In vitro metabolic activation of vitamin D3 by using a multi-compartment microfluidic liver-kidney organ on chip platform

Jannick Theobald,Stefan Wölfl,Mohamed A Abu El Maaty,Bernhard Wetterauer,Michael Wink,Xinlai Cheng,Nico Kusterer

doi:10.1038/s41598-019-40851-9

Jannick Theobald, Stefan Wölfl + Show 5 more

Open Access

https://doi.org/10.1038/s41598-019-40851-9

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Journal: Scientific Reports	Publication Date: Mar 15, 2019
Citations: 36	License type: open-access

Affiliation: Heidelberg University

Abstract

Organ-on-chip platforms provide models that allow the representation of human physiological processes in cell-based miniaturized systems. Potential pre-clinical applications include drug testing and toxicity studies. Here we describe the use of a multi-compartment micro-fluidic chip to recapitulate hepatic vitamin D metabolism (vitamin D to 25-hydroxyvitamin D) and renal bio-activation (25-hydroxyvitamin D to 1,25-dihydroxyvitamin D) in humans. In contrast to cultivation in conventional tissue culture settings, on-chip cultivation of HepG2 and RPTEC cells in interconnected chambers, used to mimic the liver and kidneys, respectively, resulted in the enhanced expression of vitamin D metabolizing enzymes (CYP2R1, CYP27B1 and CYP24A1). Pump-driven flow of vitamin D3-containing medium through the microfluidic chip produced eluate containing vitamin D3 metabolites. LC-MSMS showed a strong accumulation of 25-hydroxyvitamin D. The chip eluate induced the expression of differentiation markers in HL-60 (acute myeloid leukemia) cells, assessed by qPCR and FACS analysis, in a manner similar to treatment with reference standards indicating the presence of fully activated 1,25 dihydroxyvitamin D, although the latter was not detected in the eluate by LC-MSMS. Interestingly, 25-hydroxyvitamin D by itself led to weak activation of HL-60 cells suggesting that 25-hydroxyvitamin D is also an active metabolite. Our experiments demonstrate that complex metabolic interactions can be reconstructed outside the human body using dedicated organ-on-chip platforms. We therefore propose that such systems may be used to mimic the in vivo metabolism of various micronutrients and xenobiotics.

Highlights

Vitamin D deficiency is a global pandemic that affects approximately one billion people worldwide[1]
Recent genome-wide association studies have identified single-nucleotide polymorphisms (SNPs) in genes encoding proteins involved in vitamin D synthesis, transport, and metabolism that influence vitamin D status in humans[9,10]
Data illustrate the ability of this molecule to induce apoptosis and differentiation, modulate metabolism, as well as inhibit proliferation and metastasis[2,5,6,7,32]

Summary

Introduction

Vitamin D deficiency is a global pandemic that affects approximately one billion people worldwide[1]. A major limitation in vitamin D-based chemotherapy is the need for supra-physiological doses to achieve substantial anti-tumor effects[6] Such doses lead to hypercalcemia, hampering their clinical utility. Recent genome-wide association studies have identified single-nucleotide polymorphisms (SNPs) in genes encoding proteins involved in vitamin D synthesis, transport, and metabolism that influence vitamin D status in humans[9,10]. This is of major importance in determining subject-specific response to vitamin D supplementation, since different subjects possessing differing sets of SNPs would require varying doses of vitamin D compounds to elevate circulatory 25(OH)D levels to a desirable range, or to elicit specific biological effects.

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