The catalytic subunit of cAMP-dependent protein kinase in Taenia solium cysticerci (TsPKA-c): A promising molecular target for the development of novel anti-cysticercosis therapeutics.

Cysticercosis, caused by the larval stage of T. solium, remains a major neglected tropical disease with severe clinical and socioeconomic consequences in endemic regions. Although cyclic AMP-dependent protein kinase (PKA) signaling is fundamental to parasite development and survival, its therapeutic relevance in T. solium has not been comprehensively explored. This study provides an integrated molecular and functional characterization of the T. solium PKA catalytic subunit (TsPKA-c) and evaluates its potential as a novel therapeutic target for cysticercosis control. Recombinant TsPKA-c was successfully expressed in Pichia pastoris and purified in an active form, demonstrating robust kinase activity. Phylogenetic analysis revealed strong evolutionary conservation among cestode PKA homologues, underscoring its essential biological function. Immunohistochemical analysis confirmed stage-specific expression in both larval and adult parasite forms. Optimal enzymatic activity occurred at pH 7.5 and 35°C, with kinetic parameters showing a Km of 36.37 ± 2.64 µM and Vmax of 0.7648 ± 0.013 nmol/min/µg. Pharmacological inhibition experiments identified H89 as a highly potent inhibitor of TsPKA-c (IC50 = 14.55 ± 1.5 µM), exhibiting greater efficacy than PKI (14-22) (IC50 = 23.09 ± 0.5 µM). Both inhibitors induced significant dose- and time-dependent mortality in T. pisiformis cysticerci, with H89 causing rapid lethality. Metabolic analyses demonstrated a marked reduction in glucose uptake following TsPKA-c inhibition, accompanied by alterations in excretory-secretory protein profiles. Collectively, these findings establish TsPKA-c as a critical regulator of parasite metabolism and survival, supporting its strong candidacy as a promising molecular target for the development of novel anti-cysticercosis therapeutic strategies.