Antioxidant Glutathione Analogues UPF1 and UPF17 Modulate the Expression of Enzymes Involved in the Pathophysiology of Chronic Obstructive Pulmonary Disease

Increased oxidative stress (OS) and systemic inflammation are key players in the pathophysiology of chronic obstructive pulmonary disease (COPD). We aimed to clarify the effects of synthetic glutathione (GSH) analogue peptides UPF1 and UPF17 on the mRNA levels of enzymes involved in systemic inflammation and GSH metabolism in peripheral blood mononuclear cells (PBMCs) from patients with acute exacerbation of COPD (AE-COPD) and stable COPD along with non-obstructive smokers and non-smokers. UPF1 and UPF17 increased the expression of enzymes involved in the formation of the antioxidant capacity: superoxide dismutase 1 (SOD1) and the catalytic subunit of glutamyl-cysteine ligase (GCLC) in patients with AE-COPD and stable COPD, but also in non-obstructive smokers and non-smokers. Similarly, both UPF1 and UPF17 increased the expression of inflammatory enzymes poly(ADP-ribose) polymerase-1 (PARP-1), dipeptidyl peptidase 4 (DPP4), and cyclooxygenase-2 (COX-2). Both UPF analogues acted in a gender-dependent manner by increasing the expression of certain anti-inflammatory (histone deacetylase 2 (HDAC2)) and GSH metabolism pathway (SOD1 and GSH reductase (GSR))-related enzymes in females and decreasing them in males. UPF1 and UPF17 are able to increase the expression of the enzymes involved in GSH metabolism and could serve as a lead for designing potential COPD therapies against excessive OS.

Increased DNA damage in progression of COPD: a response by poly(ADP-ribose) polymerase-1

Chronic oxidative stress (OS), a major mechanism of chronic obstructive pulmonary disease (COPD), may cause significant damage to DNA. Poly(ADP-ribose) polymerase (PARP)-1 is rapidly activated by OS-induced DNA lesions. However, the degree of DNA damage along with the evolution of COPD is unclear. In peripheral blood mononuclear cells of non-smoking individuals, non-obstructive smokers, patients with COPD of all stages and those with COPD exacerbation, we evaluated DNA damage, PARP activity and PARP-1 mRNA expression using Comet Assay IV, biotinylated-NAD incorporation assay and qRT-PCR, respectively and subjected results to ordinal logistic regression modelling. Adjusted for demographics, smoking-related parameters and lung function, novel comet parameters, tail length/cell length ratio and tail migration/cell length ratio, showed the greatest increase along the study groups corresponding to the evolution of COPD [odds ratio (OR) 7.88, 95% CI 4.26–14.57; p<0.001 and OR 3.91, 95% CI 2.69–5.66; p<0.001, respectively]. Analogously, PARP activity increased significantly over the groups (OR = 1.01; 95%; p<0.001). An antioxidant tetrapeptide UPF17 significantly reduced the PARP-1 mRNA expression in COPD, compared to that in non-obstructive individuals (p = 0.040). Tail length/cell length and tail migration/cell length ratios provide novel progression-sensitive tools for assessment of DNA damage. However, it remains to be elucidated whether inhibition of an elevated PARP-1 activity has a safe enough potential to break the vicious cycle of the development and progression of COPD.