PMID- 24083319 OWN - NLM STAT- MEDLINE DCOM- 20140211 LR - 20220309 IS - 1520-4995 (Electronic) IS - 0006-2960 (Print) IS - 0006-2960 (Linking) VI - 52 IP - 43 DP - 2013 Oct 29 TI - Identification of palmitoyl protein thioesterase 1 in human THP1 monocytes and macrophages and characterization of unique biochemical activities for this enzyme. PG - 7559-74 LID - 10.1021/bi401138s [doi] AB - The profiles of serine hydrolases in human and mouse macrophages are similar yet different. For instance, human macrophages express high levels of carboxylesterase 1 (CES1), whereas mouse macrophages have minimal amounts of the orthologous murine CES1. On the other hand, macrophages from both species exhibit limited expression of the canonical 2-arachidonoylglycerol (2-AG) hydrolytic enzyme, MAGL. Our previous study showed CES1 was partly responsible for the hydrolysis of 2-AG (50%) and prostaglandin glyceryl esters (PG-Gs) (80-95%) in human THP1 monocytes and macrophages. However, MAGL and other endocannabinoid hydrolases, FAAH, ABHD6, and ABHD12, did not have a role because of limited expression or no expression. Thus, another enzyme was hypothesized to be responsible for the remaining 2-AG hydrolysis activity following chemical inhibition and immunodepletion of CES1 (previous study) or CES1 gene knockdown (this study). Here we identified two candidate serine hydrolases in THP1 cell lysates by activity-based protein profiling (ABPP)-MUDPIT and Western blotting: cathepsin G and palmitoyl protein thioesterase 1 (PPT1). Both proteins exhibited electrophoretic properties similar to those of a serine hydrolase in THP1 cells detected by gel-based ABPP at 31-32 kDa; however, only PPT1 exhibited lipolytic activity and hydrolyzed 2-AG in vitro. Interestingly, PPT1 was strongly expressed in THP1 cells but was significantly less reactive than cathepsin G toward the activity-based probe, fluorophosphonate-biotin. KIAA1363, another serine hydrolase, was also identified in THP1 cells but did not have significant lipolytic activity. On the basis of chemoproteomic profiling, immunodepletion studies, and chemical inhibitor profiles, we estimated that PPT1 contributed 32-40% of 2-AG hydrolysis activity in the THP1 cell line. In addition, pure recombinant PPT1 catalyzed the hydrolysis of 2-AG, PGE2-G, and PGF2alpha-G, although the catalytic efficiency of hydrolysis of 2-AG by PPT1 was ~10-fold lower than that of CES1. PPT1 was also insensitive to several chemical inhibitors that potently inhibit CES1, such as organophosphate poisons and JZL184. This is the first report to document the expression of PPT1 in a human monocyte and macrophage cell line and to show PPT1 can hydrolyze the natural substrates 2-AG and PG-Gs. These findings suggest that PPT1 may participate in endocannabinoid metabolism within specific cellular contexts and highlights the functional redundancy often exhibited by enzymes involved in lipid metabolism. FAU - Wang, Ran AU - Wang R AD - Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University , University, Mississippi 39762, United States. FAU - Borazjani, Abdolsamad AU - Borazjani A FAU - Matthews, Anberitha T AU - Matthews AT FAU - Mangum, Lee C AU - Mangum LC FAU - Edelmann, Mariola J AU - Edelmann MJ FAU - Ross, Matthew K AU - Ross MK LA - eng GR - P20 GM103476/GM/NIGMS NIH HHS/United States GR - R15 ES015348/ES/NIEHS NIH HHS/United States GR - 1R15ES015348-02/ES/NIEHS NIH HHS/United States PT - Journal Article PT - Research Support, N.I.H., Extramural PT - Research Support, Non-U.S. Gov't DEP - 20131018 PL - United States TA - Biochemistry JT - Biochemistry JID - 0370623 RN - 0 (Arachidonic Acids) RN - 0 (Endocannabinoids) RN - 0 (Enzyme Inhibitors) RN - 0 (Glycerides) RN - 0 (Membrane Proteins) RN - 0 (RNA, Small Interfering) RN - 0 (Recombinant Proteins) RN - 8D239QDW64 (glyceryl 2-arachidonate) RN - EC 3.1.1.- (Carboxylic Ester Hydrolases) RN - EC 3.1.1.1 (CES1 protein, human) RN - EC 3.1.2.- (Thiolester Hydrolases) RN - EC 3.1.2.22 (PPT1 protein, human) RN - EC 3.1.2.22 (palmitoyl-protein thioesterase) SB - IM MH - Animals MH - Arachidonic Acids/metabolism MH - CHO Cells MH - Carboxylic Ester Hydrolases/antagonists & inhibitors/genetics/metabolism MH - Cell Line MH - Cells, Cultured MH - Cricetinae MH - Cricetulus MH - Endocannabinoids/metabolism MH - Enzyme Inhibitors/pharmacology MH - Female MH - Glycerides/metabolism MH - Hep G2 Cells MH - Humans MH - Hydrolysis MH - Macrophages/cytology/*enzymology/immunology/metabolism MH - Membrane Proteins/antagonists & inhibitors/genetics/*metabolism MH - Mice MH - Monocytes/cytology/*enzymology/immunology/metabolism MH - RNA Interference MH - RNA, Small Interfering MH - Recombinant Proteins/chemistry/metabolism MH - Substrate Specificity MH - Thiolester Hydrolases/antagonists & inhibitors/genetics/*metabolism PMC - PMC4102699 MID - NIHMS598140 COIS- Notes: The authors declare no competing financial interest. EDAT- 2013/10/03 06:00 MHDA- 2014/02/12 06:00 PMCR- 2014/07/18 CRDT- 2013/10/03 06:00 PHST- 2013/10/03 06:00 [entrez] PHST- 2013/10/03 06:00 [pubmed] PHST- 2014/02/12 06:00 [medline] PHST- 2014/07/18 00:00 [pmc-release] AID - 10.1021/bi401138s [doi] PST - ppublish SO - Biochemistry. 2013 Oct 29;52(43):7559-74. doi: 10.1021/bi401138s. Epub 2013 Oct 18.