DIMet 0.1.0

A tool for Differential Isotope-labeled targeted Metabolomics

DIMet: Differential Isotope-labeled targeted Metabolomics

Introduction

DIMet is a bioinformatics pipeline for differential analysis of targeted isotope-labelled data.

DIMet supports the analysis of full metabolite abundances and isotopologue contributions, and allows to perform it either in the differential comparison mode or as a time-series analysis. As input, the DIMet accepts three types of measures: a) isotopologues’ contributions, b) fractional contributions (also known as mean enrichment), c) full metabolites’ abundances. Specific functions process each of the three types of measures separately.

Note: DIMet is intended for downstream analysis of tracer metabolomics data that has been corrected for the presence of natural isotopologues. Make sure you that the metabolomics platform provides you the output of the correction procedure before using this pipeline.

Provided datasets

Datasets, configuration and bash commands corresponding to the results presented in the manuscript "DIMet: An open-source tool for Differential analysis of targeted Isotope-labeled Metabolomics data " are available on Zenodo. Download and uncompress the file datasets_manuscript_DIMet.

You can use the files in data/Cycloserine_data/raw, data/LDHAB-Control_data/raw and data/LDHAB-Control_data/integration_files and perform the analyses through the Galaxy version of DIMet, which contains the general instructions to do so.

Otherwise, after downloading and uncompressing the datasets folder, place it inside any directory NOT being the DIMet directory. Perform the analyses in a command line environment, by placing yourself inside datasets_manuscript_DIMet and running the .sh executable files to reproduce the analyses. The rest of the present document is therefore addressed to users desiring to work in command line environment.

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Installing DIMet

System Requirements

DIMet installation requires an Unix environment with python 3.9. It was tested under Linux and MacOS environments.

Installation

The full installation process should take less than 15 minutes on a standard computer.

Via pip command: pip install dimet

Or if you are a developer working in a local cloned version, you can install: pip install -e .

Code organization

• src/processing directory contains the implemented high-level analysis scripts that produced the tables for the DIMet paper
• src/visualization : directory contains the implemented high-level scripts that produced the figures in the DIMet paper
• src/data directory contains the python classes for data initialization
• src/method directory contains the python classes for configuration handling
• src/tests directory contains unit tests
• tools directory contains venv setup scripts. Alternatively, the yml file is also provided in this directory, to perform the installation via conda.

Running unit tests

• with pytest, by running pytest from DIMet
• Place yourself in DIMet/tests and execute python -m unittest

Using DIMet

DIMet has a Galaxy version. It also runs in a command line environment. The runtime is dependent on the hardware, the number of metabolites in the dataset, and the selected options.

Running analyses on the manuscript data

Make sure you have activated your virtual environment, or DIMet conda environment. After downloading the data from Zenodo, you have a folder named datasets_manuscript_DIMet. You have inside, two .sh files. Each .sh file will run sequentially, different analyses for its respective dataset. Make them executable

chmod a+x *.sh

and finally:

./run_LDHAB-Control.sh
./run_Cycloserine_timeseries.sh

Running analyses on your data

To run any analysis on your own data, first your files have to be preprocessed. Preprocessing includes, in this order:

• (a) The correction by the abundance of naturally occurring isotopologues by external tools such IsoCor, ElMaven, AccuCor, etc).

• (b) The normalization by internal standard and/or the normalization by amount of material and/or the formatting of the quantification tables.

For the (b) type of preprocessing we offer our accompanying tool Tracegroomer. Only use DIMet when your data has already underwent the complete preprocessing, as it will not be carried out by DIMet.

The following sections will help you to understand the general expected organization of your input data and configuration files. Further minimal examples can also be downloaded from Zenodo

General organization of the input data and configuration (when in command line environment)

Input data and configuration files that were used to generate the figures in the DIMet paper are provided as examples of how the DIMet pipeline can be used.

Input format

DIMet, in its command line environment, takes a folder of hierarchically organized folders containing the data and the configuration files. Below there is a minimal structure example, MYPROJECT must be replaced by your project name, for example "Brain" or your field of study. The word DATANAME1 represents an experiment, and must be replaced by a meaningful noun. More than one subfolder in the data folder can be added, but make sure to elaborate the respective -and unambiguous- configuration files.

MYPROJECT
├── config
│   ├── analysis
│   │   ├── dataset
│   │   │   └── DATANAME1_data.yaml
│   │   ├── differential_analysis_DATANAME1.yaml
│   │   ├── ... # ---> other 'analysis configuration' yml files
│   │   └── pca_analysis_DATANAME1.yaml
│   ├── general_config_differential_analysis_DATANAME1.yaml
│   ├──  ... # ---> other 'general configuration' yml files
│   └── general_config_pca_analysis_DATANAME1.yaml
└── data
    └── DATANAME1_data
        └── raw
            ├── AbundanceCorrected.csv
            ├── Isotopologues_proportions.csv
            ├── MeanEnrichment.csv
            └── DATANAME1_metadata.csv

Data

Using the aliases shown in the example structure above, the data folder contains:

• DATANAME1_data that is a folder named accordingly with the experiment (for example Cycloserine_data or LDHAB-Control_data or example1_data). In turn this DATANAME1_data, contains:
  • One raw subfolder where your quantifications and metadata are located. Note that for practical reasons we used the name "raw", but as explained above, this data has been already preprocessed before using DIMet.
  • After running any analysis, one processed subfolder is generated, which contains the tables split by cellular compartment, cleaned from rows containing only NaN, and also cleaned from rows containing only 0.

Configuration files

There are three types of configuration files, all of them in json format:

1. dataset configuration files

2. analysis configuration files

3. general configuration files

A given dataset configuration file refers to the corresponding quantifications and metadata files that are present in the data folder, and is located in the config/analysis/dataset/ folder.

The analysis configuration file should be located in the config/analysis/ folder Thus, an analysis configuration file indicates the name of the dataset configuration file, which in turn points to the input data in the data folder.

The general configuration file points to the analysis configuration file, and is located in config.

Further examples of these configuration files, with their respective minimal datasets are provided on Zenodo

Getting help

For any information or help running DIMet, you can get in touch with:

• Macha Nikolski
• Benjamin Dartigues
• Johanna Galvis

LICENSE MIT

Copyright (c) 2023 

Johanna Galvis (1,3)    ([e-mail])
Joris Guyon (2)         ([e-mail])
Benjamin Dartigues (1)	([e-mail])	 
Florian Specque (3)	  	([e-mail])
Slim Karkar (1,3)       ([e-mail])
Helge Hecht             ([e-mail])
Bjorn Gruening          ([e-mail])
Thomas Daubon (3)       ([e-mail])  
Macha Nikolski (1,3)    ([e-mail])

(1) CBiB - University of Bordeaux,
146, rue Leo Saignat, 33076 Bordeaux, France

(2) University of Bordeaux, INSERM, BPH U1219, Bordeaux, France

(3) CNRS, IBGC - University of Bordeaux,
1, rue Camille Saint-Saens, 33077 Bordeaux, France

(4) Galaxy Europe

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