Penn researchers track defective sperm epigenome linked to male infertility
The study was carried out in collaboration between the Wayne State University School of Medicine, the CReATe Fertility Centre and the University of Massachusetts Amherst.
The purpose of the study was to find out if non-targeted RNA sequencing was sensitive and specific enough to detect the presence of microbes, a task which current techniques that use targeted culturing are incapable of doing. The researchers took 85 samples of semen and extracted the RNA of the sperm. This was then sequenced using their enhanced technology. The RNA sequences that were not part of the human genome were matched to microbial genes. These reads were used to create a picture of the microbes found in each semen sample. The findings
They found that all the samples showed similar levels of bacteria normally found in the male reproductive tract. These come from 11 genera, forming part of 4 phyla. Only one exception was found, which was quite different from all the other microbial reads.
Specifically, this specimen harbored a large number of bacteria of the species Streptococcus agalactiae and S. dysgalactiae. S. agalactiae is a bacterial species that is linked to many newborn infections, as well as infections occurring in pregnancy and after delivery. It is also the cause of many deaths among babies born prematurely. Moreover, it also causes serious infection in elderly adult patients. The presence of this bacteria in sperm is therefore of considerable concern. Implications
At present, the presence of microbes in the male reproductive organs is diagnosed by culture techniques. However, most of the microbes typically found to infect this tract are fastidious in their culture requirements, meaning that they cannot be cultured under the usual laboratory conditions.
On the other hand, RNA sequencing is a much more reliable and now more widely available technique, which is also becoming more affordable by the day. The use of this technology is likely to provide a better idea of the bacteria and other microbes inhabiting the human body. The researchers say, “We show that non-targeted sequencing of human sperm RNA has the potential to provide a profile of micro-organisms (bacteria, viruses, archaea). This information was recovered from the data typically cast aside as part of routine nucleic acid sequencing.”
The clinical picture shows that infections with S. agalactiae are on the rise and are becoming more severe than before. Other microbes are also causing more frequent infections in newborns and adults. In this situation, says researcher Stephen Krawetz, “Non-targeted human sperm RNA sequencing data may, in addition to providing fertility status, prove useful as a diagnostic for microbial status." Journal reference:
wanson, G.M., Moskovtsev, S., Librach, C. et al. What human sperm RNA-Seq tells us about the microbiome. Journal of Assisted Reproduction and Genetics, January 2020. https://doi.org/10.1007/s10815-019-01672-x. https://link.springer.com/article/10.1007%2Fs10815-019-01672-x
Also in Industry News
How to decide whether or not to start treatment for prostate cancer?
Analysis of the SARS-CoV-2 proteome via visual tools
$65m investment increases British Patient Capital’s exposure to life sciences and health technology