lncR-GAS5 upregulates the splicing factor SRSF10 to impair endothelial autophagy, leading to atherogenesis / 医学前沿

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.

Bioinformatics Analysis and Preliminary Functional Study of Abnormal Expression of Splicing Factors in Gastric Cancer / 中国医学科学院学报

To analyze the expression of splicing factors in gastric cancer using bioinformatics methods and investigate the effect of aberrantly expressed serine/arginine-rich splicing factor(SRSF10)on the phenotype of gastric cancer cells. The RNA-seq data of gastric cancer and paracancerous tissues were downloaded from The Cancer Genome Atlas(TCGA)cancer database,and bioinformatics analysis was performed to obtain the splicing factors differentially expressed in gastric cancer.The splicing factor SRSF10 was selected to investigate its effect on the development of gastric cancer.RNA interference technology was used to construct SRSF10 knockdown gastric cancer cells.MTS,Transwell,and cell scratches were used to study the effect of SRSF10 knockdown on gastric cancer cell phenotype. A total of 48 splicing factors were identified in gastric cancer by a series of bioinformatics techniques,of which 35 were up-regulated and 13 were down-regulated.The splicing factor SRSF10,which was up-regulated,was selected for further study.It was found that the gastric cancer cells after SRSF10 knockdown proliferated more slowly and had lower migration ability than normal gastric cancer cells. Multiple splicing factors are found in gastric cancer and may play an important role in the development of gastric cancer.The splicing factor SRSF10 may contribute to the pathogenesis of gastric cancer.

Antisense transcription regulates the expression of sense gene via alternative polyadenylation

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.

Research progress on genes associated with transformation of myelodysplastic syndromes to acute myeloid leukemia / 中国实验血液学杂志

Myelodysplastic syndrome (MDS) is highly heterogeneous clonal hematological malignancy, having a high rate of progression to acute myeloid leukemia (AML). With the rapid development of molecular biological techniques, plenty of gene mutations were found to have close relationships with the transformation from MDS to AML. SRSF2 is a RNA splicing-related gene, which mutation may prompt a poor prognosis, and have a higher rate of progressing to AML. DNMT3A plays an important role in DNA methylation, its mutation often indicate a worse overall survival and a more rapid progression to AML. ASXL1 regulates the synthesis of histone, which frameshift mutations are molecular marks of an adverse outcome. IDH contains IDH1 and IDH2, which are related with the Krebs cycle. Patients with IDH1 mutation have a shorter overall survival and a higher risk of AML transformation than that of patients with wild-type IDH1, while IDH2 was a poor prognostic factor for overall survival in patients with lower-risk MDS. Another gene related with DNA methylation is TET2, which is the most frequently mutated gene in MDS known so far and it may act as tumor-suppressor gene, but the opinions on its impact on patients' outcomes are still controversial. Some studies show that its mutations relate to a shorter time to progression to AML. Because of the differentiations in patients' races, regions and clinical characteristics, the results of different studies are varied. In this review, the recent advances on these related genes are summarized.

Clinical manifestation of the SRSF2 gene mutation in Chinese patients with chronic myelomonocytic leukemia / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Spliceosome mutations have been recently identified and associated with hematological malignancies. SRSF2, one of components of the splicing machinery, has a high mutation frequency during chronic myelomonocytic leukemia, according to previous reports. However, the relevance of this finding in Chinese populations remains unknown.</p><p><b>METHODS</b>We recruited 50 Chinese patients with chronic myelomonocytic leukemia to analyze the state of SRSF2 and to assess the corresponding clinical features by polymerase chain reaction followed by direct sequencing.</p><p><b>RESULTS</b>Ten of 50 patients (20%) harbored SRSF2 mutations, including five P95R, two 95H, and three P95L point mutations. The patient group was older than the wild type group (P < 0.01). No significant statistical differences were observed with regard to the other clinical characteristics (sex, peripheral blood count, serum lactate dehydrogenase, karyotype, World Health Organization classification, etc.) between these two groups. Two of the patients showed an early evolution to acute myeloid leukemia.</p><p><b>CONCLUSIONS</b>SRSF2 mutations are frequent in chronic myelomonocytic leukemia patients, but show a relatively lower incidence in Chinese patients. Moreover, the mutation can be related to old age and an unfavorable prognosis. Our results provide valuable insights for the development of a diagnostic marker, or for the identification of a therapeutic target for chronic myelomonocytic leukemia.</p>

Isolation and expression profiling of transformer 2 gene in Aedes aegypti / 南方医科大学学报

<p><b>OBJECTIVE</b>To isolate, identify and analyze the sex-determining gene Transformer 2 (Aaetra2) of the major vector mosquito Aedes aegypti.</p><p><b>METHODS</b>tBLASTn program, RT-PCR and RACE methods were used to obtain the full-length cDNA of Aaetra2. Multiple alignments of nucleotide and amino acid sequences were conducted, and the different domains in tra2 protein were indentified. RT-PCR of the total RNA extracted from different tissue from the mosquitoes in different developmental stages was performed using specific primers.</p><p><b>RESULTS</b>Two genes, namely Aaetra2-α and Aaetra2-β, were identified in different supercontig locations. The multi-transcripts were expressed by means of alternative promoters or terminators. The different domains in tra2 protein were defined as RS-rich N-terminal region, RNA recognition motif-RRM, linker region, and RS-rich C-terminal region. Both Aaetra2-α and Aaetra2-β showed sustained expression throughout the developmental stages of Ae.aegypti, and in all the tissues without a sex specificity.</p><p><b>CONCLUSION</b>Aaetra2 gene has multiple isoforms and is mapped to multiple locations in the genome. Aaetra2 has conservative functional domains of the sex-determining gene tra2. For Ae.agypti, Aaetra2 shows the potential as a new target for release of insects carrying a dominant lethal (RIDL) technology based on transgenic mosquitoes.</p>

SRSF2 mutation in patients with chronic myelomonocytic leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate SRSF2 mutations in patients with chronic myelomonocytic leukemia (CMML) and the clinical characteristics of patients with SRSF2 mutants.</p><p><b>METHODS</b>In this study, the frequency of SRSF2 mutation in a cohort of 20 patients with CMML was detected by polymerase chain reaction (PCR) followed by direct sequencing to couple with their clinical features.</p><p><b>RESULTS</b>Of 20 patients, 4 patients were found harboring SRSF2 mutations, including 2 P95L, 1 P95H and 1 P95R point mutations. There were no significantly statistical differences in terms of their clinical characteristics between mutant and wild type group.</p><p><b>CONCLUSION</b>SRSF2 mutation was not frequently occurred in CMML patients and might associated with poor prognosis. It might be a practically diagnostic maker and therapeutic target in CMML.</p>

Metoprolol attenuates pressure overload-induced myocardial hypertrophy through modulating Dryk1A-ASF-CaMKIIδ signaling pathways / 中华心血管病杂志

<p><b>OBJECTIVE</b>Previous study showed that the signaling pathway of dual-specificity tyrosine-phosphorylated and regulated kinase 1A (Dyrk1A)-alternative splicing factor (ASF)- alternative splicing of Ca(2+)/calmodulin-dependent protein kinase IIδ (CaMKIIδ) is related to myocardial hypertrophy. The aim of present study was to determine the effect and related mechamism of metoprolol on pressure overload induced myocardial hypertrophy.</p><p><b>METHODS</b>Pressure overload-induced hypertension was induced by coarctation of suprarenal abdominal aorta in rats. Rats were randomly divided into sham-operated control, hypertension and hypertension plus metoprolol (30 mg×kg(-1)×d(-1)) groups (n = 10 each). Blood pressure, the left ventricular weight to body weight ratio and cardiomyocytes area were measured, the protein expression of Dyrk1A and ASF were determined by Western blot and mRNA expression of alternative splicing of CaMKIIδ was detected by RT-PCR.</p><p><b>RESULTS</b>Four weeks after coarctation, cardiac hypertrophy was evidenced in rats of hypertensive group, and the protein expression of Dyrk1A was significantly upregulated, while the expression of ASF was significantly downregulated, the mRNA expression of CaMKIIδ A and B were significantly upregulated and mRNA expression of CaMKIIδ C was significantly downregulated compared to those in sham-operated control rats (all P < 0.05). Treatment with metoprolol effectively attenuated cardiac hypertrophy and reversed pressure overload induced changes on Dyrk1A and ASF, and alternative splicing of CaMKIIδ (all P < 0.05).</p><p><b>CONCLUSION</b>Metoprolol attenuates pressure overload-induced cardiac hypertrophy possibly through modulating Dryk1A-ASF-CaMKIIδ signaling pathways.</p>

Expression of neural salient serine-/arginine-rich protein 1 (NSSR1) in colorectal cancer / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the expression of neural salient serine/arginine-rich protein 1 (NSSR1) in colorectal cancer.</p><p><b>METHODS</b>RT-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.</p><p><b>RESULTS</b>NSSR1 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.</p><p><b>CONCLUSION</b>The extensive expression of NSSR1 in colorectal cancer cells may hint it's roles in the biological function of colorectal cancer.</p>

The class A macrophage scavenger receptor type I (SR-AI) recognizes complement iC3b and mediates NF-κB activation

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.