Role of tick JAK/STAT pathway in response to <i>A</i>. <i>phagocytophilum</i> infection.

<p>The JAK/STAT pathway genes were down-regulated in nymphs, up-regulated in adult female midguts and not affected by bacterial infection in adult female salivary glands, suggesting as corroborated by the treatment of infected tick cells with JAK-STAT inhibitors, that <i>A</i>. <i>phagocytophilum</i> infection decreases immunity in nymphs while inhibiting cell apoptosis in midgut cells to facilitate and establish infection. (A) Annotation of JAK/STAT pathway genes and expression in response to <i>A</i>. <i>phagocytophilum</i> infection. For annotation, gene identifiers were obtained from VectorBase (<a href="http://www.vectorbase.org" target="_blank">www.vectorbase.org</a>) and compared to the corresponding pathways in <i>Drosophila melanogaster</i>, <i>Anopheles gambiae</i>, <i>Aedes aegypti</i> and <i>Homo sapiens</i>. Differential expression (P<0.05) is shown for tick nymphs (N) and adult midguts (G) and salivary glands (SG). (B) <i>A</i>. <i>phagocytophilum</i> DNA levels were determined in infected ISE6 tick cells untreated (Control) or treated for 48 h with STAT (9.2 μM), JAK (400 nM), and STAT (9.2 μM) + JAK (400 nM) inhibitors. Bacterial DNA levels were determined by <i>msp4</i> real-time PCR normalizing against tick 16S rDNA. Results are shown as Ave+SD normalized Ct values and were compared between untreated and treated cells by Student's t-test with unequal variance (*P<0.05; N = 4).