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l-Theanine promotes cultured human Sertoli cells proliferation and modulates glucose metabolism

  • Tânia R. Dias
  • Raquel L. Bernardino
  • Marco G. Alves
  • Joaquina Silva
  • Alberto Barros
  • Mário Sousa
  • Susana Casal
  • Branca M. SilvaEmail author
  • Pedro F. OliveiraEmail author
Short Communication
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Abstract

Purpose

l-Theanine is the major free amino acid present in tea (Camellia sinensis L.). The effects of several tea constituents on male reproduction have been investigated, but l-theanine has been overlooked. Sertoli cells (SCs) are essential for the physical and nutritional support of germ cells. In this study, we aimed to investigate the ability of l-theanine to modulate important mechanisms of human SCs (hSCs) metabolism, mitochondrial function and oxidative profile, which are essential to prevent or counteract spermatogenesis disruption in several health conditions.

Methods

We evaluated the effect of a dose of l-theanine attained by tea intake (5 μM) or a pharmacological dose (50 μM) on the metabolism (proton nuclear magnetic resonance and Western blot), mitochondrial functionality (protein expression of mitochondrial complexes and JC1 ratio) and oxidative profile (carbonyl levels, nitration and lipid peroxidation) of cultured hSCs.

Results

Exposure of hSCs to 50 µM of l-theanine increased cell proliferation and glucose consumption. In response to this metabolic adaptation, there was an increase in mitochondrial membrane potential, which may compromise the prooxidant–antioxidant balance. Still, no alterations were observed regarding the oxidative damages.

Conclusions

A pharmacological dose of l-theanine (50 µM) prompts an increase in hSCs proliferation and a higher glucose metabolization to sustain the pool of Krebs cycle intermediates, which are crucial for cellular bioenergetics and biosynthesis. This study suggests an interplay between glycolysis and glutaminolysis in the regulation of hSCs metabolism.

Keywords

Cell metabolism Glutamate l-Theanine Mitochondria Antioxidant Sertoli cell 

Abbreviations

4-HNE

4-Hydroxynonenal

AP

Alkaline phosphatase

BBB

Blood–brain barrier

BTB

Blood–testis barrier

DNP

2,4-Dinitrophenyl

EGCG

Epigallocatechin gallate

FBS

Fetal bovine serum

hSCs

Human Sertoli cells

ITS

Insulin–transferrin–sodium selenite

LDH

Lactate dehydrogenase

MCT4

Monocarboxylate transporter 4

NMR

Nuclear magnetic resonance

PBS

Phosphate-buffered saline

PVDF

Polyvinylidene difluoride

ROS

Reactive oxygen species

SCs

Sertoli cells

SEM

Standard error of the mean

SRB

Sulforhodamine B

Notes

Acknowledgements

This work was supported by “Fundação para a Ciência e a Tecnologia”—FCT to Tânia R. Dias (SFRH/BD/109284/2015); Raquel L. Bernardino (SFRH/BD/103105/2014); Marco G. Alves (IFCT2015); Pedro F. Oliveira (IFCT2015); CICS (UID/Multi/00709/2013), UMIB (PEst-OE/SAU/UI0215/2014) and REQUIMTE (UID/QUI/50006/2013). The work was co-funded by FEDER through the COMPETE/QREN, FSE/POPH (PTDC/BIM-MET/4712/2014 and PTDC/BBB-BQB/1368/2014), and POCI—COMPETE 2020 (POCI-01-0145-FEDER-007491) funds. The funding sources had no involvement in the study design; collection, analysis and interpretation of data; writing of the report; or in the decision to submit the article for publication.

Author contributions

TRD performed most of the experiments, analyzed the results and wrote the first draft of the manuscript. RLB helped in the cell cultures and data interpretation. MGA was responsible for the metabolic analysis and helped in data interpretation and discussion. JS and AB collected the testicular biopsies from the patients and obtained a written consent from each of them. MS, SC, BMS and PFO designed the study, helped with statistical analysis and revised the manuscript. The manuscript was written through the contributions of all authors. All authors have given approval to the final version of the manuscript.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Universidade da Beira InteriorCovilhãPortugal
  2. 2.Department of Microscopy, Laboratory of Cell Biology and Unit for Multidisciplinary Research in Biomedicine Institute of Biomedical Sciences Abel Salazar (ICBAS), University of PortoPortoPortugal
  3. 3.LAQV/REQUIMTE, Laboratory of Bromatology and Hydrology, Faculty of PharmacyUniversity of PortoPortoPortugal
  4. 4.Centre for Reproductive Genetics Prof. Alberto BarrosPortoPortugal
  5. 5.Department of Genetics, Faculty of MedicineUniversity of PortoPortoPortugal
  6. 6.i3S, Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal

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