Previous studies provided that Aβ1-42 peptide, a pathological component of Alzheimer's disease (AD), and α-synuclein, the major protein of Lewy bodies in Parkinson's disease (PD), may interact with transcription factors and affect gene transcription. Researchers have revealed that Aβ1-42 can be found in the nucleus, interact with DNA, and change the expression of many genes. It is known that α-synuclein functions as a transcription factor that binds to nuclear DNA and modulates the expression of many genes. Our study aims to investigate whether these peptides directly affect the expression of general transcription factors, contributing to a broader gene expression regulation.Using FpClass and TRRUST databases, common transcription factors were identified for both peptides. HEK-293T cells were overexpressed with α-synuclein protein using plasmids containing the SNCA gene and treated with different doses of Aβ1-42 peptide. After RNA isolations were performed at different time intervals in HEK-293T cells, changes in transcription factor expression in response to Aβ1-42 treatment and α-synuclein overexpression were evaluated by qRT-PCR.The results of our study showed the expression levels of JUN, RELA, FOS, SMAD3, STAT3, and ATF2 co-transcription factors were altered by Aβ1-42 treatment and α-synuclein overexpression, with changes depending on different doses and duration of treatment.Our findings contribute to fundamental knowledge of the intracellular functions of Aβ1-42 and α-synuclein and reveal new insights that will elucidate the pathology of AD and PD.