Stromal-derived factor 1 directly promotes genes expressed
within the ovulatory cascade in feline cumulus oocyte complexes
Julieta L. Rojo
Kelly A. Young
Marina C. Peluffo
Received: 5 January 2018 /Accepted: 26 February 2018 /Published online: 8 March 2018
Springer Science+Business Media, LLC, part of Springer Nature 2018
Purpose We hypothesized that the chemokine SDF1/CXCR4 system was present in feline cumulus-oocyte complexes (COCs)
and that COCs cultured with SDF1 would directly upregulate gene expression in the ovulatory cascade.
Methods Ovaries (n = 50) were obtained from adult domestic cats during the breeding season and COCs were recovered from
antral follicles. Because IVM media triggers cumulus-oocyte expansion, culture conditions needed to be optimized to study
periovulatory genes. After optimization, the effects of 25 ng/ml SDF1 and the CXCR4 inhibitor were examined in a COC culture
for 3, 12, and 24 h.
Results MEM-hepes with 1% of charcoal stripped-FBS was the optimized culture medium, assessed by the expansion of COCs
at 24 h in the gonadotropin (GNT) group but not in the media with serum alone. The mRNA expression of HAS2, TNFAIP6,
PTX3,andAREG peaked at 3 h in GNT group as compared to all other groups (p <0.05).COCsculturedwithSDF1 showed
increased HAS2 and TNFAIP6 mRNA expression at 3 h compared to negative controls and to the CXCR4 inhibitor group.
CXCR4 and SDF1 immunostaining was present in both cumulus cells and the oocyte.
Conclusions These results demonstrate that GNT stimulation upregulates key periovulatory genes and expansion in feline COCs
from antral follicles, and support the use of this culture system to examine molecular processes within the COC. In addition,
SDF1 directly promotes key periovulatory genes in feline COCs, suggesting that the SDF1-CXCR4 pathway may extend its
function beyond a chemoattractant, and may play a direct role within the COC.
Cumulus oocyte complex
The domestic cat (Felis catus) is a species commonly used for
the study of oocyte cryopreservation based on its potential to
serve as a model species for biomedical research and the con-
servation of endangered felids . Because highly conserved
reproductive mechanisms between humans and feline species
exist, cats serve as good models for addressing infertility syn-
dromes in women, such as asynchronous oocyte cytoplasmic
and nuclear maturation, ovarian hypersensitivity, and luteal
dysfunction after gonadotropin therapy . Cat oocytes share
several characteristics with human oocytes: (1) the diameter of
the oocyte proper and the germinal vesicle is equivalent (110
and 45 μm, respectively) in both species; (2) oocytes reach the
metaphase II (MII) stage of meiosis after 24 h in culture; and
(3) both species have a similar nuclear configuration
with a small nucleolus and a fibrillar chromatin [2, 3].
In contrast, these morphological features are distinct or
lacking in the typical laboratory mouse model. Moreover, the
cat offers a unique and valuable model to study molecular
processes within the preovulatory follicle and cumulus-
oocyte complexes (COC), as each animal provides be-
tween 3 and 7 naturally selected preovulatory follicles,
in an Bovulation-ready^ state primed during estrus for the
copulation-triggered LH stimulus. This stage of the cycle,
Electronic supplementary material The online version of this article
(https://doi.org/10.1007/s10815-018-1150-4) contains supplementary
material, which is available to authorized users.
* Marina C. Peluffo
Centro de Investigaciones Endocrinológicas BDr. César Bergadá^
(CEDIE), CONICET, FEI, División de Endocrinología Hospital de
Niños Ricardo Gutiérrez, Gallo 1330, CABA, C1425EFD Buenos
Department of Biological Sciences, California State University Long
Beach, Long Beach, CA 90840, USA
Journal of Assisted Reproduction and Genetics (2018) 35:785–792