Cell lines

Platelets

Preparation method

The solubility of this compound in DMSO is >10 mM. General tips for obtaining a higher concentration: Please warm the tube at 37 ℃ for 10 minutes and/or shake it in the ultrasonic bath for a while.Stock solution can be stored below -20℃ for several months.

Reaction Conditions

50 μg/ml, 10 min

Applications

Platelets were activated with A23187 plus calcium, a condition known to lead to calpain-catalyzed proteolysis of ABP and talin. In the absence of inhibitor, A23187 led to complete degradation of ABP and talin. E 64d, the permeant inhibitor, did inhibit intracellular proteolysis. Some inhibition was observed at the lowest concentration tested, 20 μg/ml, and essentially complete inhibition was obtained with 50 μg/ml.

Animal models

Male Sprague–Dawley rats

Dosage form

Intraperitoneal injection, 4 μg

Applications

After E-64d treatment, mice were treated with penicillin to induce recurrent seizures. The result showed that E-64d remarkably reduced the aberrant mossy fiber sprouting in the supragranular region of dentate gyrus and CA3 subfield of hippocampus. In rats without E-64d treatment, there was prominent aggregation of mossy fiber terminals in the dentate gyrus and in the stratum pyramidale of CA3 subfield. In rats treated with E-64d, the aggregation of mossy fiber terminals was remarkably decreased in both the supragranular region of dentate gyrus and CA3 subfield.

Other notes

Please test the solubility of all compounds indoor, and the actual solubility may slightly differ with the theoretical value. This is caused by an experimental system error and it is normal.

E-64d, a membrane permeant derivative of E-64c, a thiol protease inhibitor¹, was tested for ability to inhibit calpain activity in intact platelets.

E-64d inhibits severe acute respiratory syndrome coronavirus (SARS-CoV) and SARS-CoV-2 surface glycoprotein incorporation into pseudotyped vesicular stomatitis virus (VSV) particles in Vero cells, an effect that is reduced by expression of the serine protease TMPRSS2.

E-64c or E-64d also inhibited (lanes 3-8), demonstrating their effect on calpain. When the platelets were incubated with these inhibitors for I0 min and were then washed to remove extracellular inhibitor before lysis, neither E-64c nor leupeptin inhibited proteolysis, but E-64d did inhibit. E-64d was able to penetrate the platelet and was thus not removed by washing.E-64c failed to inhibit proteolysis in intact platelets, but E-64d, the permeant inhibitor, did inhibit intracellular proteolysis.E-64c and E-64d were each able to inhibit the protease activity in lysed platelets. This protease activity has been attributed to calpain by its absolute dependence on Ca²⁺and by inhibition by known inhibitors of calpain. E-64d is able to enter the intact platelet: i) after washing to remove extracellular inhibitor, there was no protease activity detected after platelet lysis, and ii) activation of platelets preincubated with E-64d, but not E-64c, resulted in inhibition of proteolysis by calpain activated in intact platelets by A23187 plus calcium.

Reference:
1. M. Tamai, K. Matsumoto, S. Omura, I. Koyama, Y. Ozawa, K. Hanada J. Pharmacobio-Dyn., 9 (1986), pp. 672–677
2. E. B. McGowan, E. Becker, and T. C. Detwiler, INHIBITION OF CALPAIN IN INTACT PLATELETS BY THE THIOL PROTEASE INHIBITOR E-64d. BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS , Vol. 158, No. 2, 1989
3. Carmen JC, Sinai AP. The Differential Effect of Toxoplasma Gondii Infection on the Stability of BCL2-Family Members Involves Multiple Activities. Front Microbiol. 2011 Jan 24;2:1.