Browsing by Author "Li, Hui"

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Absence of correlation between chimeric RNA and aging
(MDPI AG, 2017) Huang, Reyna; Kumar, Shailesh; Li, Hui
Chimeric RNAs have been recognized as a phenomenon not unique to cancer cells. They also exist in normal physiology. Aging is often characterized by deregulation of molecular and cellular mechanisms, including loss of heterochromatin, increased transcriptional noise, less tight control on alternative splicing, and more stress-induced changes. It is thus assumed that chimeric RNAs are more abundant in older people. In this study, we conducted a preliminary investigation to identify any chimeric RNAs with age-based trends in their expression levels in blood samples. A chimeric RNA candidate list generated by bioinformatic analysis indicated the possibility of both negative and positive trends in the expression of chimeric RNAs. Out of this candidate list, five novel chimeric RNAs were successfully amplified in multiple blood samples and then sequenced. Although primary smaller sample sizes displayed some weak trends with respect to age, analysis of quantitative PCR data from larger sample sizes showed essentially no relationship between expression levels and age. Altogether, these results indicate that, contradictory to the common assumption, chimeric RNAs as a group are not all higher in older individuals and that placing chimeric RNAs in the context of aging will be a much more complex task than initially anticipated.
The landscape and implications of chimeric RNAs in cervical cancer
(Elsevier B.V., 2018) Wu, Peng; Yang, Shuo; Singh, Sandeep; Qin, Fujun; Kumar, Shailesh; Wang, Ling; Ma, Ding; Li, Hui
Background: Gene fusions and fusion products have been proven to be ideal biomarkers and drug targets for cancer. Even though a comprehensive study of cervical cancer has been conducted as part of the Cancer Genome Atlas (TCGA) project, few recurrent gene fusions have been found, and none above 3% of frequency. Methods: We believe that chimeric fusion RNAs generated by intergenic splicing represent a new repertoire of biomarkers and/or therapeutic targets. However, they would be missed when only genome sequences and fusions at DNA level are considered. We performed extensive data mining for chimeric RNAs using both our and TCGA cervical cancer RNA-Seq datasets. Multiple criteria were applied. We analyzed the landscape of chimeric RNAs at various levels, and from different angles. Findings: The chimeric RNA landscape changed as different filters were applied. 15 highly frequent (N10%) chimeric RNAs were identified. LHX6-NDUFA8 was detected exclusively in cervical cancer tissues and Pap smears, but not in normal controls. Mechanistically, it is not due to interstitial deletion, but a product of cis-splicing between adjacent genes. Silencing of another recurrent chimera, SLC2A11-MIF, resulted in cell cycle arrest and reduced cellular proliferation. This effect is unique to the chimera, and not shared by the two parental genes. Interpretation: Highly frequent chimeric RNAs are present in cervical cancers. They can be formed by intergenic splicing. Some have clear implications as potential biomarkers, or for shedding new light on the biology of the disease. Fund: Stand Up To Cancer and the National Science Foundation of China
The landscape of chimeric RNAs in non-diseased tissues and cells
(Oxford University Press, 2020) Singh, Sandeep; Qin, Fujun; Kumar, Shailesh; Elfman, Justin; Lin, Emily; Pham, Lam-Phong; Yang, Amy; Li, Hui
Chimeric RNAs and their encoded proteins have been traditionally viewed as unique features of neoplasia, and have been used as biomarkers and therapeutic targets for multiple cancers. Recent studies have demonstrated that chimeric RNAs also exist in non-cancerous cells and tissues, although large-scale, genome-wide studies of chimeric RNAs in non-diseased tissues have been scarce. Here, we explored the landscape of chimeric RNAs in 9495 non-diseased human tissue samples of 53 different tissues from the GTEx project. Further, we established means for classifying chimeric RNAs, and observed enrichment for particular classifications as more stringent filters are applied. We experimentally validated a subset of chimeric RNAs from each classification and demonstrated functional relevance of two chimeric RNAs in non-cancerous cells. Importantly, our list of chimeric RNAs in non-diseased tissues overlaps with some entries in several cancer fusion databases, raising concerns for some annotations. The data from this study provides a large repository of chimeric RNAs present in non-diseased tissues, which can be used as a control dataset to facilitate the identification of true cancer-specific chimeras.
UBA1-CDK16: A female-specific chimeric RNA emerging through evolution and involved in immune regulation
(American Association for the Advancement of Science, 2026) Shi, Xinrui; Blackburn, Loryn; Singh, Sandeep; Glowczyk-Gluc, Martyna; Tajammal, Anam; Zahra, Shafaque; Kumar, Shailesh; Cornelison, Robert; Liang, Chen; Qin, Fujun; Liu, Aiqun; Lin, Shitong; Tang, Yue; Elfman, Justin; Manley, Thomas; Bullock, Timothy; Haverstick, Doris M.; Wu, Peng; Li, Hui
Chimeric RNAs resulting from intergenic splicing represent a distinct mechanism for transcriptome expansion. To explore the role of this previously unidentified layer of the transcriptome in sex-specific immunity, we analyzed RNA sequencing data from 425 blood samples and identified a female-specific chimeric RNA, UBA1-CDK16, which was further validated in more than 1200 blood samples. This chimeric RNA forms via cis-splicing between two adjacent X-linked parental genes, UBA1 and CDK16, despite both being expressed in both sexes. We demonstrated that a female-specific chromatin loop at the UBA1-CDK16 junction sites facilitates the intergenic splicing. Evolutionary analysis revealed that UBA1-CDK16 became female specific in humans through at least two independent paths. Functional studies suggested that UBA1-CDK16 is enriched in the myeloid lineage and may regulate myeloid cell development. Notably, its abnormal expression in female patients with COVID-19 correlates with altered neutrophil counts, highlighting its potential role in the disease progression.