Project description:We identified a rare C5 gene variant in individuals with a history of Neisseria meningitis, suggesting a complement deficiency as a predisposing factor.
Project description:RNA polyadenylation is a key post-transcriptional modification essential for gene expression regulation. However, the role and mechanism of polyadenylation and its key molecule, polyadenylate binding protein nuclear 1 (PABPN1), in hepatocellular carcinoma (HCC) remain poorly understood. This study investigates the role of PABPN1 and its regulatory genes in HCC progression to identify potential therapeutic targets. Analysis of The Cancer Genome Atlas (TCGA) dataset and an independent HCC cohort revealed significant upregulation of PABPN1 in HCC patients, which correlates with poor prognosis. Loss-of-function studies using HCC cell lines and conditional knockout mouse models demonstrated that targeting PABPN1 inhibited HCC progression. Conversely, overexpression of PABPN1 promoted HCC development in vitro and in a hydrodynamic transfection hepatocarcinogenesis mouse model. Mechanistic investigations showed that PABPN1 modulates C5 mRNA polyadenylation and stability, with the PABPN1-C5 axis driving NF-kB activation and recruiting polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) to promote HCC progression. Therapeutic targeting of the PABPN1-C5 axis using the C5a receptor inhibitor CCX168 significantly inhibited HCC progression in both in vitro and in vivo models. This study identifies PABPN1 as a critical regulator of HCC development and sheds light on the post-transcriptional regulation of complement components in cancer. Targeting the PABPN1-C5 axis represents a promising strategy for HCC treatment.
Project description:Loss-of-function of the chromatin remodeler CHD7 causes CHARGE syndrome, characterized by variable penetrance and diverse abnormalities. However, establishing genotype-phenotype correlations has been challenging, as most CHD7 inactivating mutations are null alleles. Through CHD7 missense variant analysis at potential phosphorylation sites, we identified T730 (T720 in mice) as a critical residue associated with pathogenesis. Using a CHD7 T730 missense mutation (Chd7T720A) and a frameshift null allele (Chd7fs) in a mouse model, we found that Chd7fs/fs mice were non-viable, while Chd7fs/+ mice exhibited haploinsufficiency-related circling behavior. Notably, Chd7fs/T720A mice died before postnatal day 2, indicating the Chd7T720A allele is hypomorphic. Micro-CT analysis at E18.5 revealed heterozygous mice primarily exhibited hypertrophic cardiomyopathy (HCM), while homozygous mice developed both HCM and dilated cardiomyopathy (DCM). RNA-seq analysis of neonatal Chd7T720A/T720A hearts revealed a disrupted transcriptome, which in males and females was characterized by downregulation of mitochondrial energy metabolism genes and enrichment of ETS family transcription factor targets. We further identified GSK3β, GSK3α, HIPK1, and DYRK2 as candidate kinases for this site, suggesting a regulatory role in CHD7. This missense mutation causing developmental heart abnormalities establishes the first genotype-phenotype correlation for CHD7, and offers new insights into CHARGE syndrome pathogenesis.