A novel FADS2 isoform identified in human milk fat globule suppresses FADS2 mediated Δ6-desaturation of omega-3 fatty acids

Kumar S.D. Kothapalli, Hui Gyu Park, Xiaoxian Guo, Xuepeng Sun, James Zou, Stephanie S. Hyon, Xia Qin, Peter Lawrence, Rinat R. Ran-Ressler, Ji Yao Zhang, Zhenglong Gu, J. Thomas Brenna

Research output: Contribution to journalArticle

Abstract

Introduction: The only known non-pharmacological means to alter long chain polyunsaturated fatty acid (LCPUFA) abundance in mammalian tissue is by altering substrate fatty acid ratios. Alternative mRNA splicing is increasingly recognized as a modulator of protein structure and function. Here we report identification of a novel alternative transcript (AT) of fatty acid desaturase 2 (FADS2) that inhibits production of omega-3 but not omega-6 LCPUFA, discovered during study of ATs in human milk fat globules (MFG). Methods: Human breastmilk collected from a single donor was used to isolate MFG. An mRNA-sequencing library was constructed from the total RNA isolated from the MFG. The constructed library was sequenced using an Illumina HiSeq instrument operating in high output mode. Expression levels of evolutionary conserved FADSAT were measured using cDNA from MFG by semi-quantitative RT-PCR assay. Results: RNA sequencing revealed >15,000 transcripts, including moderate expression of the FADS2 classical transcript (CS). A novel FADS2 alternative transcript (FADS2AT2) with 386 amino acids was discovered. When FADS2AT2 was transiently transfected into MCF7 cells stably expressing FADS2, delta-6 desaturation (D6D) of alpha-linolenic acid 18:3n−3 → 18:4n−3 was suppressed as were downstream products 20:4n−3 and 20:5n−3. In contrast, no significant effect on D6D of linoleic acid 18:2n−6 → 18:3n−6 or downstream products was observed. FADS2, FADS2AT1 and 5 out of 8 known FADS3AT were expressed in MFG. FADS1, FADS3AT3, and FADS3AT5 are undetectable. Conclusion: The novel, noncatalytic FADS2AT2 regulates FADS2CS-mediated Δ6-desaturation of omega-3 but not omega-6 PUFA biosynthesis. This spliced isoform mediated interaction is the first molecular mechanism by which desaturation of one PUFA family but not the other is modulated.

LanguageEnglish (US)
JournalProstaglandins Leukotrienes and Essential Fatty Acids
DOIs
StateAccepted/In press - Jan 1 2018

Fingerprint

Fatty Acid Desaturases
Omega-3 Fatty Acids
Human Milk
Protein Isoforms
Unsaturated Fatty Acids
Linoleoyl-CoA Desaturase
RNA
RNA Sequence Analysis
Messenger RNA
alpha-Linolenic Acid
Biosynthesis
MCF-7 Cells
Alternative Splicing
Linoleic Acid
Modulators
Libraries
Assays
Fatty Acids
Complementary DNA
milk fat globule

Keywords

  • Alternative transcript
  • Desaturase
  • Elongase
  • Milk fat globule
  • Polyunsaturated fatty acid

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology

Cite this

A novel FADS2 isoform identified in human milk fat globule suppresses FADS2 mediated Δ6-desaturation of omega-3 fatty acids. / Kothapalli, Kumar S.D.; Park, Hui Gyu; Guo, Xiaoxian; Sun, Xuepeng; Zou, James; Hyon, Stephanie S.; Qin, Xia; Lawrence, Peter; Ran-Ressler, Rinat R.; Zhang, Ji Yao; Gu, Zhenglong; Brenna, J. Thomas.

In: Prostaglandins Leukotrienes and Essential Fatty Acids, 01.01.2018.

Research output: Contribution to journalArticle

Kothapalli, Kumar S.D. ; Park, Hui Gyu ; Guo, Xiaoxian ; Sun, Xuepeng ; Zou, James ; Hyon, Stephanie S. ; Qin, Xia ; Lawrence, Peter ; Ran-Ressler, Rinat R. ; Zhang, Ji Yao ; Gu, Zhenglong ; Brenna, J. Thomas. / A novel FADS2 isoform identified in human milk fat globule suppresses FADS2 mediated Δ6-desaturation of omega-3 fatty acids. In: Prostaglandins Leukotrienes and Essential Fatty Acids. 2018.
@article{89a308b76fcf4411b24562444d01d77d,
title = "A novel FADS2 isoform identified in human milk fat globule suppresses FADS2 mediated Δ6-desaturation of omega-3 fatty acids",
abstract = "Introduction: The only known non-pharmacological means to alter long chain polyunsaturated fatty acid (LCPUFA) abundance in mammalian tissue is by altering substrate fatty acid ratios. Alternative mRNA splicing is increasingly recognized as a modulator of protein structure and function. Here we report identification of a novel alternative transcript (AT) of fatty acid desaturase 2 (FADS2) that inhibits production of omega-3 but not omega-6 LCPUFA, discovered during study of ATs in human milk fat globules (MFG). Methods: Human breastmilk collected from a single donor was used to isolate MFG. An mRNA-sequencing library was constructed from the total RNA isolated from the MFG. The constructed library was sequenced using an Illumina HiSeq instrument operating in high output mode. Expression levels of evolutionary conserved FADSAT were measured using cDNA from MFG by semi-quantitative RT-PCR assay. Results: RNA sequencing revealed >15,000 transcripts, including moderate expression of the FADS2 classical transcript (CS). A novel FADS2 alternative transcript (FADS2AT2) with 386 amino acids was discovered. When FADS2AT2 was transiently transfected into MCF7 cells stably expressing FADS2, delta-6 desaturation (D6D) of alpha-linolenic acid 18:3n−3 → 18:4n−3 was suppressed as were downstream products 20:4n−3 and 20:5n−3. In contrast, no significant effect on D6D of linoleic acid 18:2n−6 → 18:3n−6 or downstream products was observed. FADS2, FADS2AT1 and 5 out of 8 known FADS3AT were expressed in MFG. FADS1, FADS3AT3, and FADS3AT5 are undetectable. Conclusion: The novel, noncatalytic FADS2AT2 regulates FADS2CS-mediated Δ6-desaturation of omega-3 but not omega-6 PUFA biosynthesis. This spliced isoform mediated interaction is the first molecular mechanism by which desaturation of one PUFA family but not the other is modulated.",
keywords = "Alternative transcript, Desaturase, Elongase, Milk fat globule, Polyunsaturated fatty acid",
author = "Kothapalli, {Kumar S.D.} and Park, {Hui Gyu} and Xiaoxian Guo and Xuepeng Sun and James Zou and Hyon, {Stephanie S.} and Xia Qin and Peter Lawrence and Ran-Ressler, {Rinat R.} and Zhang, {Ji Yao} and Zhenglong Gu and Brenna, {J. Thomas}",
year = "2018",
month = "1",
day = "1",
doi = "10.1016/j.plefa.2018.06.004",
language = "English (US)",
journal = "Prostaglandins Leukotrienes and Essential Fatty Acids",
issn = "0952-3278",
publisher = "Churchill Livingstone",

}

TY - JOUR

T1 - A novel FADS2 isoform identified in human milk fat globule suppresses FADS2 mediated Δ6-desaturation of omega-3 fatty acids

AU - Kothapalli, Kumar S.D.

AU - Park, Hui Gyu

AU - Guo, Xiaoxian

AU - Sun, Xuepeng

AU - Zou, James

AU - Hyon, Stephanie S.

AU - Qin, Xia

AU - Lawrence, Peter

AU - Ran-Ressler, Rinat R.

AU - Zhang, Ji Yao

AU - Gu, Zhenglong

AU - Brenna, J. Thomas

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Introduction: The only known non-pharmacological means to alter long chain polyunsaturated fatty acid (LCPUFA) abundance in mammalian tissue is by altering substrate fatty acid ratios. Alternative mRNA splicing is increasingly recognized as a modulator of protein structure and function. Here we report identification of a novel alternative transcript (AT) of fatty acid desaturase 2 (FADS2) that inhibits production of omega-3 but not omega-6 LCPUFA, discovered during study of ATs in human milk fat globules (MFG). Methods: Human breastmilk collected from a single donor was used to isolate MFG. An mRNA-sequencing library was constructed from the total RNA isolated from the MFG. The constructed library was sequenced using an Illumina HiSeq instrument operating in high output mode. Expression levels of evolutionary conserved FADSAT were measured using cDNA from MFG by semi-quantitative RT-PCR assay. Results: RNA sequencing revealed >15,000 transcripts, including moderate expression of the FADS2 classical transcript (CS). A novel FADS2 alternative transcript (FADS2AT2) with 386 amino acids was discovered. When FADS2AT2 was transiently transfected into MCF7 cells stably expressing FADS2, delta-6 desaturation (D6D) of alpha-linolenic acid 18:3n−3 → 18:4n−3 was suppressed as were downstream products 20:4n−3 and 20:5n−3. In contrast, no significant effect on D6D of linoleic acid 18:2n−6 → 18:3n−6 or downstream products was observed. FADS2, FADS2AT1 and 5 out of 8 known FADS3AT were expressed in MFG. FADS1, FADS3AT3, and FADS3AT5 are undetectable. Conclusion: The novel, noncatalytic FADS2AT2 regulates FADS2CS-mediated Δ6-desaturation of omega-3 but not omega-6 PUFA biosynthesis. This spliced isoform mediated interaction is the first molecular mechanism by which desaturation of one PUFA family but not the other is modulated.

AB - Introduction: The only known non-pharmacological means to alter long chain polyunsaturated fatty acid (LCPUFA) abundance in mammalian tissue is by altering substrate fatty acid ratios. Alternative mRNA splicing is increasingly recognized as a modulator of protein structure and function. Here we report identification of a novel alternative transcript (AT) of fatty acid desaturase 2 (FADS2) that inhibits production of omega-3 but not omega-6 LCPUFA, discovered during study of ATs in human milk fat globules (MFG). Methods: Human breastmilk collected from a single donor was used to isolate MFG. An mRNA-sequencing library was constructed from the total RNA isolated from the MFG. The constructed library was sequenced using an Illumina HiSeq instrument operating in high output mode. Expression levels of evolutionary conserved FADSAT were measured using cDNA from MFG by semi-quantitative RT-PCR assay. Results: RNA sequencing revealed >15,000 transcripts, including moderate expression of the FADS2 classical transcript (CS). A novel FADS2 alternative transcript (FADS2AT2) with 386 amino acids was discovered. When FADS2AT2 was transiently transfected into MCF7 cells stably expressing FADS2, delta-6 desaturation (D6D) of alpha-linolenic acid 18:3n−3 → 18:4n−3 was suppressed as were downstream products 20:4n−3 and 20:5n−3. In contrast, no significant effect on D6D of linoleic acid 18:2n−6 → 18:3n−6 or downstream products was observed. FADS2, FADS2AT1 and 5 out of 8 known FADS3AT were expressed in MFG. FADS1, FADS3AT3, and FADS3AT5 are undetectable. Conclusion: The novel, noncatalytic FADS2AT2 regulates FADS2CS-mediated Δ6-desaturation of omega-3 but not omega-6 PUFA biosynthesis. This spliced isoform mediated interaction is the first molecular mechanism by which desaturation of one PUFA family but not the other is modulated.

KW - Alternative transcript

KW - Desaturase

KW - Elongase

KW - Milk fat globule

KW - Polyunsaturated fatty acid

UR - http://www.scopus.com/inward/record.url?scp=85049321766&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85049321766&partnerID=8YFLogxK

U2 - 10.1016/j.plefa.2018.06.004

DO - 10.1016/j.plefa.2018.06.004

M3 - Article

JO - Prostaglandins Leukotrienes and Essential Fatty Acids

T2 - Prostaglandins Leukotrienes and Essential Fatty Acids

JF - Prostaglandins Leukotrienes and Essential Fatty Acids

SN - 0952-3278

ER -