Regulacija i značaj lizofosfolipaze PNPLA7 u staničnom modelu metabolički aktivnoga tkiva

doctoral thesis

• Title (english): Regulation and significance of lysophospholipase PNPLA7 in a cellular model of metabolically active tissue
• Author: Ana-Marija Lulić
• Mentor: Maja Katalinić (mentor)
• Committee member: Morana Dulić (predsjednik povjerenstva)
• Committee member: Branimir Bertoša (član povjerenstva)
• Committee member: Marija Ljubojević (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2024-12-11, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

Glavni cilj ove doktorske disertacije bio je istražiti važnost lizofosfolipaze PNPLA7 u staničnom modelu metabolički aktivnih tkiva mišića i jetre te procijeniti ovaj enzim kao metu toksičnih organofosfornih (OP) spojeva s obzirom da značaj i uloga ovog enzima nisu još dovoljno poznati. Dobiveni rezultati pokazuju da utišavanje PNPLA7 smanjuje razinu ionske pumpe NKAα1 te mete u signalnim putevima mTOR i AMPK što upućuje na važnost proteina PNPLA7 u osnovnoj fiziološkoj funkciji stanica. Zatim, pokazano je da povišenje koncentracije glukoze i inzulina rezultira smanjenjem razine PNPLA7 što sugerira da je reguliran ovisno o energetskom statusu stanice i da ima potencijalnu ulogu u metabolizmu energije. Također, izrađen je protokol za prekomjernu ekspresiju proteina u bakteriji Escherichia coli s ciljem kinetičke karakterizacije interakcija PNPLA7 sa supstratima i inhibitorima. Mjerenjem enzimske aktivnosti PNPLA7 u lizatima stanica, pokazano je da su eksprimirane forme patatinska domena i AB-patatinska domena katalitički aktivne prema supstratu p-nitrofenil valeratu i da su inhibirane odabranim OP spojevima. Zaključno, dobiveni rezultati upućuju na važnost PNPLA7 i važnost daljnjih istraživanja ovog enzima u razvoju lijekova za mogući tretman otrovanja OP-ima, ali i za liječenje drugih stanja i bolesti povezanih uz metabolizam lipida.

Abstract (english)

The main goal of this doctoral dissertation was to examine the importance of lysophospholipase PNPLA7 in a cellular model of metabolically active muscle and liver tissue and to evaluate this enzyme as a target of toxic organophosphorus (OP) compounds, given that the significance and role of this enzyme are not yet sufficiently known. The obtained results show that the PNPLA7 silencing reduces the level of the ion pump NKAα1 and targets in the mTOR and AMPK signalling pathways, which points to the importance of PNPLA7 in the basic physiological function of cells. Furthermore, it was shown that an increase in glucose and insulin concentration results in a decrease of PNPLA7 levels, suggesting that it is regulated depending on the energy status of the cell and that it has a potential role in energy metabolism. Moreover, protocol for PNPLA7 overexpression in Escherichia coli was proposed for further kinetic studies of its interactions with substrates and inhibitors. By measuring PNPLA7 enzyme activity in cell lysates with p-nitrophenyl valerate, it was shown that the expressed forms of patatin domain and AB-patatin domain are catalytically active and are inhibited by OP compounds. In summary, the obtained results indicate the significance of PNPLA7 and the importance of further research on this enzyme in the development of drugs for the treatment of OP poisoning or in the treatment of other conditions and diseases related to lipid metabolism.

• Keywords: enzimi; metabolizam; PNPLA7; lizofosfolipaza
• Keywords (english): enzyme; metabolism; PNPLA7; lysophospholipase
• Language: croatian
• URN:NBN: urn:nbn:hr:217:052270
• Promotion: 2025
• Project: Number: UIP-2017-05-7260; Title: Molekularni mehanizmi toksičnosti protuotrova i potencijalnih lijekova; Title: Molecular mechanisms underlying the toxicity of antidotes and potential drugs; Acronym: CellToxTargets; Leader: Maja Katalinić; Jurisdiction: Croatia; Funder: Hrvatska zaklada za znanost; Funding stream: Installation Research Projects
• Study programme: Title: Doctoral study; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica u području prirodnih znanosti (doktor/doktorica u području prirodnih znanosti)
• Type of resource: Text
• Extent: 115 , XXXII str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access
• Created on: 2025-02-27 14:45:18