Project Title

FATTY ACID AMIDE HYDROLASE IN NAE METABOLIC PATHWAY IN PHYSCOMITRELLA PATENS

Authors' Affiliations

Md I Haq and Aruna Kilaru, Department of Biological Sciences, College of Arts and Sciences, East Tennessee State University, Johnson City, TN.

Location

RIPSHIN MTN. ROOM 130

Start Date

4-4-2018 1:20 PM

End Date

4-4-2018 1:35 PM

Name of Project's Faculty Sponsor

Aruna Kilaru

Faculty Sponsor's Department

Department of Biological Sciences

Type

Oral Presentation

Classification of First Author

Graduate Student-Doctoral

Project's Category

Natural Sciences

Abstract Text

In plants, saturated and unsaturated N-acylethanolamines (NAEs) with acyl chains 12C to 20C are reported for their differential levels in various tissues and species. While NAEs were shown to play a vital role in mammalian neurological and physiological functions, their metabolism and functional implications in plants however, remain incomplete. Fatty acid amide hydrolase (FAAH) is one of the metabolic enzymes that breaks the amide bond in NAEs to release free fatty acid and ethanolamine. FAAH orthologs, putative PpFAAHs (Physcomitrella patens FAAH) were identified based on the sequence blast of ratFAAH, and named as PpFAAH1 to PpFAAH10. Based on the highest mRNA expression of the PpFAAH homologs upon NAE treatment, PpFAAH1 was selected for further in vitro characterization, which shares 31% sequence identity with ratFAAH. PpFAAH1 was heterologously expressed in E. coli and purified for characterization. Highest amidohydrolysis activity of PpFAAH1 was observed in vitro at pH 8.0 and temperature 37°C. Methoxy arachidonyl fluorophosphonate (MAFP), an inhibitor showed highest inhibition with 10mM concentration, however, one of the principal classes of FAAH inhibitor O-aryl carbamates (URB597) exhibited only 22% inhibition with the same concentration. Both in vivo and in vitro studies showed that unsaturated NAE substrate (NAE 20:4) is hydrolyzed faster than the saturated NAE (NAE16:0); more than 50- and 10-fold higher in vitro and in vivo assays, respectively. Amidohydrolase activity in vivo was mostly associated with microsomes compared with cytoplasmic fractions. Additionally, microsomal fraction of mature gametophytes showed higher amidohydrolase activity than of the protonemal or early gametophyte stages; however, PpFAAH expression was not significantly different between the developmental stages. Further functional characterization of NAE metabolic pathway is ongoing by generation of PpFAAH knock out (KO) and overexpressor (OE) to understand the biological implications of FAAH in growth and development of early land plants.

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Apr 4th, 1:20 PM Apr 4th, 1:35 PM

FATTY ACID AMIDE HYDROLASE IN NAE METABOLIC PATHWAY IN PHYSCOMITRELLA PATENS

RIPSHIN MTN. ROOM 130

In plants, saturated and unsaturated N-acylethanolamines (NAEs) with acyl chains 12C to 20C are reported for their differential levels in various tissues and species. While NAEs were shown to play a vital role in mammalian neurological and physiological functions, their metabolism and functional implications in plants however, remain incomplete. Fatty acid amide hydrolase (FAAH) is one of the metabolic enzymes that breaks the amide bond in NAEs to release free fatty acid and ethanolamine. FAAH orthologs, putative PpFAAHs (Physcomitrella patens FAAH) were identified based on the sequence blast of ratFAAH, and named as PpFAAH1 to PpFAAH10. Based on the highest mRNA expression of the PpFAAH homologs upon NAE treatment, PpFAAH1 was selected for further in vitro characterization, which shares 31% sequence identity with ratFAAH. PpFAAH1 was heterologously expressed in E. coli and purified for characterization. Highest amidohydrolysis activity of PpFAAH1 was observed in vitro at pH 8.0 and temperature 37°C. Methoxy arachidonyl fluorophosphonate (MAFP), an inhibitor showed highest inhibition with 10mM concentration, however, one of the principal classes of FAAH inhibitor O-aryl carbamates (URB597) exhibited only 22% inhibition with the same concentration. Both in vivo and in vitro studies showed that unsaturated NAE substrate (NAE 20:4) is hydrolyzed faster than the saturated NAE (NAE16:0); more than 50- and 10-fold higher in vitro and in vivo assays, respectively. Amidohydrolase activity in vivo was mostly associated with microsomes compared with cytoplasmic fractions. Additionally, microsomal fraction of mature gametophytes showed higher amidohydrolase activity than of the protonemal or early gametophyte stages; however, PpFAAH expression was not significantly different between the developmental stages. Further functional characterization of NAE metabolic pathway is ongoing by generation of PpFAAH knock out (KO) and overexpressor (OE) to understand the biological implications of FAAH in growth and development of early land plants.