Despite the remarkable clinical responses achieved with immune checkpoint blockade therapy, the response rate is relatively low and only a subset of patients can benefit from the treatment. Aberrant RNA accumulation can mediate IFN signaling and stimulate an immune response, suggesting that targeting RNA decay machinery might sensitize tumor cells to immunotherapy. With this in mind, we identified an RNA exoribonuclease, XRN1, as a potential therapeutic target to suppress RNA decay and stimulate antitumor immunity. Silencing of XRN1 suppressed tumor growth in syngeneic immunocompetent mice and potentiated immunotherapy efficacy, while silencing of XRN1 alone did not affect tumor growth in immunodeficient mice. Mechanistically, XRN1 depletion activated IFN signaling and the viral defense pathway; both pathways play determinant roles in regulating immune evasion. Aberrant RNA-sensing signaling proteins (RIG-I/MAVS) mediated the expression of IFN genes, as depletion of each of them blunted the elevation of antiviral/IFN signaling in XRN1-silenced cells. Analysis of pan-cancer CRISPR-screening data indicated that IFN signaling triggered by XRN1 silencing is a common phenomenon, suggesting that the effect of XRN1 silencing may be extended to multiple types of cancers. Overall, XRN1 depletion triggers aberrant RNA-mediated IFN signaling, highlighting the importance of the aberrant RNA-sensing pathway in regulating immune responses. These findings provide the molecular rationale for developing XRN1 inhibitors and exploring their potential clinical application in combination with cancer immunotherapy. Significance: Targeting XRN1 activates an intracellular innate immune response mediated by RNA-sensing signaling and potentiates cancer immunotherapy efficacy, suggesting inhibition of RNA decay machinery as a novel strategy for cancer treatment.

While much evidence suggests that type 2 diabetes mellitus increases the risk of Parkinson’s disease (PD), the relationship between type 1 diabetes mellitus (T1DM) and PD is unclear. To study their association, we performed a two-sample Mendelian randomization (MR) using the following statistical methods: inverse variance weighting (IVW), MR-Egger, weight median, and weighted mode. Independent datasets with no sample overlap were retrieved from the IEU GWAS platform. All the MR methods found a lower risk of PD in T1DM (IVW—OR 0.93, 95% CI 0.91–0.96, p = 3.12 × 10⁻⁵; MR-Egger—OR 0.93, 95% CI 0.88–0.98, p = 1.45 × 10⁻²; weighted median—OR 0.93, 95% CI 0.89–0.98, p = 2.76 × 10⁻³; and weighted mode—OR 0.94, 95% CI 0.9–0.98, p = 1.58 × 10⁻²). The findings were then replicated with another independent GWAS dataset on T1DM (IVW—OR 0.97, 95% CI 0.95–0.99, p = 3.10 × 10⁻³; MR-Egger—OR 0.96, 95% CI 0.93–0.99, p = 1.08 × 10⁻²; weighted median—OR 0.97, 95% CI 0.94–0.99, p = 1.88 × 10⁻²; weighted mode—OR 0.97, 95% CI 0.94–0.99, p = 1.43 × 10⁻²). Thus, our study provides evidence that T1DM may have a protective effect on PD risk, though further studies are needed to clarify the underlying mechanisms.

Purpose: DNA methylation alterations are widespread in acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS), some of which appear to have evolved independently of somatic mutations in epigenetic regulators. Although the presence of somatic mutations in peripheral blood can predict the risk of development of AML and MDS, its accuracy remains unsatisfactory.Experimental Design: We performed global DNA methylation profiling in a case control study nested within the Singapore Chinese Health Study to evaluate whether DNA methylation alterations were associated with AML/MDS development. Targeted deep sequencing and methylated DNA immunoprecipitation sequencing (MeDIP-seq) were performed on peripheral blood collected a median of 9.9 years before diagnosis of AML or MDS, together with age-matched still-healthy individuals as controls.Results: Sixty-six individuals who developed AML or MDS displayed significant DNA methylation changes in the peripheral blood compared with 167 age- and gender-matched controls who did not develop AML/MDS during the follow-up period. Alterations in methylation in the differentially methylation regions were associated with increased odds of developing AML/MDS.Conclusions: The epigenetic changes may be acquired independently and before somatic mutations that are relevant for AML/MDS development. The association between methylation changes and the risk of pre-AML/MDS in these individuals was considerably stronger than somatic mutations, suggesting that methylation changes could be used as biomarkers for pre-AML/MDS screening.

Nigrostriatal iron accumulation is a hallmark of ageing and neurodegenerative diseases, but the molecular mechanisms regulating iron deposition in the human brain remain unclear. Identifying genes linked to iron accumulation could reveal new pathways for neuroprotection and therapeutic targeting. We performed a discovery-replication transcriptome-wide association study (TWAS), integrating GWAS data for quantitative susceptibility mapping and T2∗ MRI measures (n = 29,579) with expression quantitative trait locus data for the substantia nigra, putamen, and caudate. Single-tissue analyses were complemented by multi-tissue TWAS, colocalisation, and summary Mendelian randomisation (SMR + HEIDI) to evaluate biological plausibility and causal evidence. Functional enrichment and comparison with ageing and Parkinson's disease transcriptomic datasets were conducted. We identified 230 genes associated with nigrostriatal iron, of which 40 were replicable. Of these, 32 had no previous reported links to brain iron. Replicated genes converged on metal ion transport and inflammatory pathways, with notable associations involving calcium channel (CACNB2), zinc transporter (SLC39A12/ZIP12), and sorting nexin (SNX31) genes. SMR + HEIDI and colocalisation highlighted several putatively causal genes, including SNX31 and TMEM206. Overlap with Parkinson's disease substantia nigra differential expression data highlighted a subset of genes (5.22%), particularly SLC39A12. Our data implicate a role of coordinated interactions among iron, zinc, and calcium homoeostasis pathways in nigrostriatal iron accumulation in the general population, with region-specific regulation differing between substantia nigra and dorsal striatum. These findings nominate new mechanistic targets for experimental validation in neurodegeneration. Supported by the Singapore National Medical Research Council and SingHealth/Duke-NUS Academic Medical Centre.

Purpose:DNA methylation alterations are widespread in acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS), some of which appear to have evolved independently of somatic mutations in epigenetic regulators. Although the presence of somatic mutations in peripheral blood can predict the risk of development of AML and MDS, its accuracy remains unsatisfactory.Experimental Design:We performed global DNA methylation profiling in a case control study nested within the Singapore Chinese Health Study to evaluate whether DNA methylation alterations were associated with AML/MDS development. Targeted deep sequencing and methylated DNA immunoprecipitation sequencing (MeDIP-seq) were performed on peripheral blood collected a median of 9.9 years before diagnosis of AML or MDS, together with age-matched still-healthy individuals as controls.Results:Sixty-six individuals who developed AML or MDS displayed significant DNA methylation changes in the peripheral blood compared with 167 age- and gender-matched controls who did not develop AML/MDS during the follow-up period. Alterations in methylation in the differentially methylation regions were associated with increased odds of developing AML/MDS.Conclusions:The epigenetic changes may be acquired independently and before somatic mutations that are relevant for AML/MDS development. The association between methylation changes and the risk of pre-AML/MDS in these individuals was considerably stronger than somatic mutations, suggesting that methylation changes could be used as biomarkers for pre-AML/MDS screening.

Mutations in mitochondrial protein CHCHD2 and its paralog CHCHD10 were identified in patients with Parkinson disease (PD), amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD) or Alzheimer disease (AD). CHCHD2 and CHCHD10 mutations caused neurodegeneration in model animals as seen in patients, but their pathophysiological roles remain elusive. Here we reported a direct role of CHCHD2 and CHCHD10 in autophagy. We identified a protein complex composing of CHCHD2-CHCHD10-C1QBP/p32-Atg8-family proteins (ATG8s), in which each molecule interacted with another. CHCHD2, CHCHD10 and C1QBP/p32 associated with ATG8s, preferentially, GABARAPs. Disease-associated CHCHD2 and CHCHD10 mutations exhibited varied interaction with ATG8s. By binding to GABARAPs, CHCHD2 and CHCHD10 underwent autophagic degradation, and recruited the ULK1 complex. Autophagy initiation defects occurred upon transient knockdown of CHCHD2, and also in human iPSC-derived CHCHD2^-/- or CHCHD2^T61I dopaminergic neurons. Importantly, CHCHD2 and CHCHD10 promoted autophagy. CHCHD2 reduced protein aggregates in cells and toxic SNCA/α-synuclein species in mouse striatum. Our study thus revealed mitochondrial proteins CHCHD2 and CHCHD10 as both autophagy substrates and autophagy activators and laid groundwork for therapy targeting patients with neurodegeneration.