| MNDA (myeloid nuclear differentiation antigen) is a PYHIN-family nuclear protein expressed predominantly in monocytes, granulocytes and subsets of B cells, where it functions as an interferon-inducible transcriptional regulator that links pattern-recognition signals to gene programs controlling myeloid differentiation, inflammatory responses and tumor-associated immune phenotypes. The protein contains an N‑terminal pyrin domain that mediates protein–protein interactions in death and inflammatory signaling and a C‑terminal HIN (hematopoietic interferon-inducible nuclear) domain that binds DNA in a sequence-tolerant manner, allowing MNDA to regulate transcription largely through chromatin-associated complexes rather than strict motif-specific binding. MNDA associates with nuclear proteins such as nucleolin (C23) and nucleophosmin/B23 (NPM), and also binds the NPM–MLF1 chimera generated by t(3;5) translocations in myelodysplastic syndrome and acute myeloid leukemia, placing MNDA at nucleolar and non-nucleolar chromatin sites where it can influence transcriptional and apoptotic signaling in myeloid progenitors. Ectopic MNDA expression in MNDA-null K562 cells confers resistance to TRAIL-induced apoptosis without protecting against genotoxic or oxidative stress, indicating a selective role in modulating death receptor pathways and supporting the idea that reduced MNDA levels in myelodysplastic syndromes increase granulocyte–macrophage progenitor sensitivity to TRAIL and contribute to the elevated apoptosis characteristic of these disorders. MNDA is required for full IFNα induction in human monocytes, where it directly controls transcription of type I interferon genes and interferon-stimulated genes by acting as a PYHIN factor that couples innate sensing to nuclear transcriptional machinery. In hepatocellular carcinoma, MNDA expression in tumor-associated myeloid cells drives a protumor immune microenvironment by promoting M2 macrophage polarization; MNDA upregulation in myeloid populations enhances expression of M2-related markers and supports HCC metastasis; and MNDA-high infiltrates correlate with worse clinical outcome, indicating that MNDA acts as a facilitator of M2-skewed, metastasis-supporting macrophage responses in liver cancer. As a myeloid-associated nuclear antigen, MNDA is also emerging as a useful diagnostic and prognostic marker: its expression in B cells is enriched in marginal zone lymphoma compared with other B‑cell non-Hodgkin lymphomas, and immunohistochemical assessment of MNDA in clinical biopsies improves differential diagnosis of nodal marginal zone lymphoma versus follicular and other small B‑cell lymphomas. |
