Table 2.

Influence of DHT on the Expression of Lipid-Related Gene Ontologies in hTERT-Immortalized Human Meibomian Gland Epithelial Cells

Ontologies	DHT Genes ↑	Plac Genes ↑	DHT z-score	Plac z-score
Lipid metabolic process	87	43	5.08	−1.94
Cellular lipid metabolic process	71	32	4.76	−2.09
Lipid binding	45	22	2.93	−1.8
Lipid biosynthetic process	34	16	3.03	−1.43
Steroid metabolic process	27	11	4	−0.88
Fatty acid metabolic process	28	6	4.25	−2.28
Lipid transport	16	7	2.44	−0.9
Phospholipid binding	16	6	2.02	−1.45
Sterol metabolic process	15	6	3.42	−0.42
Cholesterol metabolic process	13	6	3.01	−0.17
Steroid biosynthetic process	12	5	2.63	−0.55
Fatty acid biosynthetic process	12	3	2.86	−1.26
Sterol biosynthetic process	9	3	4.08	0.1
Protein amino acid lipidation	9	3	3.17	−0.35
Lipid modification	9	2	2.11	−1.4
Cholesterol biosynthetic process	7	3	3.66	0.59
Acetyl-CoA catabolic process	5	4	2.81	1.82
Acetyl-CoA metabolic process	5	4	2.48	1.54
Steroid dehydrogenase activity	6	2	3.15	0.02
Fatty acid oxidation	7	1	2.57	−1.22
Lipid oxidation	7	1	2.57	−1.22
Lipid homeostasis	6	2	2.23	−0.47
Fatty acid binding	6	1	3.05	−0.76
Steroid dehydrogenase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor	5	2	2.7	0.2

Lipid-related gene ontologies, with some of the highest and lowest z-scores, were selected after the analysis of log-transformed microarray data. A z-score is the statistical rating of the relative expression of gene ontologies, and depicts how much each ontology is over- or underrepresented in a given gene list.⁴⁶ Positive z-scores reflect gene ontology terms with a greater number of genes meeting the criterion than is expected by chance, whereas negative z-scores represent gene ontology terms with fewer genes meeting the criterion than expected by chance. A z-score close to 0 indicates that the number of genes meeting the criterion is approximately the expected number.⁴⁶ z-scores with values >2.0 or <−2.0 are quite significant. Biological process and molecular function ontologies with such z-scores and with ≥6 genes are highlighted in bold. DHT Genes ↑, number of genes upregulated in DHT-treated cells, as compared with those of the placebo group; Plac Genes ↑, number of genes upregulated in placebo (i.e., ethanol vehicle)-treated cells, relative to those of the DHT group; z-score, specific score for the upregulated genes in the placebo- and hormone-treated cells.