RESUMO
In order to ensure barrier function, intestinal cells need to respond promptly to biomechanical stimulation and to adapt constantly to physical cues. To this aim, cell membranes are essential and rely extensively on lipid metabolism and turnover. These can be tuned via nutrition, pharmacological treatment, or exposure to xenobiotics, however, knowledge on the impact of lifestyle and diet on intestinal cells' biomechanical compliance is relatively limited. Building on this, two intestinal cell models (non-transformed human colon epithelial cells HCEC-1CT and the colon adenocarcinoma cell line HT-29) were systematically compared in terms of cholesterol content, membrane fluidity, actin cytoskeletal organization, expression of mechano-gated PIEZO1 channels and caveolin-1. Biomechanical compliance was evaluated with the application of fluid shear stress (force response 0.75-1.5 dyn/cm2). As model substances the food contaminant mycotoxin alternariol (AOH, 0.01-10 µM) was chosen in virtue of its putative structural analogy with cholesterol. AOH was compared to the cholesterol lowering agent lovastatin (LOVA, 0.01-10 µM) and to water-soluble cholesterol (MßCD-CHOL, 0.01-10 µg/ml). Exposure to AOH, LOVA and MßCD-CHOL coherently modulated membrane cholesterol, expression of PIEZO1 and caveolin-1 as well as the formation of actin stress fibers. These effects were functionally relevant since they modified the force response profile to fluid shear stress (morphological adaption and [Ca2+]i). In sum, we could demonstrate a novel role for exogenous or endogenous molecules in shaping intestinal mechanotransduction via regulation of cholesterol homeostasis and plasma membrane architecture.
