DNA damage-inducible transcript 4 (DDIT4) (DDIT4)

DNA damage-inducible transcript 4 (DDIT4), also known as REDD1 or RTP801, is a protein that acts as a potent negative regulator of the mechanistic target of rapamycin complex 1 (mTORC1) pathway (UniProt P58904). It is rapidly induced by various cellular stressors, including hypoxia, DNA damage, and nutrient deprivation, and functions by promoting the activity of the TSC1-TSC2 complex, which in turn inhibits mTORC1 (PubMed: 12242295, 19208815). In clinical contexts, DDIT4 mRNA is a specific target for RNA interference (RNAi) therapy, particularly for ocular diseases such as diabetic macular edema (DME) and age-related macular degeneration (AMD), where its overexpression is linked to retinal cell apoptosis and inflammation (PubMed: 22427542). The drug PF-04523655 (also known as RTP801i-MET) is a synthetic siRNA designed to target and degrade DDIT4 mRNA, thereby reducing protein levels and potentially preserving retinal function (ClinicalTrials.gov: NCT00701181). Beyond ophthalmology, DDIT4 is implicated in the progression of certain cancers and neurodegenerative disorders like Parkinson's disease, where it modulates autophagy and survival pathways (PubMed: 12242295). Therapeutic challenges associated with targeting DDIT4 mRNA include ensuring the specificity of siRNA delivery to the target tissue and managing the potential systemic consequences of modulating a central stress-response regulator (PubMed: 22427542).

Other names

REDD1RTP801Dig2Regulated in development and DNA damage response 1

siRNA-mediated mRNA degradation (RNA interference)