This work was supported by the National Institutes of Health: R01HD068901 (PI: A.H.). The authors declare no conflict of interest.

Objective To establish cultures of epithelial cells from all regions of the human epididymis to provide reagents for molecular approaches to functional studies of this epithelium. Design Experimental laboratory study. Setting University research institute. Patient(s) Epididymis from seven patients undergoing orchiectomy for suspected testicular cancer without epididymal involvement. Intervention(s) Human epididymis epithelial cells harvested from adult epididymis tissue. Main Outcome Measure(s) Establishment of a robust culture protocol for adult human epididymal epithelial cells. Result(s) Cultures of caput, corpus, and cauda epithelial cells were established from epididymis tissue of seven donors. Cells were passaged up to eight times and maintained differentiation markers. They were also cryopreserved and recovered successfully. Androgen receptor, clusterin, and cysteine-rich secretory protein 1 were expressed in cultured cells, as shown by means of immunofluorescence, Western blot, and quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The distribution of other epididymis markers was also shown by means of qRT-PCR. Cultures developed transepithelial resistance (TER), which was androgen responsive in the caput but androgen insensitive in the corpus and cauda, where unstimulated TER values were much higher. Conclusion(s) The results demonstrate a robust in vitro culture system for differentiated epithelial cell types in the caput, corpus, and cauda of the human epididymis. These cells will be a valuable resource for molecular analysis of epididymis epithelial function, which has a pivotal role in male fertility.

Mutations in the cystic fibrosis transmembrane conductance regulator () gene cause the inherited disorder cystic fibrosis (CF). Lung disease is the major cause of CF morbidity, though expression levels are substantially lower in the airway epithelium than in pancreatic duct and intestinal epithelia, which also show compromised function in CF. Recently developed small molecule therapeutics for CF are highly successful for one specific mutation and have a positive impact on others. However, the low abundance of transcripts in the airway limits the opportunity for drugs to correct the defective substrate. Elucidation of the transcriptional mechanisms for the locus has largely focused on intragenic and intergenic tissue-specific enhancers and their activating -factors. Here, we investigate whether the low CFTR levels in the airway epithelium result from the recruitment of repressive proteins directly to the locus. Using an siRNA screen to deplete ∼1500 transcription factors (TFs) and associated regulatory proteins in Calu-3 lung epithelial cells, we identified nearly 40 factors that upon depletion elevated CFTR mRNA levels more than 2-fold. A subset of these TFs was validated in primary human bronchial epithelial cells. Among the strongest repressors of airway expression of were Krüppel-like factor 5 and Ets homologous factor, both of which have pivotal roles in the airway epithelium. Depletion of these factors, which are both recruited to an airway-selective -regulatory element at -35 kb from the promoter, improved CFTR production and function, thus defining novel therapeutic targets for enhancement of CFTR.

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