Inhibition of arachidonate 15-lipoxygenase prevents 4-hydroxynonenal-induced protein damage in male germ cells.
Lipid peroxidation products, such as 4-hydroxynonenal (4HNE), are causative agents responsible for extensive protein damage within the male and female germlines. Recently, we have demonstrated that 4HNE production can initiate the proteolytic degradation of the molecular chaperone Heat Shock Protein A2 (HSPA2) in male germ cells. These events may be partially responsible for HSPA2 deficiency in the spermatozoa of patients that repeatedly fail in vitro fertilization. Given this, mechanisms that limit the production of 4HNE will be highly advantageous for the preservation of male fertility. The propagation of 4HNE in somatic cells has been linked to the enzymatic actions of arachidonate 15-lipoxygenase (ALOX15), a member of the lipoxygenase family of proteins. In view of this association, this study sought to explore ALOX15 as a physiological target to manipulate the levels of 4HNE produced in the male germline. Herein, we have demonstrated that ALOX15 is markedly upregulated in response to oxidative stress in round spermatids and the GC-2 cell line. Pharmacological inhibition of ALOX15 in GC-2 cells resulted in a significant reduction in both mitochondrial and cytoplasmic reactive oxygen species, as well as a dramatic reduction in 4HNE. Importantly, the reduced bioavailability of this aldehyde appears to confer positive downstream effects to its target proteins such that HSPA2 could be protected from damage by 4HNE. Taken together, these results suggest that the actions of ALOX15 are intimately tied to the production of 4HNE. Thus, the ALOX15 protein may be a promising new target for the mitigation of germline oxidative stress.
Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, Discipline of Biological Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
Elizabeth G
EG
Bromfield
Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, Discipline of Biological Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
Bettina P
BP
Mihalas
Priority Research Centre for Cancer Research, Innovation and Translation, Hunter Medical Research Institute, School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, The University of Newcastle, Callaghan, New South Wales, Australia.
Matthew D
MD
Dun
Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, Discipline of Biological Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
R John
RJ
Aitken
School of Biological Sciences, University of Auckland, Auckland, New Zealand.
Eileen A
EA
McLaughlin
Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, Discipline of Biological Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
Jessica L H
JL
Walters
Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, Discipline of Biological Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
Brett
B
Nixon
D000447:Aldehydes / Q000378:metabolism*; D000818:Animals; D001092:Arachidonate 12-Lipoxygenase / Q000378:metabolism*; D001093:Arachidonate 15-Lipoxygenase / Q000378:metabolism*; D002460:Cell Line; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013094:Spermatozoa / Q000378:metabolism*
D000447:Aldehydes; D018840:HSP70 Heat-Shock Proteins; C490434:Hspa2 protein, mouse; D017382:Reactive Oxygen Species; C521960:Alox15 protein, mouse; D001092:Arachidonate 12-Lipoxygenase; C515716:ALOX15 protein, human; D001093:Arachidonate 15-Lipoxygenase; C027576:4-hydroxy-2-nonenal
aldehyde; fertility; germ cell; lipid peroxidation; oxidative stress