Overall, this is a study with potential, but the following points need to be considered.

Major comments:

1. Fig. 1D: this Venn diagram is misleading and should be better replaced by two simpler Venn's comparing all target genes at 24 h with 48 h and then listing up- and down-regulated genes. In fact, this info is already contained in Fig. 1C, i.e. Fig. 1D may not be necessary at all.

2. Fig. 1E: This heatmap indicates an effect of the vehicle, i.e. most likely of cell culture condition on basal expression of the 50 displayed genes. this effect should be followed up for all expressed genes, in order to differentiate between cell culture effects and 1,25D effects.

3. It is unclear, why the transcriptome analysis does not follow the standard of being performed in triplicate. Thus, a third dataset is missing. This will have major impact on the statistics and conclusions of the manuscript and is absolutely essential.

4. it is unclear, why the Abstract highlights one gene (DDIT4), while the focus of the manuscript is transcriptome-wide.

5. Please use only FDR and not adj. p-values. Regular p-values are less informative and should be replaced by FDR calculations.

Minor comments:

1. Please define every abbreviation at its first time use and stay consistent. For example, 1,25(OH)2D3 is defined differently in the Abstract and Introduction.

2. All gene and mRNA abbreviations should be in italic, this applies also to tables and figures. Please use only gene names based on HUGO nomenclature.

3. Please stay precise with vitamin D metabolite nomenclature. Thus, 1,25(OH)2D3 should not be called vitamin D.

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