Cathelicidin-4

Although the chemical, physical, and nutritional properties of bovine milk have been extensively studied, only a few studies have attempted to characterize milk-synthesizing genes using RNA-seq data. RNA-seq data was collected from 21 Holstein samples, along with group information about milk production ability; milk yield; and protein, fat, and solid contents. Meta-analysis was employed in order to generally characterize genes related to milk production. In addition, we attempted to investigate the relationship between milk related traits, parity, and lactation period. We observed that milk fat is highly correlated with lactation period; this result indicates that this effect should be considered in the model in order to accurately detect milk production related genes. By employing our developed model, 271 genes were significantly (false discovery rate [FDR] adjusted p-value<0.1) detected as milk production related differentially expressed genes. Of these genes, five (albumin, nitric oxide synthase 3, RNA-binding region (RNP1, RRM) containing 3, secreted and transmembrane 1, and serine palmitoyltransferase, small subunit B) were technically validated using quantitative real-time polymerase chain reaction (qRT-PCR) in order to check the accuracy of RNA-seq analysis. Finally, 83 gene ontology biological processes including several blood vessel and mammary gland development related terms, were significantly detected using DAVID gene-set enrichment analysis. From these results, we observed that detected milk production related genes are highly enriched in the circulation system process and mammary gland related biological functions. In addition, we observed that detected genes including caveolin 1, mammary serum amyloid A3.2, lingual antimicrobial peptide, cathelicidin 4 (CATHL4), cathelicidin 6 (CATHL6) have been reported in other species as milk production related gene. For this reason, we concluded that our detected 271 genes would be strong candidates for determining milk production.

Supplemental oxygen is often used to treat neonates with respiratory disorders. Preclinical studies have demonstrated that neonatal hyperoxia injures the distal small intestine and activates nuclear factor-κB (NF-κB). Cathelicidin inhibits NF-κB activity and ameliorates lipopolysaccharide-induced intestinal barrier disruption in rats. Sprague-Dawley rat pups were reared in either room air (RA) or hyperoxia (85% O2) and were randomly treated with low-dose cathelicidin (4 mg/kg, LDC) and high-dose cathelicidin (HDC, 8 mg/kg) in 0.05 mL of normal saline (NS) administered intraperitoneally on postnatal days 1-6. The following six groups were obtained: RA + NS, RA + LDC, RA + HDC, O2 + NS, O2 + LDC, and O2 + HDC. The animals were sacrificed and the terminal ileum was removed for Western blot and histological analyses on postnatal day 7. The hyperoxia-reared rats exhibited significantly lower body weights, higher intestinal injury scores, lower occludin and ZO-1 expression, higher intestinal permeability and inducible IκB kinase inhibitor (IKKi) and NF-κB expression than the RA-reared rats. Cathelicidin treatment attenuated intestinal injury as evidenced by lower intestinal injury scores and intestinal permeability and higher intestinal barrier protein expression. The decrease in intestinal injury was accompanied by a decrease in IKKi and NF-κB. Cathelicidin attenuated hyperoxia-induced intestinal injury in the newborn rats, likely through NF-κB activity inhibition.

Cathelicidin synthesized by bone marrow cells plays an important role in neutralizing invading pathogens. In the present study, the myeloid cathelicidin cDNA from Bubalus bubalis has been cloned and characterized. RNA from bone marrow of buffalo ribs was extracted, reverse transcribed and amplified using specific pair of primer designed from published cathelicidin-4 cDNA sequences of Bos taurus popularly known as indolicidin. An expected amplified product of 517 bp was obtained, which was cloned and sequenced. Comparison of buffalo cathelicidin and indolicidin sequences reveal that the open reading frames (ORF) of both these two congeners consist of 435 nucleotides with 28 divergent nucleotides and the translated proteins of 144 amino acid residues. Fourteen amino acid residues were found to be dissimilar between these two congeners. The molecular mass of buffalo cathelicidin calculated from the deduced amino acid sequence was 16.23 kDa, which is in close proximity of indolicidin. The sequence comparison with known B. taurus cathelicidin congeners again show 70.8-92.9% identity at nucleotides level and 65-88.3% identity at amino acids level. The maximum similarity of buffalo cathelicidin both at nucleotides level (92.9%) and protein level (88.3%) was found to be with indolicidin. Phylogenetic tree analysis at nucleotides and amino acids level indicate that buffalo, cattle, sheep, pig and equine cathelicidin sequences comprise one clade which are distantly related with human, rabbit and murine cathelicidins. It may be reasonably concluded that buffalo possess the ancestral gene of cathelicidin like that of bovine species.