title: Pinocembrin attenuates lipopolysaccharide-induced inflammatory responses in Labeo rohita macrophages via the suppression of the NF-κB signalling pathway.
abstract: Pinocembrin is a flavonoid that has been reported to exhibit various pharmacological and biological activities including antimicrobial, antioxidant, and anti-inflammatory. To explore the anti-inflammatory activity of pinocembrin in a fish cell line, we investigated its ability to regulate the inflammatory mediators elevated by lipopolysaccharide (LPS) in Labeo rohita head-kidney (HK) macrophages. HK macrophages of L. rohita were treated with LPS (1 μg mL(-1)) in the presence or absence of pinocembrin. We examined the inhibitory effect of pinocembrin on LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production. The inhibitory effect of pinocembrin on nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) was investigated by RT-PCR and western blot. The effect of pinocembrin on pro-inflammatory cytokines (tumour necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β)) and anti-inflammatory cytokine IL-10 was investigated by ELISA and RT-PCR. The phosphorylation of three mitogen activated protein kinases (MAPKs) ERK, JNK, and p38 was analysed by western blot. Pinocembrin inhibited LPS-induced productions of NO and PGE2, and also markedly inhibited TNF-α, IL-1β, iNOS, and COX-2 production in a concentration-dependent manner. In addition, TNF-α and IL-1β mRNA expression levels decreased significantly, while IL-10 mRNA expression increased (P < 0.05) with pinocembrin pre-treatment. RT-PCR and western blot analysis showed that pinocembrin decreased both the mRNA and protein expression levels of LPS-induced iNOS and COX-2 in HK macrophages. Pinocembrin suppressed the phosphorylation of MAPK in LPS-stimulated HK macrophages. Further, pinocembrin significantly inhibited LPS-induced NF-κB transcriptional activity via the attenuation of IκBα degradation. Taken together, pinocembrin reduced the levels of pro-inflammatory mediators, such as iNOS, COX-2, TNF-α, and IL-1β, by inhibiting NF-κB activation via the suppression of ERK and p38 phosphorylation, and by attenuating the degradation of IκBα. These results suggest that pinocembrin is a potential novel candidate for the treatment of inflammatory conditions in L. rohita macrophages.
authors: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, South Korea; Dept. of Zoology, Kundavai Nachiyar Government Arts College for Women (Autonomous), Thanjavur, Tamil Nadu, India.
authors: Sib Sankar
authors: SS
authors: Giri
authors: School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
authors: Shib Sankar
authors: SS
authors: Sen
authors: Dept. of Zoology, Kundavai Nachiyar Government Arts College for Women (Autonomous), Thanjavur, Tamil Nadu, India. Electronic address: drvsukumar@gmail.com.
authors: Venkatachalam
authors: V
authors: Sukumaran
authors: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, South Korea. Electronic address: parksec@snu.ac.kr.
authors: Se Chang
authors: SC
authors: Park
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D003530:Cyprinidae; D005393:Fish Diseases / Q000139:chemically induced / Q000517:prevention & control*; D044950:Flavanones / Q000494:pharmacology*; D007249:Inflammation / Q000139:chemically induced / Q000517:prevention & control / Q000662:veterinary*; D008070:Lipopolysaccharides / Q000502:physiology; D008264:Macrophages / Q000276:immunology; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D000893:Anti-Inflammatory Agents; D044950:Flavanones; D008070:Lipopolysaccharides; D016328:NF-kappa B; C016063:pinocembrin
keywords: Labeo rohita; Lipopolysaccharide; NF-κB signalling pathway; Pinocembrin; macrophages