Exploring the possible role of estradiol in the regulation of reproductive phase-dependent expression of NOD-like receptors in female Channa punctata

Inflammatory responses are modulated by sex steroids, and hence, not surprisingly, in seasonally breeding organisms, the immune responses are reported to vary according to the reproductive phases. NOD-like receptors (NLRs) act as intracellular sentinels and play a key role in inflammation. Interestingly, to date, there are no reports on their reproductive season-dependent expression and their regulation by sex steroids in teleosts. In the current study, the expression of NOD-like receptors (NLRs) in primary and secondary lymphoid tissues in female Channa punctata during different reproductive phases has been investigated. It was observed that NLRs show a dramatic increase in expression during the spawning phase of Channa punctata. Since estradiol is the primary sex steroid in females that shows the highest plasma level during the reproductively active phase, we investigated whether estradiol was responsible for the increased transcription of NLRs. The effect of estradiol on NLR expression in female Channa punctata was diverse, depending upon the lymphoidic tissue, dose, duration, and mode of estradiol treatment. However, the increased expression of NLRs in the spawning phase could not be attributed to estradiol alone as evident from the study. Other factors acting alone or collaborating with estrogen might be involved in the increased NLR expression during spawning phase in Channa punctata.

Automated summary

The expression of NOD-like receptors (NLRs) in female Channa punctata varies during different reproductive phases, with a dramatic increase during the spawning phase. The role of estradiol, the primary sex steroid in females, in the increased transcription of NLRs is diverse and depends on various factors.