The pathogenic protist Trypanosoma cruzi uses kissing bugs as invertebrate hosts that vectorize the infection among mammals. This parasite oxidizes proline to glutamate through two enzymatic steps and one nonenzymatic step. In insect vectors, T. cruzi differentiates from a noninfective replicating form to nonproliferative infective forms. Proline sustains this differentiation, but to date, a link between proline metabolism and differentiation has not been established. In T. cruzi, the enzymatic steps of the proline-glutamate oxidation pathway are catalyzed exclusively by the mitochondrial enzymes proline dehydrogenase [TcPRODH, EC: 1.5.5.2] and Δ1-pyrroline-5-carboxylate dehydrogenase [TcP5CDH, EC: 1.2.1.88]. Both enzymatic steps produce reducing equivalents that are able to directly feed the mitochondrial electron transport chain (ETC) and thus produce ATP. In this study, we demonstrate the contribution of each enzyme of the proline-glutamate pathway to ATP production. In addition, we show that parasites overexpressing these enzymes produce increased levels of H2O2, but only those overexpressing TcP5CDH produce increased levels of superoxide anion. We show that parasites overexpressing TcPRODH, but not parasites overexpressing TcP5CDH, exhibit a higher rate of differentiation into metacyclic trypomastigotes in vitro. Finally, insect hosts infected with parasites overexpressing TcPRODH showed a diminished parasitic load but a higher percent of metacyclic trypomastigotes, when compared with controls. Our data show that parasites overexpressing both, PRODH and P5CDH had increased mitochondrial functions that orchestrated different oxygen signaling, resulting in different outcomes in relation to the efficiency of parasitic differentiation in the invertebrate host.

中文翻译：

---

脯氨酸脱氢酶的高表达改变了线粒体功能并增加了体外和昆虫载体中的克氏锥虫分化

致病性原生生物克氏锥虫使用接吻虫作为无脊椎动物宿主，在哺乳动物中传播感染。这种寄生虫通过两个酶促步骤和一个非酶促步骤将脯氨酸氧化为谷氨酸。在昆虫载体中，T. cruzi 从非感染性复制形式到非增殖性感染形式进行区分。脯氨酸维持这种分化，但迄今为止，尚未建立脯氨酸代谢和分化之间的联系。在 T. cruzi 中，脯氨酸-谷氨酸氧化途径的酶促步骤完全由线粒体酶脯氨酸脱氢酶 [TcPRODH，EC：1.5.5.2] 和 Δ1-吡咯啉-5-羧酸脱氢酶 [TcP5CDH，EC：1.2.1.88] 催化]。两个酶促步骤都会产生能够直接供给线粒体电子传递链 (ETC) 的还原当量，从而产生 ATP。在这项研究中，我们展示了脯氨酸-谷氨酸途径的每种酶对 ATP 生产的贡献。此外，我们发现过度表达这些酶的寄生虫会产生更高水平的 H2O2，但只有那些过度表达 TcP5CDH 的寄生虫会产生更高水平的超氧阴离子。我们表明，过表达 TcPRODH 的寄生虫，而不是过表达 TcP5CDH 的寄生虫，在体外表现出更高的分化为亚环鞭毛虫的速率。最后，与对照相比，被过度表达 TcPRODH 的寄生虫感染的昆虫宿主表现出寄生虫负荷减少，但中转锥鞭毛体的百分比更高。我们的数据显示寄生虫过度表达两者，