Biology subjects

Shorrock, H. K.

Publications and source records attributed to Shorrock, H. K..

4 recordsLinked to original sources

bioRxiv2026

Inosine misincorporation into mRNA triggers the integrated stress response and activates an innate immune gene expression signature

The inosine triphosphate pyrophosphatase (ITPase) enzyme restricts levels of the non-canonical nucleotides (deoxy)inosine triphosphate (dITP/ITP) and prevents their aberrant misincorporation into nucleic acids. ITPase deficiency is associated with dilated cardiomyopathy and epileptic encephalopathy in humans and is usually fatal in infancy. It leads to pronounced inosine misincorporation into RNA but the cellular consequences of this misincorporation are not well understood and the pathogenic basis of ITPase deficiency remains unknown. Here we show that cellular transfection of mRNA with inosine misincorporation activates the integrated stress response (ISR) with an innate immune gene expression signature. This stress response triggers stress granule formation and is modulated by the double stranded RNA sensor protein Kinase R (PKR). Inosine nucleoside treatment of ITPase-deficient cells leads to endogenous inosine misincorporation into mRNA and activation of the ISR. Further, differentiation of human ITPase-deficient induced pluripotent stem cells into neurons results in a low-level stress response. Thus, our study establishes inosine misincorporation into mRNA as an unappreciated form of cellular stress. This is normally prevented by the ITPase enzyme, with implications for the pathogenesis of ITPase deficiency.

molecular biology↗

bioRxiv2025

The lncRNA PACER Regulates Lung Adenocarcinoma Phenotypes via COX-2 Signaling and RNA Structural Dynamics

Long noncoding RNAs (lncRNAs) are a class of regulatory RNAs with critical roles in cellular homeostasis and disease pathogenesis, including cancer. Dysregulated lncRNA expression in lung adenocarcinoma (LUAD) contributes to oncogenic mechanisms through immune and inflammatory signaling networks, including the arachidonic acid (AA) signaling pathway. Here, we investigate the functional significance of the lncRNA PACER (PTGS2 Antisense NF-{kappa}B1 Complex-Mediated Expression Regulator), which modulates cyclooxygenase-2 (COX-2), a key enzyme in the AA pathway. Using stable shRNA-mediated knockdown in A549 LUAD cells, we show that PACER silencing reduces COX-2 expression and impairs cellular proliferation, migration, and invasion. Bioinformatic analysis using LncLOOM revealed conserved motifs across primates and mice, including predicted binding sites for miR-18a-5p, miR-196-5p, miR-1306-5p, and miR-423-3p. To define PACERs structural organization, we performed selective 2'-hydroxyl acylation analyzed by primer extension and mutational profiling (SHAPE-MaP), generating the first secondary structure determination of PACER. SHAPE-MaP and SuperFold analyses revealed a compact, stabilized 5' domain and a flexible central and 3' region. {Delta}SHAPE analysis identified multiple sites of differential protection, and Rsample clustering resolved two dominant in vivo conformations, suggesting that PACER adopts a modular architecture with defined structural domains. These structured regions coincide with conserved motifs associated with NF-{kappa}B p50 and predicted miRNA binding sites, indicating that PACER function may depend on conformational switching that modulates protein and miRNA accessibility. Together, these findings establish PACER as a regulator of LUAD proliferation and invasion via COX-2 signaling and highlight its potential as a biomarker and therapeutic target in inflammatory cancers.

cancer biology↗

bioRxiv2024

CAG repeat-selective compounds reduce abundance of expanded CAG RNAs in patient cell and murine models of SCAs

Spinocerebellar ataxias (SCAs) are a genetically heterogenous group of devastating neurodegenerative conditions for which clinical care currently focuses on managing symptoms. Across these diseases there is an unmet need for therapies that address underlying disease mechanisms. We utilised the shared CAG repeat expansion mutation causative for a large subgroup of SCAs, to develop a novel disease-gene independent and mechanism agnostic small molecule screening approach to identify compounds with therapeutic potential across multiple SCAs. Using this approach, we identified the FDA approved microtubule inhibitor Colchicine and a novel CAG-repeat binding compound that reduce expression of disease associated transcripts across SCA1, 3 and 7 patient derived fibroblast lines and the Atxn1154Q/2Q SCA1 mouse model in a repeat selective manner. Furthermore, our lead candidate rescues dysregulated alternative splicing in Atxn1154Q/2Q mice. This work provides the first example of small molecules capable of targeting the underlying mechanism of disease across multiple CAG SCAs.

molecular biology↗

bioRxiv2021

CCG*CGG interruptions in high penetrance SCA8 families increase RAN translation and protein toxicity

Spinocerebellar ataxia type 8 (SCA8), a dominantly inherited neurodegenerative disorder caused by a CTG*CAG expansion, is unusual because most individuals that carry the mutation do not develop ataxia. To understand the variable penetrance of SCA8 we studied the molecular differences between highly penetrant families and more common sporadic cases (82%) using a large cohort of SCA8 families (N=77). We show that repeat expansion mutations from individuals with two or more affected family members have CCG*CGG interruptions at a higher frequency than sporadic SCA8 cases and that the number of CCG*CGG interruptions correlates with age at onset. At the molecular level, CCG*CGG interruptions increase RNA hairpin stability and steady state levels of SCA8 RAN polyAla and polySer proteins. Additionally, the CCG*CGG interruptions, which encode arginine interruptions in the polyGln frame increase the toxicity of the resulting proteins. In summary, CCG*CGG interruptions increase polyAla and polySer RAN protein levels, polyGln protein toxicity and disease penetrance and provide novel insight into the molecular differences between SCA8 families with high vs. low disease penetrance.

genetics↗