Presence, enzymatic activity, and subcellular localization of paraoxonases 1, 2, and 3 in human lung tissues

• Published in: Life sciences (1973) Vol. 311; no. Pt A; p. 121147
• Main Authors: Cavallero, A., Puccini, P., Aprile, V., Lucchi, M., Gervasi, P.G., Longo, V., Gabriele, M.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.12.2022
• Subjects: A549 cell line; aryldialkylphosphatase; cell lines; cytosol; EDTA (chelating agent); enzyme activity; family; fluorides; Human lungs; humans; Lactonase activity; lungs; metabolism; microsomes; mitochondria; Organophosphate activity; organophosphorus compounds; Paraoxonases; phosphates; PONs expression; Western blotting; Paraoxonases; PONs expression; A549 cell line; Organophosphate activity; Lactonase activity; Human lungs
• ISSN: 0024-3205; 1879-0631; 1879-0631
• DOI: 10.1016/j.lfs.2022.121147

The human paraoxonases family (PONs) includes three calcium-dependent esterases: PON1, PON2, and PON3. The presence of PONs mRNA in human lungs is known, however, their enzymatic activity and subcellular localization have not been sufficiently explored. In this work, the presence of PONs in human lung tissues, at both mRNA and protein levels, was confirmed by Real-Time RT-PCR and Western blot analysis. Moreover, the activities of PONs were determined in cytosol and microsomes of 30 subjects and in mitochondria of 8 representative lung tissues using selective and non-selective substrates. Besides, to exclude the possible contribution of other esterases on PON1 organophosphate activity, the effect of bis-p-nitrophenyl phosphate (BNPP) and phenylmethylsulfonyl fluoride (PMSF), esterase inhibitors, and ethylenediaminetetraacetic acid (EDTA), a general paraoxonase inhibitor, was tested. Finally, the presence and activities of PONs in the A549 pulmonary cell line were also evaluated in order to be used as a model for studies on paraoxonases' metabolism. Our results demonstrated high interindividual variability in both PONs mRNA/protein levels and enzymatic activities and pointed out the presence of all PONs in human lungs and their subcellular distribution in the cytosol, microsomes, and mitochondria. These findings add further information to our knowledge of pulmonary metabolism and, given that PON1 can metabolize some drugs used for respiratory diseases, the presence of PON1 activity in the lung tissue should no longer be ignored in the development of treatment plans and the design of new drugs. •PON1, PON2, and PON3 activities estimation in several human lung tissues.•PONs subcellular distribution analysis in lung cytosol, microsomes, and mitochondria.•PONs activity was detected in lung cytosol, microsomes, and mitochondrial fractions.•High inter-individual variability in PONs expression and activities was found.•A549 cell line showed similar PONs activities to those observed in lung tissues.