Small Heat Shock Proteins have a Paramount Role in Trypanosoma cruzi Infection Impacting Intestinal Homeostasis of an insect vector of Chagas Disease

Abstract Rhodnius prolixus , an insect vector of Chagas disease, ingests blood meals several-fold its own body weight. This nutritional overload triggers specific adaptive responses that prevent or remediate damage from multiple stressors, including oxidative, osmotic, and microbial challenges. Transcriptomic analysis of first-instar nymph guts revealed five members of the Small Heat-Shock Protein (sHSP) family that were highly expressed after blood meals but were downregulated upon Trypanosoma cruzi infection. sHSPs are proteins involved in cellular homeostasis and stress responses. Simultaneous knockdown of all five sHSPs profoundly disrupted insect physiology, causing decreased actin filament network formation, interrupted peristalsis, blocked ER expansion, and reduced ER-mitochondria association, while increasing reactive oxygen species generation and inducing premature epithelial cell mitosis. This apparent loss of gut homeostasis was recapitulated by trypanosome infection and, conversely, sHSP silencing in infected insects increased parasite numbers. Taken together, our data reveal a paramount role for sHSPs in gut cell homeostasis following blood meals and support the hypothesis that sHSP expression down regulation represents an adaptive manipulation of the insect host by the parasite. Significance Statement This study demonstrates that sHSPs serve as critical regulators of digestive physiology and intestinal homeostasis in a Chagas disease vector. These proteins orchestrate key processes including ROS production and cytoskeletal and endoplasmic reticulum organization, directly influencing T. cruzi proliferation. Conversely, the parasite manipulates their expression, revealing sHSPs as novel determinants of vector competence. Between 6 and 7 million people worldwide suffer from Chagas Disease, with 10,000 deaths annually. Although vector-borne transmission has declined, oral transmission is increasing, underscoring the urgent need to understand molecular factors governing vector competence. Our findings position sHSPs as promising targets for developing innovative strategies to control disease transmission.