I would like to do an IF of alpha1-syntrophin on PE brain tissue but I detect no signal.

I already tried 2 different ways to proceed antigen retrieval (AR): heat in citrate buffer at 95°C or incubation with trypsin at 37°C, and without AR. I tried with or without permeabilization in 0,3% Triton. I tried 2 different secondary antibodies coupled with fluorochrome (AF488 and AF790).

Any idea on what should I try next ?