Slirp effect affects sperm's swimming ability
A gene known to affect hormone action in breast and prostate cancer cells has now been proven to have an impact on male fertility, according to research by a team including cancer specialists from The University of Western Australia.
Further work at the UWA-affiliated Western Australian Institute for Medical Research (WAIMR), which originally discovered the SLIRP gene, has resulted in a deeper understanding of the gene's role which could have ramifications for couples experiencing infertility.
UWA Winthrop Professor Peter Leedman, who leads WAIMR's Laboratory for Cancer Medicine, said his research team, headed by UWA Assistant Professor Shane Colley, found that mice without the SLIRP gene - a so-called 'knock-out' gene - had one third fewer offspring than normal mice and produced significantly fewer sperm which could be described as 'good swimmers'.
"In collaboration with researchers at UWA and Monash University, we crossed normal females with SLIRP knock-out males and found the litter size was reduced by 30 per cent," Dr Colley said.
Electron microscopy of the sperm without the SLIRP gene found a disruption in the middle section of their structure, which was associated with the sperm swimming more slowly.
The research in mice could have an impact on human couples. Infertility affects approximately one in eight couples globally; in half these cases the cause is attributable to the male partner.
Despite medical and scientific advances in the understanding of infertility, the exact cause is often still unclear. With further studies in humans, if reduced SLIRP production turns out to be an important cause of infertility, assessment of SLIRP gene levels in male sperm could help explain why some couples are unable to have a baby.
"This discovery may eventually have practical ramifications for couples who are not having any luck conceiving naturally," Professor Leedman said.
"For example, if our studies in men with infertility demonstrate a key role for SLIRP, then it is feasible that SLIRP testing could help streamline treatment options - eg going more directly to IVF (in vitro fertilisation) treatment rather than continuing to try conceiving without medical intervention for another six to 12 months.
"Hopefully this might reduce some of the pain and anxiety experienced by these couples."
A research paper by the WAIMR team and collaborators, "Loss of the nuclear receptor corepessor SLIRP compromises male fertility," has been published in the online scientific journal PLOS ONE.