Intestinal lymphatic vasculature is functionally adapted to different drainage regions and is altered by helminth infection.

Abstract

We sought to determine whether the lymphatic vasculature functionally adapts to the organ in which it resides, such as along the gut. Duodenal lymphatic capillaries (lacteals) displayed the most discontinuous tight junction composition within the gut, resulting in a dependence on duodenal lacteals for rapid dietary lipid uptake. Duodenal helminths abrogated these features. Parallel RNA sequencing of lymphatic endothelial cells and mucosa along the intestine revealed that the transcriptomes overlapped in functional profiles. RNA sequencing also identified a putative VEGFR-2/3 signaling gradient that may explain differences in lacteal tight junctions along the small intestine at homeostasis. Transcriptionally, helminth infection triggered antimicrobial and angiogenic responses. While microbial depletion acted additively to helminths on lymphatic restructuring, glucocorticoids partially reversed helminth-induced lacteal changes. This suggests helminths induce lymphangiogenesis and associated lymphatic "zippering" via inflammation. Our study uncovers and explains the superior lipid absorption by duodenal lacteals and how it is compromised by helminths and provides transcriptional insights into lymphatic function along the gut.