AUTHOR=Reiten Malin R. , Malachin Giulia , Kommisrud Elisabeth , Østby Gunn C. , Waterhouse Karin E. , Krogenæs Anette K. , Kusnierczyk Anna , Bjørås Magnar , Jalland Clara M. O. , Nekså Liv Heidi , Røed Susan S. , Stenseth Else-Berit , Myromslien Frøydis D. , Zeremichael Teklu T. , Bakkebø Maren K. , Espenes Arild , Tranulis Michael A. 

TITLE=Stress Resilience of Spermatozoa and Blood Mononuclear Cells without Prion Protein

JOURNAL=Frontiers in Molecular Biosciences

VOLUME=5

YEAR=2018

URL=https://www.frontiersin.org/journals/molecular-biosciences/articles/10.3389/fmolb.2018.00001

DOI=10.3389/fmolb.2018.00001

ISSN=2296-889X

ABSTRACT=<p>The cellular prion protein PrP<sup>C</sup> is highly expressed in neurons, but also present in non-neuronal tissues, including the testicles and spermatozoa. Most immune cells and their bone marrow precursors also express PrP<sup>C</sup>. Clearly, this protein operates in highly diverse cellular contexts. Investigations into putative stress-protective roles for PrP<sup>C</sup> have resulted in an array of functions, such as inhibition of apoptosis, stimulation of anti-oxidant enzymes, scavenging roles, and a role in nuclear DNA repair. We have studied stress resilience of spermatozoa and peripheral blood mononuclear cells (PBMCs) derived from non-transgenic goats that lack PrP<sup>C</sup> (<italic>PRNP</italic><sup>Ter/Ter</sup>) compared with cells from normal (<italic>PRNP</italic><sup>+/+</sup>) goats. Spermatozoa were analyzed for freeze tolerance, DNA integrity, viability, motility, ATP levels, and acrosome intactness at rest and after acute stress, induced by Cu<sup>2+</sup> ions, as well as levels of reactive oxygen species (ROS) after exposure to FeSO<sub>4</sub> and H<sub>2</sub>O<sub>2</sub>. Surprisingly, PrP<sup>C</sup>-negative spermatozoa reacted similarly to normal spermatozoa in all read-outs. Moreover, <italic>in vitro</italic> exposure of PBMCs to Doxorubicin, H<sub>2</sub>O<sub>2</sub> and methyl methanesulfonate (MMS), revealed no effect of PrP<sup>C</sup> on cellular survival or global accumulation of DNA damage. Similar results were obtained with human neuroblastoma (SH-SY5Y) cell lines stably expressing varying levels of PrP<sup>C</sup>. RNA sequencing of PBMCs (<italic>n</italic> = 8 of <italic>PRNP</italic><sup>+/+</sup> and <italic>PRNP</italic><sup>Ter/Ter</sup>) showed that basal level expression of genes encoding DNA repair enzymes, ROS scavenging, and antioxidant enzymes were unaffected by the absence of PrP<sup>C</sup>. Data presented here questions the <italic>in vitro</italic> cytoprotective roles previously attributed to PrP<sup>C</sup>, although not excluding such functions in other cell types or tissues during inflammatory stress.</p>