IGF-1 attenuates LPS induced pro-inflammatory cytokines expression in buffalo (Bubalus bubalis) granulosa cells

• Published in: Molecular immunology 2015-03, Vol.64 (1), p.136-143
• Main Authors: Onnureddy K, Ravinder, Onteru, Suneel Kumar, Singh, Dheer
• Format: Article
• Language: English
• Subjects: Animals; Aromatase - genetics; Aromatase - metabolism; Bubalus bubalis; Buffalo; Buffaloes - genetics; Cell Nucleus - drug effects; Cell Nucleus - metabolism; Cell Proliferation - drug effects; Crosstalk; Cytokines - genetics; Cytokines - metabolism; Down-Regulation - drug effects; Extracellular Signal-Regulated MAP Kinases - metabolism; Female; Gene Expression Regulation - drug effects; Granulosa cells; Granulosa Cells - cytology; Granulosa Cells - drug effects; Granulosa Cells - enzymology; Granulosa Cells - metabolism; Humans; IGF-1; Inflammation Mediators - metabolism; Insulin-Like Growth Factor I - pharmacology; Lipopolysaccharides - pharmacology; LPS; Models, Biological; NF-kappa B - metabolism; Phosphorylation - drug effects; Protein Transport - drug effects; Proto-Oncogene Proteins c-akt - metabolism; Real-Time Polymerase Chain Reaction; Signal Transduction - drug effects; Signaling; Time Factors
• ISSN: 0161-5890; 1872-9142
• DOI: 10.1016/j.molimm.2014.11.008

•Endocrine signaling competes with immune signaling and impairs ovarian function.•Crosstalk between TLR and IGF-1 signaling in granulosa cells is possible.•Immune signaling (TLRs) predominate over the endocrine signaling under NEB.•Optimum IGF-1 level could prevent impaired granulosa cell function. Interaction between immune and endocrine system is a diverse process influencing cellular function and homeostasis in animals. Negative energy balance (NEB) during postpartum period in dairy animals usually suppresses these systems resulting in reproductive tract infection and infertility. These negative effects could be due to competition among endocrine and immune signaling pathways for common signaling molecules. The present work studied the effect of IGF-1 (50ng/ml) on LPS (1μg/ml) mediated pro-inflammatory cytokine expression (IL-1β, TNF-α, IL-6) and aromatase (CYP19A1) genes’ expressions as well as proliferation of buffalo granulosa cells. The crosstalk between LPS and IGF-1 was also demonstrated through studying the activities of downstream signaling molecules (ERK1/2, Akt, NF-κB) by western blot and immunostaining. Gene expression analysis showed that IGF-1 significantly reduced the LPS induced expression of IL-1β, TNF-α and IL-6. LPS alone inhibited the CYP19A1 expression. However, co-treatment with IGF-1 reversed the inhibitory effect of LPS on CYP19A1 expression. LPS alone did not affect granulosa cell proliferation, but co-treatment with IGF-1, and IGF-1 alone enhanced the proliferation. Western blot results demonstrated that LPS caused the nuclear translocation of the NF-κB and increased the phosphorylation of ERK1/2 and Akt maximum at 15min and 60min, respectively. Nonetheless, co-treatment with IGF-1 delayed LPS induced phosphorylation of ERK1/2 (peak at 120min), while promoting early Akt phosphorylation (peak at 5min) with no effect on NF-κB translocation. Overall, IGF-1 delayed and reversed the effects of LPS, suggesting that high IGF-1 levels may combat infection during critical periods like NEB in postpartum dairy animals.