A Matrix Metalloproteinase Inhibitor, ONO-4817, Suppresses the Development of Aortic Intimal Hyperplasia in Experimental Hyperlipidemic Rabbit

Gene expression profiles in COVID-19-associated tracheal stenosis indicate persistent anti-viral response and dysregulated retinol metabolism

INTRODUCTION

Coronavirus disease 2019 (COVID-19)-associated tracheal stenosis (COATS) may occur as a result of prolonged intubation during COVID-19 infection. We aimed to investigate patterns of gene expression in the tracheal granulation tissue of patients with COATS, leverage gene expression data to identify dysregulated cellular pathways and processes, and discuss potential therapeutic options based on the identified gene expression profiles.

METHODS

Adult patients (age ≥ 18 years) presenting to clinics for management of severe, recalcitrant COATS were included in this study. RNA sequencing and differential gene expression analysis was performed with transcriptomic data for normal tracheal tissue being used as a control. The top ten most highly upregulated and downregulated genes were identified. For each of these pathologically dysregulated genes, we identified key cellular pathways and processes they are involved in using Gene Ontology (GO) and KEGG (Kyoto Encyclopedia of Genes and Genomes) applied via Database for Annotation, Visualization, and Integrated Discovery (DAVID).

RESULTS

Two women, aged 36 years and 37 years, were included. The profile of dysregulated genes indicated a cellular response consistent with viral infection (CXCL11, PI15, CCL8, DEFB103A, IFI6, ACOD1, and DEFB4A) and hyperproliferation/hypergranulation (MMP3, CASP14 and HAS1), while downregulated pathways included retinol metabolism (ALDH1A2, RBP1, RBP4, CRABP1 and CRABP2).

CONCLUSION

Gene expression changes consistent with persistent viral infection and dysregulated retinol metabolism may promote tracheal hypergranulation and hyperproliferation leading to COATS. Given the presence of existing literature highlighting retinoic acid's ability to favorably regulate these genes, improve cell-cell adhesion, and decrease overall disease severity in COVID-19, future studies must evaluate its utility for adjunctive management of COATS in animal models and clinical settings.

Pharmacological Inhibition of MMP3 as a Potential Therapeutic Option for COVID-19 Associated Acute Respiratory Distress Syndrome

The high mortality of coronavirus disease 2019 (COVID-19) patients is due to their progression to cytokine-associated organ injuries, primarily the acute respiratory distress syndrome (ARDS). The uncertainties in the molecular mechanisms leading to the switch from the early virus infection to the advanced stage ARDS is a major gridlock in therapeutic development to reduce mortality. Previous studies in our laboratory have identified matrix metalloprotease-3 (MMP3) as an important mediator of bacterial lipopolysaccharide (LPS)-induced ARDS, particularly in the exudative phase. Our studies have also reported elevated plasma MMP3 activity levels in the ARDS patients and that inhibition of MMP3 can reduce the severity of LPS-induced ARDS in mice. Given these observations, targeting MMP3 could be a potential option to treat COVID-19 patients with ARDS, and measurement of MMP3 activity in the plasma may serve as a biomarker for the early detection of ARDS in COVID-19 patients.

Pneumococcal Infection Aggravates Elastase-Induced Emphysema via Matrix Metalloproteinase 12 Overexpression

BACKGROUND

Acute exacerbation of chronic obstructive pulmonary disease (COPD)--typically caused by bacterial or viral infection--is associated with poor prognosis and emphysema progression through unknown mechanisms. We aimed to elucidate the mechanisms responsible for the poor prognosis and emphysema progression associated with COPD exacerbation.

METHODS

We established a mouse model mimicking acute human COPD exacerbation, wherein mice with elastase-induced emphysema were intranasally infected with Streptococcus pneumoniae.

RESULTS

In mice with elastase-induced emphysema, infection with S. pneumoniae resulted in increased mortality, an increased number of inflammatory cells in bronchoalveolar lavage fluid (BALF), and increased matrix metalloproteinase 12 (MMP-12) production in the lungs, as well as enhanced emphysema progression. The increased MMP-12 production was mostly due to alveolar type II cells, alveolar macrophages, and lymphocytes that aggregated around vessels and bronchioles. Dexamethasone treatment suppressed the mortality rate and number of inflammatory cells in BALF but not emphysema progression, possibly owing to the failure of MMP-12 suppression in the lungs, whereas treatment with the MMP inhibitor ONO-4817 dramatically suppressed both mortality rate and emphysema progression.

CONCLUSIONS

These results suggest that MMP-12 production during COPD exacerbation results in increased mortality and emphysema progression. Our study identifies MMP-12 as a target to prevent further aggravation of COPD.

Montelukast inhibits matrix metalloproteinases expression in atherosclerotic rabbits

BACKGROUND

Matrix metalloproteinases (MMPs) play important roles in the development and destabilization of atherosclerotic plaques. It is known that montelukast inhibits neointimal hyperplasia. However, the underlying mechanisms for the inhibitory effects of montelukast on neointimal formation have been poorly defined.

METHODS

Thirty-six male New Zealand White rabbits were randomized as normal control, placebo (0.9% NaCl, 1.5 ml/kg/day, via intraperitoneal injection), atorvastatin (atorvastatin, 1.5 mg/kg/day, orally) and montelukast groups (montelukast, 1.5 mg/kg/day, via intraperitoneal injection). Atherosclerosis was induced by balloon-injury and high-cholesterol (HC) diet. Serum lipids were measured at 0, 8 and 12 weeks. After 12 weeks, the rabbits were sacrificed and histopathological changes examined. Immunohistochemistry and reverse transcription-polymerase chain reaction were used to measure the expression of MMP-2 and MMP-9 in the plaques.

RESULTS

It was found that montelukast reduced neointimal formation, decreased macrophage accumulation, and increased smooth muscle cells. It also attenuated the expression of MMP-2 and MMP-9 in atherosclerotic plaques, but it had no effect on plasma lipid levels.

CONCLUSION

These data indicate that montelukast inhibits neointimal hyperplasia in association with decreased expression of MMP-2 and MMP-9 independent of plasma lipid levels in atherosclerotic plaques after vascular injury in hyperlipidemic rabbits.

Significance of chymase-dependent matrix metalloproteinase-9 activation on indomethacin-induced small intestinal damages in rats

The side effects of nonsteroidal anti-inflammatory drugs (NSAIDs) include gastrointestinal damage not only in the stomach but also in the small intestine. Chymase converts promatrix metalloproteinase-9 to matrix metalloproteinase (MMP)-9, which plays an important role in NSAID-induced gastric damage, but it has been unclear whether chymase-dependent MMP-9 activation is involved in the NSAID-induced small intestinal damage. To clarify the involvement of chymase-dependent MMP-9 activation on NSAID-induced small intestinal damage, the effect of a chymase inhibitor, 2-[4-(5-fluoro-3-methylbenzo[b]thiophen-2-yl)sulfonamido-3-methanesulfonylphenyl] thiazole-4-carboxylic acid (TY-51469), on indomethacin-induced small intestinal damage in rats was evaluated. Until 6 h after oral administration of indomethacin in rats, intestinal MMP-9 activity was unchanged compared with normal rats, but significant increases in MMP-9 activity were observed 12 and 24 h after indomethacin administration. Significant increases in the small intestinal damage score were also observed 12 and 24 h after indomethacin administration. In the extract from the small intestine 24 h after indomethacin administration, the MMP-9 activation was significantly attenuated by TY-51469. Intraperitoneal injection of TY-51469 (10 mg/kg) 3 h before indomethacin administration significantly attenuated the MMP-9 activity in the small intestine compared with placebo treatment. Myeloperoxidase activity, which indicates accumulation of neutrophils, was significantly increased in the small intestine in the placebo-treated rats, but its activity was significantly attenuated by TY-51469 treatment. The area of small intestinal damage was also significantly ameliorated by TY-51469 treatment. These findings suggest that chymase-dependent MMP-9 activation has a significant role in indomethacin-induced small intestinal damage in rats.