTS OF CHLORINE INDUCED INJURY TO THE CARDIO-RESPIRATORY SYSTEMS-U54
5U54ES017218-02
DIRECTOR/PI: MATALON, SADIS

Abstract: This Research Center of Excellence (RCE) entitled: "Novel Treatments of Chlorine Induced Injury to the Cardio-Respiratory Systems" consists of three projects and two cores. The unifying theme spanning all projects is that exposure of animals to C12 results in the formation of reactive intermediates which deplete ascorbate and reduced glutathione in the lung epithelial fluids, damage key components of the respiratory and alveolar epithelial [such as transient receptor protein (TRP) and epithelial sodium channels (ENaC)] and then, via inhibition of eNOS signaling compromise seminal functions of the pulmonary and systemic vasculatures. Furthermore, we propose that these toxic effects of C12 will be heightened in animals infected with respiratory syncytial virus or challenged with ova albumin. In our first series of experiments we will perform a number of state of the art biochemical, biophysical, physiological and morphometric measurements in RSV infected and ova albumin challenged mice as well as normal rats prior to and following C12 exposure to document the onset and progression of injury to lung epithelia and pulmonary and systemic vasculature. We will then treat them with antioxidants, TRP antagonists, /32 agonists and nitrite administered at various intervals post C12 exposure either intra-tracheally or via aerosolization or intraperitoneally (antioxidants and nitrite) and quantify recovery by specific functional measurements. Strong points of the RCE include the diverse talents of the investigators, the unique facilities, and the novelty of the preliminary data. The three projects (two of which build on novel findings generated by existing UO1 grants) are supported by an administrative core and the exposure core, which play key roles by both providing essential functions (such as exposure of animals to C12) and helping to integrate the team into a cohesive entity.

Administrative Supplement (NIH/NIEHS “Prevention and Treatment of Chlorine Induced Injury to the Pulmonary System
3U01ES015676-04S1
PI: MATALON, SADIS

Chlorine (C12) is a moderately soluble, highly reactive oxidant gas, used extensively for water purification, manufacturing of Pharmaceuticals and chemicals and as a potent disinfectant. Persons exposed to chlorine gas, may experience mild symptoms for the first 6-24 hours (h). However, following this latency period, severe lung injury, characterized by protein-rich edema and the onset of hypoxemia may develop. Presently, the cellular and biochemical events leading to this injury have not been elucidated. We propose that reactive oxygen-chloride and nitrogen intermediates (RONS), formed by the interaction of C12 and its hydrolysis products with nitric oxide (NO), initiate self-propagating chain reactions, the products of which damage alveolar epithelial cells decreasing their ability to produce and secrete surfactant, actively transport sodium (Na+) ions and maintain a tight, semi-permeable barrier. Thus, systemic administration of reactive species scavengers (such as ascorbate, N-acetyl-cysteine (NAC), and deferoxamine, as well as agents that augment surfactant levels, ion transport and paracellular resistance (such as albuterol (a long acting b-agonist) and a recently described peptide based on the lectin region of TNFa (tip peptide), shortly after exposure to C12 will decrease lung injury, morbidity and mortality. This hypothesis will be tested by exposing either confluent monolayers of rat alveolar type II (ATII) epithelial cells (SPECIFIC AIM # 1) or rats (SPECIFIC AIMS #2) to C12 (50-200 ppm for 30 min) and measure the following indices at 0.5, 6, 12 and 24 h post exposure: physiological and biochemical indices of lung function (including surfactant function and composition), ability of the lungs to transport ions in vivo and in vitro and clear pulmonary edema in vivo, levels of inflammatory cytokines in the rat alveolar space and in the plasma, arterial blood gases and pH, as well as levels of low reactive species scavengers (ascorbate, NAC) at 0.5, 6, 12, 24 and 48 h post exposure. These measurements will be repeated following intravenous injections of NAC, ascorbate and deferoxamine as well as albuterol and the tip peptide, every 6 h post exposure for 48 h. In SPECIFIC AIM #3 , we will assess the efficacy of intratracheally instilled ascorbate, NAC, deferoxamine, Infasurf (a surfactant replacement mixture), albuterol and the tip peptide, as well as aerosolized albuterol, in prolonging survival of rats with respiratory failure post C12 exposure. The subject matter of this research is both timely and important: more than 25 million tons of chlorine is manufactured annually in the United States and the majority of this gas is transported by rail and can be used as a chemical weapon.

Department of Comemerce/Sea Grant Support (NOAA)
Nanoparticle Induced Injury to Adult and Developing Lungs
Director: Matalon, Sadis
Project Leader Project 1: Matalon, Sadis

There has been considerable excitement with the use of nanoparticles (i.e. particles less that 100 nm in one dimension) in numerous industrial and biological applications. During the last ten years, nanoparticles have been used extensively in water purification, building of a new generations of superfast computers, and in various biomedical applications (such as development of novel drug delivery systems and highly efficient contrast materials (1)). Presently, little is known about the short and long term toxicity of nanoparticles to biological systems. Pulmonary toxicity is of primary concern since nanoparticles may either be inhaled accidentally or instilled deliberately in the lungs for various medical applications. In addition, the lungs are continuously perfused with about 6 liters of blood per minute (the approximate value of the total cardiac output of a 170 lbs healthy person); thus some of the nanoparticles which have either aggregated forming large complexes or adhered to red cells may be trapped in the pulmonary capillaries. Significant concerns also exist with possible exposure of pregnant mothers as well as newborn children to nanoparticles. Understanding the basic mechanisms by which nanoparticles damage lung tissues as well as identifying the short and long term physiological sequelae to fetal, newborn and adult mammalian lungs will spearhead additional research in identifying specific agents to limit toxicity thus allowing the more widespread use of these agents in industrial and biomedical applications.

The overall purpose of this Program Project Grant (“Nanonoparticle Induced Injury to the Fetal, Newborn and Adult Mammalian Lungs”) is to use state of the art proteomics, biochemical, biophysical, morphological and physiological approaches to precisely document the extent and types of lung injury to animals (fetal, newborn and adult mice; adult rats) exposed to commonly used nanoparticles (cadmium-selenium quantum dots and titanium oxide nanoparticles). The program project consists of two cores and four independent but well integrated and highly interactive projects. The basic premise is that inhaled or injected nanoparticles trapped in the lung air or vascular spaces generate reactive oxygen and reactive nitrogen species which compromise seminal functions of the alveolar epithelium; in addition, reactive species per se, or products generated by tissue injury, activate NFkb and initiate inflammatory cascades which contribute and amplify the injury. The end result is the development of both acute and potentially chronic lung injury which may predispose individuals to a variety of other common lung ailments such as asthma, emphysema and acute lung injury.