Partial monosomy14q involving FOXG1 and NOVA1 in an infant with microcephaly, seizures and severe developmental delay

NOVA1 acts on Impact to regulate hypothalamic function and translation in inhibitory neurons

We describe a patient haploinsufficient for the neuronal RNA binding protein NOVA1 who developed a behavioral motor hyperactivity disorder, suggesting a role of NOVA1 in postnatal motor inhibition. To investigate Nova1's action in adult Gad2+ inhibitory neurons, we generated a conditional Nova1-null mouse (Nova1-cKOGad2-cre). Strikingly, the phenotypes of these mice show many similarities to the NOVA1 haploinsufficient patient and identify a function of Nova1 in the hypothalamus. Molecularly, Nova1 loss in Gad2-positive neurons alters downstream expression of Impact mRNA, along with a subset of RNAs encoding electron transport chain-related factors and ribosomal proteins. NOVA1 stabilizes Impact mRNA by binding its 3' UTR, antagonizing the actions of miR-138 and miR-124. Together, these studies demonstrate actions of NOVA1 in adult hypothalamic neurons, mechanisms by which it functions in translation and metabolism, including through direct binding to Impact mRNA, and illuminate its role in human neurologic disease.

The RNA-binding protein RBM47 inhibits non-small cell lung carcinoma metastasis through modulation of AXIN1 mRNA stability and Wnt/β-catentin signaling

BACKGROUND

Non-small-cell lung cancer (NSCLC) remains a highly prevalent and deadly form of cancer, with efforts to better understand the molecular basis of the progression of this disease being essential to its effective treatment. Several recent studies have highlighted the ability of RNA-binding proteins (RBPs) to regulate a wide range of cellular processes in both healthy and pathogenic contexts. Among these RBPs, RNA binding motif protein 47 (RBM47) has recently been identified as a tumor suppressor in both breast and colon cancers, whereas its role in NSCLC is poorly understood.

METHODS

RBM47 expression in NSCLC samples was evaluated by RT-PCR, western blotting and immunohistochemistry analysis. Molecular and cellular techniques including lentiviral vector-mediated knockdown were used to elucidate the functions and mechanisms of RBM47.

RESULTS

This study sought to analyze the expression and role of RBM47 in NSCLC. In the present study, we observed reduced levels of RBM47 expression in NSCLC, with these reductions corresponding to a poorer prognosis and more advanced disease including a higher TNM stage (p = 0.022), a higher likelihood of tumor thrombus (p = 0.001), and pleural invasion (p = 0.033). Through functional analyses in vitro and in vivo, we further demonstrated that these RBP was able to disrupt the proliferation, migration, and invasion of NSCLC cells. At a molecular level, we determined that RBM47 was able to bind the AXIN1 mRNA, stabilizing it and thereby enhancing the consequent suppression of Wnt/β-catentin signaling.

CONCLUSION

Together our findings reveal that RBM47 targets AXIN1 in order to disrupt Wnt/β-catenin signaling in NSCLC and thereby disrupting tumor progression. These results thus offer new insights into the molecular biology of NSCLC, and suggest that RBM47 may also have value as a prognostic biomarker and/or therapeutic target in NSCLC patients.

The RNA binding protein neuro-oncological ventral antigen 1 (NOVA1) regulates IL-6 mRNA stability to enhance JAK2-STAT3 signaling in CRC

The molecular mechanisms governing the metastasis of colorectal cancer (CRC) are incompletely understood. In the present study, we found NOVA1 to be expressed at higher levels in CRC cell lines and tissue samples, and this upregulation was positively correlated with TNM stage (p = 0.034), poor differentiation (p = 0.001), and lymph node metastasis (p = 0.008). Both overall survival (OS) and relapse-free survival (RFS) were both significantly decreased in patients with high NOVA1 expression relative to those with low expression. Through a multivariate analysis, we determined that NOVA1 independently predicted poor outcomes in those with CRC. In further functional studies, we found that NOVA1 expression controlled the proliferation and invasive characteristics of CRC cells via a mechanism wherein NOVA1 bound and stabilized the IL6 mRNA, enhancing IL-6/JAK2/STAT3 signaling to in turn upregulate matrix metalloproteinases (MMPs) 2, 7, and 9. NOVA1 therefore plays key functional roles in regulating CRC progression, and our results further indicate that it serve as a valuable prognostic biomarker and potentially a target for therapeutic treatment in individuals with CRC.

Precisely controlling endogenous protein dosage in hPSCs and derivatives to model FOXG1 syndrome

Dosage of key regulators impinge on developmental disorders such as FOXG1 syndrome. Since neither knock-out nor knock-down strategy assures flexible and precise protein abundance control, to study hypomorphic or haploinsufficiency expression remains challenging. We develop a system in human pluripotent stem cells (hPSCs) using CRISPR/Cas9 and SMASh technology, with which we can target endogenous proteins for precise dosage control in hPSCs and at multiple stages of neural differentiation. We also reveal FOXG1 dose-dependently affect the cellular constitution of human brain, with 60% mildly affect GABAergic interneuron development while 30% thresholds the production of MGE derived neurons. Abnormal interneuron differentiation accounts for various neurological defects such as epilepsy or seizures, which stimulates future innovative cures of FOXG1 syndrome. By means of its robustness and easiness, dosage-control of proteins in hPSCs and their derivatives will update the understanding and treatment of additional diseases caused by abnormal protein dosage.

Altered dosage of developmental regulators such as transcription factors can result in disorders, such as FOXG1 syndrome. Here, the authors demonstrate the utility of SMASh technology for modulating protein dosage by modeling FOXG1 syndrome using human pluripotent stem cell-derived neurons and neural organoids.

NOVA1 acts as an oncogene in melanoma via regulating FOXO3a expression

Increasing studies have suggested that dysregulation of RNA‐binding proteins (RBPs) contributes to cancer progression. Neuro‐oncological ventral antigen 1 (NOVA1) is a novel RBP and plays an important role in tumour development. However, the expression and role of NOVA1 in melanoma remain unknown. In this study, we indicated that NOVA1 expression was up‐regulated in melanoma samples and cell lines. Moreover, we demonstrated that knockdown of NOVA1 suppressed melanoma cell proliferation, migration and invasion in both A375 and A875 cell lines. In addition, we showed that suppressed expression of NOVA1 enhanced forkhead box O3a (FOXO3a) expression while inhibited AKT expression in melanoma cell. Furthermore, we demonstrated that inhibited expression of FoxO3A rescued NOVA1‐mediated cell proliferation, migration and invasion in melanoma cell line A375. These results suggested that NOVA1 acted as an oncogene in the development of melanoma partly through regulating FoxO3A expression.

Neuro-oncological ventral antigen 1 (NOVA1): Implications in neurological diseases and cancers

Neuro-oncological ventral antigen 1 (NOVA1) is a RNA-binding protein that interacts with RNA containing repeats of the YCAY sequence. This protein is a brain-specific splicing factor regulating neuronal alternative splicing. It has been increasingly recognized as an important contributor to neurological disorders and carcinogenesis. In this review, we summarize the biological functions and pathological roles of NOVA1. The clinical implications of NOVA1 will also be discussed.