g. myeloid cells [29]. Indeed, some reports indicate that PRL from the pituitary gland induces read more production of nitric oxide and TNF-�� in murine peritoneal M?, a process involving protein tyrosine kinases, MAP kinases and Ca++ channeling [30]. On the other hand, the inhibition of inducible nitric oxide synthase expression by pituitary PRL has previously correlated with JAK-STAT-5b activation and the suppression of IRF-1 in lung fibroblasts [15]. Using an acute inflammation model induced with LPS in mice and characterized by proinflammatory cytokine synthesis, it has been shown that PRLr mRNA is differentially expressed [13]. Nevertheless, the same cytokines induce the expression of PRLr isoforms that may allow PRL to inhibit the nitrosative stress in pulmonary fibroblasts [15].

Therefore, we hypothesized that the expression of an autocrine loop of PRL might play an important role during the inflammatory response in monocytes. To study the inflammatory response with LPS, the human monocytic leukemia-derived THP-1 cell differentiated with phorbolmyristate has been useful [22,31]. LPS is instantaneously recognized by TLR4 expressed by monocytes [22,31,32]. TLR4 is associated with MD-2 on the cell surface and this is required for induction of inflammatory cytokines. Additionally, LPS-binding protein (LBP) and CD14 are involved in the responses to LPS. CD14 binds LBP and delivers LPS-LBP to the TLR4-MD-2 complex. TLR4 is known to activate two signaling pathways: the myeloid differentiation primary response gene 88-dependent pathways and the TIR-containing adapter inducing IFN��-dependent pathway.

Signaling pathways via TLR4 mediated by these adapter molecules conclude in the activation of NF-kB, and/or mitogen-activated protein kinases, and/or the transcription factor IFN regulatory factor 3. Activation of these molecules regulates the expression of diverse inflammatory genes as type I IFN [33]. LPS is a specific ligand for TLR4, but cytokines and hormones may cooperate to enhance eradication of pathogens from the circulation AV-951 system and tissue sites [34]. In this work, in order to avoid masked effects of other molecules released by differentiated M? into the culture medium, we used undifferentiated monocytes including the cell culture line THP-1 and fresh monocytes isolated from subjects likely with different genotypes. We used primers to amplify the conserved region of PRLr mRNA from all isoforms that retain 175 bp of the exons 7, 8 and 9 (GenBank ID: “type”:”entrez-nucleotide”,”attrs”:”text”:”NM_001204315.1″,”term_id”:”324073310″,”term_text”:”NM_001204315.1″NM_001204315.1), including: LF, intermediate isoform (IF), and short isoforms, ��SF1, SF1a, SF1b, ��4-SF1b, ��4/6-SF1a, SF1c; and to detect the PRL mRNA, exons 4-5 were amplified.