IL21 antisense RNA 1 (non-protein coding) (IL21-AS1)

IL21 antisense RNA 1 (IL21-AS1) is a long non-coding RNA transcribed from the antisense strand of the human IL21 gene locus on chromosome 4q27[2][3]. It does not encode a protein, but instead regulates gene activity through epigenetic mechanisms. IL21-AS1 binds to the promoter region of the IL21 gene and interacts with proteins such as hnRNPU and CREB-binding protein (CBP), increasing histone H3 acetylation at the IL21 promoter and thereby activating IL21 transcription[1]. This activity promotes the differentiation of T follicular helper (Tfh) cells and contributes to the aberrant activation of immune responses seen in diseases such as systemic lupus erythematosus (SLE)[1][3]. Increased expression or activity of IL21-AS1 has also been implicated in tumor biology, such as ovarian cancer, where it drives immune evasion and tumor progression by regulating CD24 expression, in part by acting as a competing endogenous RNA (ceRNA) for certain microRNAs and enhancing hypoxia-inducible factor 1-alpha (HIF1α) effects[4]. Currently, there are no drugs directly targeting IL21-AS1, but experimental studies using antisense oligonucleotides to inhibit IL21-AS1 demonstrate disease-relevant effects on immune cell differentiation and cytokine production[1].

Other names

IL21 antisense RNA 1lncRNA IL21-AS1IL21-AS1 (non-protein coding)

Not applicable (no direct approved drugs); experimental silencing of IL21-AS1 using antisense oligonucleotides decreases IL21 expression and modulates immune responses[1].