Do you know the sex of your cells?

Abstract

Do you know the sex of your cells? Not a question that is frequently heard around the lab bench, yet thanks to recent research is probably one that should be asked. It is self-evident that cervical epithelial cells would be derived from female tissue and prostate cells from a male subject (exemplified by HeLa and LnCaP, respectively), yet beyond these obvious examples, it would be true to say that the sex of cell lines derived from non-reproductive tissue, such as lung, intestine, kidney, for example, is given minimal if any thought. After all, what possible impact could the presence of a Y chromosome have on the biochemistry and cell biology of tissues such as the exocrine pancreatic acini? Intriguingly, recent evidence has suggested that far from being irrelevant, genes expressed on the sex chromosomes can have a marked impact on the biology of such diverse tissues as neurons and renal cells. It is also policy of AJP-Cell Physiology that the source of all cells utilized (species, sex, etc.) should be clearly indicated when submitting an article for publication, an instruction that is rarely followed (http://www.the-aps.org/mm/Publications/Info-For-Authors/Composition). In this review we discuss recent data arguing that the sex of cells being used in experiments can impact the cell's biology, and we provide a table outlining the sex of cell lines that have appeared in AJP-Cell Physiology over the past decade.

Sex inclusion in basic research drives discovery

“…[Note, however, that this may not be a factor in experiments using immortalized cell lines, which may have become chromosomally unstable, rendering it impossible to determine their original sex (16). ]…”

Focus on preclinical sex differences will not address women’s and men’s health disparities

“…Many cell lines derived from male donor cells have been shown to have lost Y-chromosomal gene expression, eliminating chromosomal sex as a meaningful variable (see table 1 in ref. 15). Some have even proposed that cell lines are distinct species.…”

Determining Membrane Protein Topology Using Fluorescence Protease Protection (FPP)

“…The glycoside toxin, digitonin, is extracted from the plant Digitalis purpurea. Digitonin has an affinity for cholesterol rich membranes, where it leads to selective membrane permeabiliztion 14,16 ( Figure 1). In addition to allowing exit of small cytosolic components, digitonin permeabilization also permits the entry of exogenous molecules, such as proteinase K or trypsin.…”

“…In addition to allowing exit of small cytosolic components, digitonin permeabilization also permits the entry of exogenous molecules, such as proteinase K or trypsin. The FPP protocol takes advantage of the fact that the plasma membrane contains up to 80% of cellular cholesterol 17 , whereas other organelles, such as ER, Golgi, endosomes, mitochondria, which have very low cholesterol content, remain intact 14 . The selective incorporation of cholesterol into the plasma membrane has been observed in many eukaryotic cells, permitting the use of digitonin-dependent plasma membrane permeabilization in such diverse eukaryotic species as S. cerevisiae to human 14,18 .…”

“…The FPP protocol takes advantage of the fact that the plasma membrane contains up to 80% of cellular cholesterol 17 , whereas other organelles, such as ER, Golgi, endosomes, mitochondria, which have very low cholesterol content, remain intact 14 . The selective incorporation of cholesterol into the plasma membrane has been observed in many eukaryotic cells, permitting the use of digitonin-dependent plasma membrane permeabilization in such diverse eukaryotic species as S. cerevisiae to human 14,18 . The FPP assay provides a simple, rapid and fairly robust means of determining (a) whether a protein is membrane bound/associated or freely diffusible in the cytosol and (b) which domain of a membrane protein faces the cytosol or organelle lumen.…”