Molecular characterization of kisspeptin gene and effect of nano-encapsulted kisspeptin-10 on reproductive maturation in Catla catla.

Kisspeptin, a member of the RF-amide-related peptide family, has emerged recently as an essential gatekeeper of various reproductive processes via its ability to activate kisspeptin receptors at puberty. In this study, the kiss1 gene and its receptor kiss1rb were cloned and characterized from the brain of Catla catla. Further, the effects of kissppetin-10 (K-10) and chitosan-encapsulated K-10 nanoparticles (CK-10) on gene expression were assessed. The full-length complementary DNA sequence of kiss1 is 754 bp with an open reading frame of 351 bp that encodes a putative protein of 116 amino acids. The kiss1rb complementary DNA is 1,280 bp long and contains a 5'-untranslated region of 30 bp, 3'-untranslated region of 149 bp, and an open reading frame (open reading frame) of 1,101 bp. The expression patterns of kiss1 and kiss1rb messenger RNA (mRNA) in basal tissues revealed that they are mainly expressed in the brain, pituitary gland, and gonads. CK-10 nanoparticles with a particle size of 125 nm and a zeta potential of 36.45 mV were synthesized and compared with K-10. Chitosan nanoparticles showed 60% entrapment efficiency for K-10. The mRNA expression of reproductive genes (GnRH, LH, and FSH) in fish injected with K-10 declined after 6 h, whereas those injected with CK-10 showed controlled and a sustained surge of mRNA expression of these genes with a peak at 12 h. Histologic examination of ovaries indicated a pronounced effect of CK-10 on maturation and gonadal development. The study reports that this sustained release delivery system will help in increasing the half-life of K-10 and other therapeutic protein drugs in the biological system. Besides, the nanoformulation developed in the present study may be useful for developing therapies against various reproductive dysfunctions in vertebrates.