β-Defensins (DEFBs) have a variety of functions. The majority of these proteins were not identified in a recent proteome survey. Neither protein detection nor the analysis of transcriptomic data based on RNA-seq data for three liver cancer cell lines identified any expression products. Extensive investigation into DEFB transcripts in over 70 cell lines offered similar results. This fact naturally begs the question—Why are DEFB genes scarcely expressed? After examining DEFB gene annotation and the physicochemical properties of its protein products, we postulated that regulatory elements could play a key role in the resultant poor transcription of DEFB genes. Four regions containing DEFB genes and six adjacent regions on chromosomes 6, 8, and 20 were carefully investigated using The Encyclopedia of DNA Elements (ENCODE) information, such as that of DNase I hypersensitive sites (DHSs), transcription factors (TFs), and histone modifications. The results revealed that the intensities of these ENCODE features were globally weaker than those in the adjacent regions. Impressively, DEFB-related regions on chromosomes 6 and 8 containing several non-DEFB genes had lower ENCODE feature intensities, indicating that the absence of DEFB mRNAs might not depend on the gene family but may be reliant upon gene location and chromatin structure.

ObjectiveThis study was performed to investigate the effects of age and sex on 10 salivary steroid hormones and analyze the correlations between salivary and plasma hormones.MethodsThe concentrations of 10 salivary steroid hormones in 1090 Chinese adult volunteers were examined using liquid chromatography–tandem mass spectrometry, and a related investigation was performed on the concentrations of salivary hormones in this population.ResultsThe concentrations of androstenedione (A4), 17α-hydroxyprogesterone (17-OHP), aldosterone (ALD), cortisone (COR), corticosterone (CORT), cortisol (F), progesterone (P), and testosterone were significantly different between men and women (Student’s t-test). Differences in 17-OHP and ALD concentrations were highly significant between women in the follicular and luteal phases of their menstrual cycle (Student’s t-test). Five salivary steroid hormones (17-OHP, A4, CORT, COR, and F) significantly decreased with increasing age (Kruskal–Wallis test). A high linear correlation between salivary and plasma 17-OHP, P, A4, and F were observed with obvious sex-related differences (Pearson’s correlation, r > 0.7).ConclusionsOur results provide important knowledge regarding the descriptive characteristics of salivary hormones in relation to age and sex and their correlations with plasma hormones.