ABSTRACT
OBJECTIVE: Asthma is an inflammatory airway disease affecting most of the population in the world. The current medication for asthma relieves airway inflammation but it has serious adverse effects. Biochanin A (BCA), a phytoestrogen, is an active component present in red clover, alfalfa, soy having anti-oxidant and anti-inflammatory properties. BCA was identified as a natural activator of peroxisome proliferator-activated receptor-gamma (PPARγ). METHODS: The study aims to evaluate the effects of BCA in ovalbumin (OVA)-induced murine model of asthma and to study the role of PPARγ. RESULTS: We found that BCA administration reduced the severity of murine allergic asthma as evidenced histologically, and measurement of allergen-specific IgE levels in serum as well as in BAL fluid. BCA also reversed the elevated levels of inflammatory cytokines, cell infiltration, protein leakage into the airways and expression of hemoxygenase-1 in OVA-induced lungs. Further, we confirmed that BCA mediated inhibitory effects are mediated through PPARγ as assessed by treatment with PPARγ antagonist GW9662. CONCLUSION: Our results suggest that BCA is efficacious in a preclinical model of asthma and may have the potential for the treatment of asthma in humans.
Subject(s)
Genistein/therapeutic use , Inflammation/drug therapy , Respiratory Tract Diseases/drug therapy , Animals , Anti-Inflammatory Agents/therapeutic use , Asthma/chemically induced , Asthma/drug therapy , Asthma/genetics , Asthma/pathology , Disease Models, Animal , Female , Inflammation/chemically induced , Inflammation/genetics , Inflammation/pathology , Mice , Ovalbumin , PPAR gamma/genetics , PPAR gamma/metabolism , Respiratory Tract Diseases/chemically induced , Respiratory Tract Diseases/genetics , Respiratory Tract Diseases/pathology , Signal Transduction/drug effects , Signal Transduction/genetics , Treatment OutcomeABSTRACT
The inhibition of polymorphonuclear neutrophils' (PMNs) migration to the source of injury is among the most prominent aspects of immunosuppression following sepsis, although the precise mechanisms involved remain unclear and multifaceted. Increasing evidence connects this immunosuppression to nitric oxide (NO), as NO production is a classic feature of inflammation probably through neutrophil activation and migration. Nitrated fatty acids (NFA) such as 10-nitrooleate (OA-NO2), nitrolinoleic acid etc. produced endogenously by the non-enzymatic reaction of NO with unsaturated fatty acids, are found to be potent activators of the transcription factor, peroxisome proliferator-activated receptor gamma (PPARγ). Upregulation of PPARγ during immunosuppression and the subsequent inhibition of neutrophil migration in sepsis have been reported. However, the interplay of OA-NO2, NO and PPARγ in polymicrobial-induced immunosuppression has not been established. Hence to understand this, we have studied the role of OA-NO2 in blood PMNs migration, the effects of iNOS inhibitor on PMNs migration and PPARγ activity in cecal ligation and puncture (CLP)-induced sepsis in mice. We found increased expression of PPARγ and its DNA-binding activity in the lungs and blood PMNs from CLP mice. CLP or OA-NO2 treatment inhibited PMNs' migration in response to fMLP stimulation. Pharmacological inhibition of iNOS resulted in decreased PPARγ DNA-binding activity with a concomitant increase in the migration of PMNs to the site of infection. OA-NO2 treatment also inhibited the production of inflammatory cytokines (TNFα and IL-1ß) secretion from PMNs stimulated with lipopolysaccharide. We have also established that, OA-NO2 mediated inhibition of PMNs migration in vivo and ex vivo are regulated through PPARγ-dependent pathway. This study further highlights the fact that the activation of PPARγ by the NFA has a pivotal role in PMNs' migration and immunosuppression.
Subject(s)
Chemotaxis/drug effects , Neutrophils/drug effects , Oleic Acids/pharmacology , PPAR gamma/immunology , Sepsis/immunology , Animals , Cecum/surgery , Female , Ligation , Mice, Inbred C57BL , Neutrophils/physiologyABSTRACT
Fibronectin type III domain containing 5 (FNDC5) is a transmembrane protein. Upon cleavage, it yields a peptide called irisin that is supposedly bind to an unknown receptor and facilitates browning of white adipose tissue (WAT). Increased levels of irisin are associated with increased levels of energy expenditure markers PGC-1α, UCP-1, besides abundance of beige adipocytes in WAT. Though varied sizes of irisin were reported in humans and rodents it is not yet clear about the actual size of the irisin produced physiologically. Hence, we cloned and expressed human irisin (32-143 aa of FNDC5) in Escherichia coli based on the proposed cleavage site that yields 12.5â¯kDa peptide to study its antigenicity and other biological functions in vitro. We purified recombinant human irisin (rh-irisin) to 95% homogeneity with simple purification method with a yield of 25â¯mg/g wet cell pellet. rh-irisin has been detected by commercially available antibodies from different sources with similar antigenicity. Biological activity of the rh-irisin was confirmed by using 3T3-L1 pre-adipocyte differentiation by Oil red O staining. Further, rh-irisin treatment on pre-adipocytes showed increased expression of markers associated with energy expenditure. As it is involved in energy expenditure process, it could be considered as potential therapeutic option for various metabolic diseases.
