Animal models and mechanisms of tobacco smoke-induced chronic obstructive pulmonary disease (COPD).

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide, and its global health burden is increasing. COPD is characterized by emphysema, mucus hypersecretion, and persistent lung inflammation, and clinically by chronic airflow obstruction and symptoms of dyspnea, cough, and fatigue in patients. A cluster of pathologies including chronic bronchitis, emphysema, asthma, and cardiovascular disease in the form of hypertension and atherosclerosis variably coexist in COPD patients. Underlying causes for COPD include primarily tobacco use but may also be driven by exposure to air pollutants, biomass burning, and workplace related fumes and chemicals. While no single animal model might mimic all features of human COPD, a wide variety of published models have collectively helped to improve our understanding of disease processes involved in the genesis and persistence of COPD. In this review, the pathogenesis and associated risk factors of COPD are examined in different mammalian models of the disease. Each animal model included in this review is exclusively created by tobacco smoke (TS) exposure. As animal models continue to aid in defining the pathobiological mechanisms of and possible novel therapeutic interventions for COPD, the advantages and disadvantages of each animal model are discussed.

Inhalation of Silver Silicate Nanoparticles Leads to Transient and Differential Microglial Activation in the Rodent Olfactory Bulb.

Engineered silver nanoparticles (AgNPs), including silver silicate nanoparticles (Ag-SiO2 NPs), are used in a wide variety of medical and consumer applications. Inhaled AgNPs have been found to translocate to the olfactory bulb (OB) after inhalation and intranasal instillation. However, the biological effects of Ag-SiO2 NPs and their potential nose-to-brain transport have not been evaluated. The present study assessed whether inhaled Ag-SiO2 NPs can elicit microglial activation in the OB. Adult Sprague-Dawley rats inhaled aerosolized Ag-SiO2 NPs at a concentration of 1 mg/ml for 6 hours. On day 0, 1, 7, and 21 post-exposure, rats were necropsied and OB were harvested. Immunohistochemistry on OB tissues were performed with anti-ionized calcium-binding adapter molecule 1 and heme oxygenase-1 as markers of microglial activation and oxidative stress, respectively. Aerosol characterization indicated Ag-SiO2 NPs were sufficiently aerosolized with moderate agglomeration and high-efficiency deposition in the nasal cavity and olfactory epithelium. Findings suggested that acute inhalation of Ag-SiO2 NPs elicited transient and differential microglial activation in the OB without significant microglial recruitment or oxidative stress. The delayed and differential pattern of microglial activation in the OB implied that inhaled Ag-SiO2 may have translocated to the central nervous system via intra-neuronal pathways.

Engineered Pseudomonas putida for biosynthesis of catechol from lignin-derived model compounds and biomass hydrolysate.

Catechol is an industrially relevant chemical with myriad applications. Its production via chemical route suffers from several drawbacks the major being a non-green and nonselective route. Currently, bio-based products using biocatalyst are gaining attention due to the growing environmental and health hazards concerns over the use of petroleum-derived feedstock. Lignocellulosic biomass serves as a promising feedstock. Lignin valorization is the demand of the current scenario which is complicated task by its complexity, heterogeneity and diversity of lignin structures posing limitations toward lignin valorization via chemical routes. There are several microorganisms that possess the ability to metabolize lignin monomers via their central metabolic pathways and this paves the way to the synthesis of a number of products. Pseudomonas putida KT2440 is one such organism and was chosen for genetic manipulations for catechol biosynthesis using lignin-derived model compounds and biomass hydrolysate stream comprising of various lignin monomers. Catechol production was engineered by diverting various lignin monomers and addressing the identified metabolic bottlenecks particularly vanillic acid accumulation toward catechol biosynthesis. The engineered strain could convert the model lignin monomers as well as monomers in the biomass hydrolysates to catechol and vanillic acid in more than 60% and 90% molar yields, respectively.

Microscopic and Transcriptomic Analyses of Dalbergoid Legume Peanut Reveal a Divergent Evolution Leading to Nod-Factor-Dependent Epidermal Crack-Entry and Terminal Bacteroid Differentiation.

Root nodule symbiosis (RNS) is the pillar behind sustainable agriculture and plays a pivotal role in the environmental nitrogen cycle. Most of the genetic, molecular, and cell-biological knowledge on RNS comes from model legumes that exhibit a root-hair mode of bacterial infection, in contrast to the Dalbergoid legumes exhibiting crack-entry of rhizobia. As a step toward understanding this important group of legumes, we have combined microscopic analysis and temporal transcriptome to obtain a dynamic view of plant gene expression during Arachis hypogaea (peanut) nodule development. We generated comprehensive transcriptome data by mapping the reads to A. hypogaea, and two diploid progenitor genomes. Additionally, we performed BLAST searches to identify nodule-induced yet-to-be annotated peanut genes. Comparison between peanut, Medicago truncatula, Lotus japonicus, and Glycine max showed upregulation of 61 peanut orthologs among 111 tested known RNS-related genes, indicating conservation in mechanisms of nodule development among members of the Papilionoid family. Unlike model legumes, recruitment of class 1 phytoglobin-derived symbiotic hemoglobin (SymH) in peanut indicates diversification of oxygen-scavenging mechanisms in the Papilionoid family. Finally, the absence of cysteine-rich motif-1-containing nodule-specific cysteine-rich peptide (NCR) genes but the recruitment of defensin-like NCRs suggest a diverse molecular mechanism of terminal bacteroid differentiation. In summary, our work describes genetic conservation and diversification in legume-rhizobia symbiosis in the Papilionoid family, as well as among members of the Dalbergoid legumes.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Protocatechuic acid production from lignin-associated phenolics.

Biobased chemicals are gaining popularity and market in attempts to mitigate the deteriorating environmental and sustainability issues. Components of renewable agricultural and forest biomass residues are projected to serve as abundant precursors to synthesis of expanding range of products. Agroindustrial wastes comprises of several phenolic compounds associated with lignin via ether linkages such as ferulic acid, p-coumaric, syringic acid and vanillin. These aromatic chemicals have myriad industrial applications. In this study, p-coumaric acid and ferulic acid were found to be two major components in corn bran derived lignin hydrolysate. Engineered Pseudomonas putida KT2440 was constructed and found to convert p-coumaric acid and vanillic acid to protocatechuic acid in >90% and >50% yields, respectively. Engineering the strain included deletion of the gene encoding protocatechuate 3,4-dioxygenase, and overexpression of vanillate-O-demethylase gene from Acinetobacter sp. ADP1.

Differential lung inflammation and injury with tobacco smoke exposure in Wistar Kyoto and spontaneously hypertensive rats.

OBJECTIVE: Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide and has been associated with periods of intense lung inflammation. The objective of this study was to characterize whether similar rat strains, possessing different genetic predispositions, might play a role in exacerbating the pathophysiology of COPD-like cellular and structural changes with progressive 12-week exposure to tobacco smoke (TS). Normotensive Wistar Kyoto (WKY) and spontaneously hypertensive (SH) rats were compared. MATERIALS AND METHODS: WKY and SH rats were exposed to filtered air or to tobacco smoke at a particulate concentration of 80 mg/m3 for 4, 8, or 12 weeks. Necropsy was performed 24 h after the last exposure to obtain cells by bronchoalveolar lavage for total cell and differential counts. Scoring of lung tissues and immunohistochemical staining for M1 (pro-inflammatory) and M2 (anti-inflammatory) macrophages were performed on paraffin-embedded lung sections. RESULTS AND DISCUSSION: With progressive exposure, TS-exposed SH rats demonstrated significant airspace enlargement, mucin production, and lung inflammation compared to their FA control and TS-matched WKY rats. Moreover, SH rats also demonstrated increased expression of the M1 marker in alveolar macrophages compared to FA control, as well as the M2 marker compared to controls and TS-exposed WKY rats. CONCLUSION: The progressive tobacco smoke exposure contributes to persistent lung injury and inflammation that can be significantly enhanced by rat strain susceptibility in the genesis of COPD.

Biotransformation of corn bran derived ferulic acid to vanillic acid using engineered Pseudomonas putida KT2440.

Ferulic acid is a fraction of the phenolics present in cereals such as rice and corn as a component of the bran. Substantial amounts of waste bran are generated by the grain processing industry and this can be valorized via extraction, purification and conversion of phenolics to value added chemical products. Alkaline alcohol based extracted and purified ferulic acid from corn bran was converted to vanillic acid using engineered Pseudomonas putida KT2440. The strain was engineered by rendering the vanAB gene nonfunctional and obtaining the mutant defective in vanillic acid metabolism. Biotransformation of ferulic acid using resting Pseudomonas putida KT2440 mutant cells resulted in more than 95 ± 1.4% molar yield from standard ferulic acid; while the corn bran derived ferulic acid gave 87 ± 0.38% molar yield. With fermentation time of less than 24 h the mutant becomes a promising candidate for the stable biosynthesis of vanillic acid at industrial scale.

Cardiopulmonary Health Effects of Airborne Particulate Matter: Correlating Animal Toxicology to Human Epidemiology.

The effects of particulate matter (PM) on cardiopulmonary health have been studied extensively over the past three decades. Particulate matter is the primary criteria air pollutant most commonly associated with adverse health effects on the cardiovascular and respiratory systems. The mechanisms by which PM exerts its effects are thought to be due to a variety of factors which may include, but are not limited to, concentration, duration of exposure, and age of exposed persons. Adverse effects of PM are strongly driven by their physicochemical properties, sites of deposition, and interactions with cells of the respiratory and cardiovascular systems. The direct translocation of particles, as well as neural and local inflammatory events, are primary drivers for the observed cardiopulmonary health effects. In this review, toxicological studies in animals, and clinical and epidemiological studies in humans are examined to demonstrate the importance of using all three approaches to better define potential mechanisms driving health outcomes upon exposure to airborne PM of diverse physicochemical compositions.

Neutrophil extracellular traps produced during inflammation awaken dormant cancer cells in mice.

Cancer cells from a primary tumor can disseminate to other tissues, remaining dormant and clinically undetectable for many years. Little is known about the cues that cause these dormant cells to awaken, resume proliferating, and develop into metastases. Studying mouse models, we found that sustained lung inflammation caused by tobacco smoke exposure or nasal instillation of lipopolysaccharide converted disseminated, dormant cancer cells to aggressively growing metastases. Sustained inflammation induced the formation of neutrophil extracellular traps (NETs), and these were required for awakening dormant cancer. Mechanistic analysis revealed that two NET-associated proteases, neutrophil elastase and matrix metalloproteinase 9, sequentially cleaved laminin. The proteolytically remodeled laminin induced proliferation of dormant cancer cells by activating integrin α3ß1 signaling. Antibodies against NET-remodeled laminin prevented awakening of dormant cells. Therapies aimed at preventing dormant cell awakening could potentially prolong the survival of cancer patients.

Insights into metabolism and sodium chloride adaptability of carbaryl degrading halotolerant Pseudomonas sp. strain C7.

Pseudomonas sp. strain C7 isolated from sediment of Thane creek near Mumbai, India, showed the ability to grow on glucose and carbaryl in the presence of 7.5 and 3.5% of NaCl, respectively. It also showed good growth in the absence of NaCl indicating the strain to be halotolerant. Increasing salt concentration impacted the growth on carbaryl; however, the specific activity of various enzymes involved in the metabolism remained unaffected. Among various enzymes, 1-naphthol 2-hydroxylase was found to be sensitive to chloride as compared to carbaryl hydrolase and gentisate 1,2-dioxygenase. The intracellular concentration of Cl- ions remained constant (6-8 mM) for cells grown on carbaryl either in the presence or absence of NaCl. Thus the ability to adapt to the increasing concentration of NaCl is probably by employing chloride efflux pump and/or increase in the concentration of osmolytes as mechanism for halotolerance. The halotolerant nature of the strain will be beneficial to remediate carbaryl from saline agriculture fields, ecosystems and wastewaters.