Figure 1

Aβ peptides inhibit shear stress-induced elevation of [Ca²⁺]_i in a cell line stably overexpressing PIEZO1. (Panel A) hP1-CL clonal cell line was grown in microfluidic chambers, loaded with Fluo-4 AM, and stimulated with 10 ms pulses of 15 dynes/cm². Changes in fluorescence were monitored by a CCD camera at 1 Hz. Shown are intensity changes at four indicated time points. The maximum response is observed at ∆t = 22 s, long after termination of the stimulus. (Panel B). The L forms of Aβ(1-40) or (1-42) prepared by Peptide Method I at 10 µM to hP1-CL cells inhibited the shear-induced elevation of [Ca²⁺]_i response (4 independent experiments with SEM). (Panel C). PIEZO1 inhibitory potencies of the enantiomeric Aβ peptides (prepared by Peptide Method I) and of the commercially available monomeric peptide AgS, called Aggresure L- Aβ(1-40). The K_i (half-maximal concentration for inhibition) was determined based on the peak response plotted as a function of concentration. Each concentration is an average of 4 independent experiments with SEM. We observed K_i differences between the D and L forms of each peptide (diastereomeric pairs are identified with horizontal double-headed arrows). (Panel D) Monomeric Aβ peptides prepared by Peptide Method II were tested. The monomeric L-Aβ(1-40) was nearly identical to AgS in its ability to inhibit PIEZO1 function with a K_i of ~50 fM (4 independent experiments with SEM).