Expression analysis of the NLRP gene family suggests a role in human preimplantation development.
BACKGROUND
The NLRP (Nucleotide-binding oligomerization domain, Leucine rich Repeat and Pyrin domain containing) family, also referred to as NALP family, is well known for its roles in apoptosis and inflammation. Several NLRPs have been indicated as being involved in reproduction as well.


METHODS
We studied, using the unique human gametes and embryo materials, the expression of the NLRP family in human gametes and preimplantation embryos at different developmental stages, and compared the expression levels between normal and abnormal embryos using real-time PCR.


RESULTS
Among 14 members of the NLRP family, twelve were detected in human oocytes and preimplantation embryos, whereas seven were detected in spermatozoa. Eight NLRPs (NLRP4, 5, 8, 9, 11, 12, 13, and 14) showed a similar expression pattern: their expression levels were high in oocytes and then decreased progressively in embryos, resulting in a very low level in day 5 embryos. However, NLRP2 and NLRP7 showed a different expression pattern: their expression decreased from oocytes to the lowest level by day 3, but increased again by day 5. The expression levels of NLRP5, 9, and 12 were lower in day 1 abnormal embryos but higher in day3 and day5 arrested embryos, when compared with normal embryos at the same stages. NLRP7 was down-regulated in day 1 and day 5 abnormal embryos but over-expressed in day3 arrested embryos.


CONCLUSIONS
According to our results, different NLRPs possibly work in a stage-dependent manner during human preimplantation development.
Zhang
Pu
P
Department of Bioscience and Nutrition at Novum, Karolinska Institutet, Huddinge, Sweden.
Dixon
Morag
M
Zucchelli
Marco
M
Hambiliki
Fredwell
F
Levkov
Lev
L
Hovatta
Outi
O
Kere
Juha
J
D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis* / Q000235:genetics; D001755:Blastocyst / Q000378:metabolism*; D017931:DNA Primers / Q000737:chemistry; D005260:Female; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D005854:Germ Cells / Q000378:metabolism; D006801:Humans; D008297:Male; D009865:Oocytes / Q000378:metabolism; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013094:Spermatozoa / Q000378:metabolism; D013997:Time Factors
D048868:Adaptor Proteins, Signal Transducing; D017931:DNA Primers