Functional Role of Tick ⍺-D-galactosidase in Carbohydrate Metabolism and Red Meat Allergy
Ahmed Mohamed, Gary Crispell, Surendra Sharma, Faizan Tahir, and Shahid Karim
Department of Cell and Molecular Biology, The University of Southern Mississippi, Hattiesburg, MS
Tick-borne red meat allergy is an IgE-mediated delayed hypersensitivity reaction, increasing widespread in tick endemic areas in the United States of America, and worldwide. Bites from the lone-star tick (Amblyomma americanum) are believed to be involved as the source of the sensitization of humans to the oligosaccharide galactose-⍺-1,3-galactose (alpha-gal or α-gal), which is found in most mammalian derived food products, including gelatin, broths, and red meat. The purpose of this study is to functionally characterize the lone-star tick α-D-galactosidase (AGS) enzyme and assess its role in α-gal synthesis. This enzyme cleaves terminal α-galactose moieties from glycoproteins and glycolipids. Hence, we hypothesized that silencing of AGS in the lone-star tick will impair the tick’s ability to synthesize α-gal and overall carbohydrate metabolism. A reverse genetic approach was utilized to characterize the functional role of α-D-galactosidase in carbohydrate metabolism, and to discover its link to red meat allergy. Our results from AGS gene silencing revealed a significant increase in tick weight, supporting a critical functional role in energy utilization. The silencing of AGS had deleterious effects on the downstream genes in the tick galactose metabolism pathway and AGS-silenced ticks ultimately expressed less ⍺-gal due to the reduction of available UDP-galactose.
Furthermore, we are currently conducting experiments in order to further elucidate the role of α-D-galactosidase in tick-host interactions and the possible involvement in the newly described “Red Meat Allergy”.