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From materials science, it is known that the differences in the annealing temperature is the main factor that mostly influences La (Takai et al., 2003, Cançado et al., 2006). In analogy, controlling the pyrolysis temperature and Lestaurtinib australia during residues burning might be a key aspect to reproduce the TPI-BC nanostructure.
Conflict of interest
Acknowledgements The authors acknowledge Cassiano Rabelo e Silva for technical assistance. This work was supported by CAPES-PNPD (grant no. 23038.007147/2011-60) and CNPq (grant no. 473840/2012-0). We also acknowledge financial support from the State Agencies of Minas Gerais (FAPEMIG), Amazonas (FAPEAM) and Rio de Janeiro (FAPERJ).
Introduction Avian thrombocytes serve a similar hemostatic function as mammalian platelets and are the most numerous of all chicken leukocytes, playing an integral role in innate immunity (Horiuchi et al., 2004). Thrombocytes express a variety of cytokines and chemokines involved in the inflammatory immune response. As part of the pro-inflammatory innate response, thrombocytes express genes for interleukin (IL)-1β, IL-6, IL-8, IL-12 and cyclooxygenase-2 (COX-2) (Ferdous et al., 2008, Ferdous and Scott, 2015, Scott and Owens, 2008, St Paul et al., 2012). Thrombocytes also express anti-inflammatory cytokines including IL-10 and transforming growth factor (TGF)-β (St Paul et al., 2012), as well as Toll-like receptors (TLRs) 1LA, 1LB, 2-2, 3, 4, 5, 7, 15 and 21 (Ferdous et al., 2008, Ferdous et al., 2016, Scott and Owens, 2008, St Paul et al., 2012). The TLRs recognize pathogen-associated molecular patterns that are essential components of pathogen survival [e.g. Gram-negative bacterial lipopolysaccharide (LPS), Gram-positive bacterial flagellin, bacterial and viral CpG-containing DNA] and some endogenous proteins released during infection (e.g. Heat Shock Protein-60, -70, and fibrinogen) (Akira and Takeda, 2004). Thrombocytes bind bacterial LPS through TLR4, which initiates an inflammatory response (Ferdous et al., 2008, Scott and Owens, 2008). Scott and Owens reported that LPS exposure activated the nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK) signal pathways, and this led to increased gene expression of IL-6 and COX-2, with increased production of prostaglandin (PG) E2 (Scott and Owens, 2008). The two studies by our laboratory (Ferdous et al., 2008, Scott and Owens, 2008) were the first published reports to show increased pro-inflammatory gene expression in thrombocytes resulting from exposure to LPS. Scott and Owens showed that inhibition of MEK1/2 by PD98059 blocked LPS-induced gene expression, implicating the involvement of this pathway in the expression of pro-inflammatory responses (Scott and Owens, 2008). That study also demonstrated that inhibition of inhibitor of kappa B kinase (IKK) with BMS345541 significantly reduced LPS-induced gene expression, documenting the involvement of the NFκB pathway in the thrombocyte pro-inflammatory response. The current study focused on the effects of inhibiting specific signaling molecules in two mitogen-activated protein kinase (MAPK) pathways that are implicated in the expression of IL-6 in response to LPS. IL-6 initiates an inflammatory response to pathogens, activates both T and B lymphocytes, and promotes the differentiation of monocytes into macrophages (Burdin et al., 1995, Gessani et al., 1993, Rincon et al., 1997). In this study, SB203580 was used to inhibit p38, which is directly downstream of MEK3/6 in one of the MAPK pathways. An inhibitor was used to suppress the activity of extracellular-signal-regulated kinase (ERK), which is directly downstream of MEK1/2 in another MAPK pathway. These signal molecules were chosen for inhibition because previous studies in our laboratory have demonstrated the involvement of MEK in pro-inflammatory gene expression via ERK activation, but it was undetermined what role the p38 MAPK pathway would have in chicken thrombocyte gene expression. Previously, Scott and Owens were able to inhibit COX-2 gene expression if MEK1/2 was blocked by PD98059 (Scott and Owens, 2008). IL-6 gene expression was unaffected by this inhibitor at the concentration used. Also, there was no prior information regarding direct ERK or p38 MAPK inhibition on innate responses initiated by LPS. It was supposed, but unknown, that blocking ERK instead of MEK1/2 would lead to the same altered gene expression previously observed (Scott and Owens, 2008). This particular pathway, unlike the p38 MAPK pathway, has usually been associated with cell growth and differentiation rather than initiation of pro-inflammatory responses (Chae et al., 2005). The p38 MAPK pathway, on the other hand, has been linked to induction of pro-inflammatory gene expression (Widmann et al., 1999). In addition to inhibitors for ERK and p38 MAPK, we also used the two inhibitors employed by Scott and Owens for analysis of activated and released proteins in the MAPK and NFκB pathways (Scott and Owens, 2008). Experiments were conducted to gather more information on TLR4-linked pathways, gene expression and production of bioactive mediators in chicken thrombocytes.