title: Expression and activation of caspase-6 in human fetal and adult tissues.
abstract: Caspase-6 is an effector caspase that has not been investigated thoroughly despite the fact that Caspase-6 is strongly activated in Alzheimer disease brains. To understand the full physiological impact of Caspase-6 in humans, we investigated Caspase-6 expression. We performed western blot analyses to detect the pro-Caspase-6 and its active p20 subunit in fetal and adult lung, kidney, brain, spleen, muscle, stomach, colon, heart, liver, skin, and adrenals tissues. The levels were semi-quantitated by densitometry. The results show a ubiquitous expression of Caspase-6 in most fetal tissues with the lowest levels in the brain and the highest levels in the gastrointestinal system. Caspase-6 active p20 subunits were only detected in fetal stomach. Immunohistochemical analysis of a human fetal embryo showed active Caspase-6 positive apoptotic cells in the dorsal root ganglion, liver, lung, kidney, ovary, skeletal muscle and the intestine. In the adult tissues, the levels of Caspase-6 were lower than in fetal tissues but remained high in the colon, stomach, lung, kidney and liver. Immunohistological analyses revealed that active Caspase-6 was abundant in goblet cells and epithelial cells sloughing off the intestinal lining of the adult colon. These results suggest that Caspase-6 is likely important in most tissues during early development but is less involved in adult tissues. The low levels of Caspase-6 in fetal and adult brain indicate that increased expression as observed in Alzheimer Disease is a pathological condition. Lastly, the high levels of Caspase-6 in the gastrointestinal system indicate a potential specific function of Caspase-6 in these tissues.
authors.affiliation: Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada ; The Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Quebec, Canada.
authors.forename: Nelly
authors.initials: N
authors.lastname: Godefroy
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Foveau
authors.forename: Steffen
authors.initials: S
authors.lastname: Albrecht
authors.forename: Cynthia G
authors.initials: CG
authors.lastname: Goodyer
authors.forename: Andréa C
authors.initials: AC
authors.lastname: LeBlanc
mesh_terms: D000328:Adult; D017209:Apoptosis; D020170:Caspase 1 / Q000378:metabolism; D053178:Caspase 6 / Q000378:metabolism*; D004789:Enzyme Activation; D005260:Female; D005333:Fetus / Q000166:cytology / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D009928:Organ Specificity; D021122:Protein Subunits / Q000378:metabolism
chemical_list: D021122:Protein Subunits; D053178:Caspase 6; D020170:Caspase 1