The carbohydrate Galα1-3Galβ1-(3)4GlcNAc-R (α-Gal) is produced in all mammals except for humans, apes and old world monkeys that lost the ability to synthetize this carbohydrate. Therefore, humans can produce high antibody titers against α-Gal. Anti-α-Gal IgE antibodies have been associated with tick-induced allergy (i.e. α-Gal syndrome) and anti-α-Gal IgG/IgM antibodies may be involved in protection against malaria, leishmaniasis and Chagas disease. The α-Gal on tick salivary proteins plays an important role in the etiology of the α-Gal syndrome. However, whether ticks are able to produce endogenous α-Gal remains currently unknown. In this study, the Ixodes scapularis genome was searched for galactosyltransferases and three genes were identified as potentially involved in the synthesis of α-Gal. Heterologous gene expression in α-Gal-negative cells and gene knockdown in ticks confirmed that these genes were involved in α-Gal synthesis and are essential for tick feeding. Furthermore, these genes were shown to play an important role in tick-pathogen interactions. Results suggested that tick cells increased α-Gal levels in response to Anaplasma phagocytophilum infection to control bacterial infection. These results provided the molecular basis of endogenous α-Gal production in ticks and suggested that tick galactosyltransferases are involved in vector development, tick-pathogen interactions and possibly the etiology of α-Gal syndrome in humans.

• MeSH
• alfa-galaktosidasa genetika   metabolismus   MeSH
• Anaplasma phagocytophilum patogenita   MeSH
• ehrlichióza genetika   metabolismus   MeSH
• galaktosyltransferasy metabolismus   MeSH
• genom genetika   MeSH
• HL-60 buňky MeSH
• infekce přenášené vektorem MeSH
• interakce hostitele a patogenu genetika   MeSH
• klíště mikrobiologie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• proteiny členovců metabolismus   MeSH
• sekvence aminokyselin MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The obligate intracellular pathogen, Anaplasma phagocytophilum, is the causative agent of life-threatening diseases in humans and animals. A. phagocytophilum is an emerging tick-borne pathogen in the United States, Europe, Africa and Asia, with increasing numbers of infected people and animals every year. It is increasingly recognized that intracellular pathogens modify host cell metabolic pathways to increase infection and transmission in both vertebrate and invertebrate hosts. Recent reports have shown that amino acids are central to the host-pathogen metabolic interaction. In this study, a genome-wide search for components of amino acid metabolic pathways was performed in Ixodes scapularis, the main tick vector of A. phagocytophilum in the United States, for which the genome was recently published. The enzymes involved in the synthesis and degradation pathways of the twenty amino acids were identified. Then, the available transcriptomics and proteomics data was used to characterize the mRNA and protein levels of I. scapularis amino acid metabolic pathway components in response to A. phagocytophilum infection of tick tissues and ISE6 tick cells. Our analysis was focused on the interplay between carbohydrate and amino acid metabolism during A. phagocytophilum infection in ISE6 cells. The results showed that tick cells increase the synthesis of phosphoenolpyruvate (PEP) from tyrosine to control A. phagocytophilum infection. Metabolic pathway analysis suggested that this is achieved by (i) increasing the transcript and protein levels of mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M), (ii) shunting tyrosine into the tricarboxylic acid (TCA) cycle to increase fumarate and oxaloacetate which will be converted into PEP by PEPCK-M, and (iii) blocking all the pathways that use PEP downstream gluconeogenesis (i.e., de novo serine synthesis pathway (SSP), glyceroneogenesis and gluconeogenesis). While sequestering host PEP may be critical for this bacterium because it cannot actively carry out glycolysis to produce PEP, excess of this metabolite may be toxic for A. phagocytophilum. The present work provides a more comprehensive view of the major amino acid metabolic pathways involved in the response to pathogen infection in ticks, and provides the basis for further studies to develop novel strategies for the control of granulocytic anaplasmosis.

• MeSH
• aminokyseliny metabolismus   MeSH
• Anaplasma phagocytophilum účinky léků   genetika   metabolismus   patogenita   MeSH
• anaplasmóza MeSH
• apoptóza MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• buněčné linie MeSH
• citrátový cyklus MeSH
• fosfoenolpyruvát metabolismus   farmakologie   MeSH
• fosfoenolpyruvátkarboxykinasa (závislá na ATP) metabolismus   MeSH
• genom bakteriální MeSH
• glukoneogeneze MeSH
• glykolýza MeSH
• interakce hostitele a patogenu fyziologie   MeSH
• klíště mikrobiologie   MeSH
• kyselina oxaloctová metabolismus   MeSH
• messenger RNA genetika   MeSH
• metabolické sítě a dráhy genetika   MeSH
• metabolismus sacharidů MeSH
• mitochondrie metabolismus   MeSH
• proteomika metody   MeSH
• serin metabolismus   MeSH
• transkriptom MeSH
• tyrosin metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH