Long noncoding RNAs (lncRNAs) play a critical role in the regulation of atherosclerosis. Here, we investigated the role of the lncRNA growth arrest-specific 5 (lncR-GAS5) in atherogenesis. We found that the enforced expression of lncR-GAS5 contributed to the development of atherosclerosis, which presented as increased plaque size and reduced collagen content. Moreover, impaired autophagy was observed, as shown by a decreased LC3II/LC3I protein ratio and an elevated P62 level in lncR-GAS5-overexpressing human aortic endothelial cells. By contrast, lncR-GAS5 knockdown promoted autophagy. Moreover, serine/arginine-rich splicing factor 10 (SRSF10) knockdown increased the LC3II/LC3I ratio and decreased the P62 level, thus enhancing the formation of autophagic vacuoles, autolysosomes, and autophagosomes. Mechanistically, lncR-GAS5 regulated the downstream splicing factor SRSF10 to impair autophagy in the endothelium, which was reversed by the knockdown of SRSF10. Further results revealed that overexpression of the lncR-GAS5-targeted gene miR-193-5p promoted autophagy and autophagic vacuole accumulation by repressing its direct target gene, SRSF10. Notably, miR-193-5p overexpression decreased plaque size and increased collagen content. Altogether, these findings demonstrate that lncR-GAS5 partially contributes to atherogenesis and plaque instability by impairing endothelial autophagy. In conclusion, lncR-GAS5 overexpression arrested endothelial autophagy through the miR-193-5p/SRSF10 signaling pathway. Thus, miR-193-5p/SRSF10 may serve as a novel treatment target for atherosclerosis.
Humans ; Atherosclerosis/genetics* ; Autophagy/genetics* ; Cell Cycle Proteins/metabolism* ; Endothelial Cells/metabolism* ; Endothelium/metabolism* ; MicroRNAs/metabolism* ; Repressor Proteins/metabolism* ; RNA Splicing Factors ; Serine-Arginine Splicing Factors/genetics* ; RNA, Long Noncoding/metabolism*

Serine/arginine-rich splicing factor 7 (SRSF7), a known splicing factor, has been revealed to play oncogenic roles in multiple cancers. However, the mechanisms underlying its oncogenic roles have not been well addressed. Here, based on N⁶-methyladenosine (m⁶A) co-methylation network analysis across diverse cell lines, we find that the gene expression of SRSF7 is positively correlated with glioblastoma (GBM) cell-specific m⁶A methylation. We then indicate that SRSF7 is a novel m⁶A regulator, which specifically facilitates the m⁶A methylation near its binding sites on the mRNAs involved in cell proliferation and migration, through recruiting the methyltransferase complex. Moreover, SRSF7 promotes the proliferation and migration of GBM cells largely dependent on the presence of the m⁶A methyltransferase. The two m⁶A sites on the mRNA for PDZ-binding kinase (PBK) are regulated by SRSF7 and partially mediate the effects of SRSF7 in GBM cells through recognition by insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2). Together, our discovery reveals a novel role of SRSF7 in regulating m⁶A and validates the presence and functional importance of temporal- and spatial-specific regulation of m⁶A mediated by RNA-binding proteins (RBPs).
Humans ; Cell Line, Tumor ; Cell Proliferation ; Gene Expression Regulation, Neoplastic ; Glioblastoma/genetics* ; Methyltransferases/metabolism* ; RNA Splicing Factors/metabolism* ; RNA, Messenger/genetics* ; RNA-Binding Proteins/metabolism* ; Serine-Arginine Splicing Factors/metabolism* ; RNA Methylation/genetics*

Natural antisense transcripts (NAT) and alternative polyadenylation (APA) of messenger RNA (mRNA) are important contributors of transcriptome complexity, each playing a critical role in multiple biological processes. However, whether they have crosstalk and function collaboratively is unclear. We discovered that APA enriched in human sense-antisense (S-AS) gene pairs, and finally focused on RNASEH2C-KAT5 S-AS pair for further study. In cis but not in trans over-expression of the antisense KAT5 gene promoted the usage of distal polyA (pA) site in sense gene RNASEH2C, which generated longer 3' untranslated region (3'UTR) and produced less protein, accompanying with slowed cell growth. Mechanistically, elevated Pol II occupancy coupled with SRSF3 could explain the higher usage of distal pA site. Finally, NAT-mediated downregulation of sense gene's protein level in RNASEH2C-KAT5 pair was specific for human rather than mouse, which lacks the distal pA site of RNASEH2C. We provided the first evidence to support that certain gene affected phenotype may not by the protein of its own, but by affecting the expression of its overlapped gene through APA, implying an unexpected view for understanding the link between genotype and phenotype.
Cell Proliferation ; genetics ; Evolution, Molecular ; Gene Expression Regulation ; genetics ; HEK293 Cells ; Humans ; Polyadenylation ; genetics ; RNA, Antisense ; genetics ; RNA, Messenger ; genetics ; Ribonuclease H ; genetics ; Serine-Arginine Splicing Factors ; metabolism ; Transcription, Genetic ; Up-Regulation ; genetics

OBJECTIVETo investigate the expression of neural salient serine/arginine-rich protein 1 (NSSR1) in colorectal cancer.

METHODSRT-PCR, Western blot and immunohistochemical staining were used to detect the expression of NSSR1 mRNA and protein in different mouse tissues and human colorectal cancer, respectively.

RESULTSNSSR1 mRNA was expressed in mouse cerebrum, cerebellum, heart, liver, intestine, kidney and lung tissue, but NSSR1 protein was only expressed in neural tissues. In normal human intestinal mucosa, NSSR1 was expressed in the colorectal epithelial cells. In colorectal cancer, NSSR1 was highly expressed in the nucleus of tumor cells.

CONCLUSIONThe extensive expression of NSSR1 in colorectal cancer cells may hint it's roles in the biological function of colorectal cancer.

Animals ; Cell Cycle Proteins ; genetics ; metabolism ; Colon ; metabolism ; Colorectal Neoplasms ; metabolism ; Humans ; Mice ; Neoplasm Proteins ; genetics ; metabolism ; RNA, Messenger ; genetics ; RNA-Binding Proteins ; genetics ; metabolism ; Rectum ; metabolism ; Repressor Proteins ; genetics ; metabolism ; Serine-Arginine Splicing Factors

The macrophage scavenger receptor SR-AI binds to host tissue debris to perform clearance and it binds to bacteria for phagocytosis. In addition, SR-AI modulates macrophage activation through cell signaling. However, investigation of SR-AI signaling on macrophages is complicated due to its promiscuous ligand specificity that overlaps with other macrophage receptors. Therefore, we expressed SR-AI on HEK 293T cells to investigate its ligand binding and signaling. On 293Tcells, SR-AI could respond to E. coli DH5α, leading to NF-κB activation and IL-8 production. However, this requires E. coli DH5α to be sensitized by fresh serum that is treated with heat-inactivation or complement C3 depletion. Anti-C3 antibody inhibits the binding of SR-AI to serum-sensitized DH5α and blocks DH5α stimulation of SR-AI signaling. Further analysis showed that SR-AI can directly bind to purified iC3b but not C3 or C3b. By mutagenesis, The SRCR domain of SR-AI was found to be essential in SR-AI binding to serum-sensitized DH5α. These results revealed a novel property of SR-AI as a complement receptor for iC3b-opsonized bacteria that can elicit cell signaling.
Amino Acid Sequence ; Carrier Proteins ; genetics ; metabolism ; Complement C3b ; metabolism ; Escherichia coli ; immunology ; HEK293 Cells ; Humans ; Macrophage Activation ; Molecular Sequence Data ; Mutagenesis ; NF-kappa B ; genetics ; metabolism ; Phagocytosis ; Serine-Arginine Splicing Factors ; Signal Transduction