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Some studies suggest that the inactivation of the Ras-MAPK pathway in trophoblast cells can lead to recurrent abortion, but the molecular mechanism underlying the inactivation of this pathway in trophoblast cells is still unclear. This study aimed to explore the relationship between the mechanism of abnormal activation of RASA1, a regulatory protein of the Ras-MAPK pathway, and unexplained recurrent spontaneous abortion. RT-qPCR was used to detect the transcription levels of RASA1 gene. Immunohistochemistry and Western blot were used to detect the expression levels of the RASA1, Raf and MEK proteins. CCK-8, TUNEL and Transwell assays were used to detect the proliferative, apoptotic, and invasive capacities of HTR-8/SVneo cells. ChIP assays were used to detect the enrichment of H3K27me3 in RASA1 gene promoter. Abortion villi experiments showed that the enrichment of H3K27me3 in the RASA1 gene promoter was reduced, and that both RASA1 gene transcription and RASA1 protein expression were increased. Cell experiments confirmed that RASA1 could decrease the phosphorylated Raf and MEK proteins, inhibit the proliferation and invasion ability, and promote the apoptosis ability of HTR-8/SVneo cells. It was also found that the proliferation and invasion ability as well as the Ras-MAPK pathway activity of HTR-8/SVneo cells were inhibited when treated with histone methyltransferase inhibitor DZNep. RASA1 gene was abnormally activated in unexplained recurrent spontaneous abortion villi due to the decreased enrichment of H3K27me3 in the gene promoter. High expression of RASA1 could inhibit the activity of the Ras-MAPK pathway, and thus inhibit the proliferation and invasion ability of trophoblast cells., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

Signal transduction has been reported to be involved in antidepressant treatment outcomes; however, its mechanisms remain unclear. The aims of this study were to explore the associations between antidepressant remission and single nucleotide polymorphisms (SNPs), haplotypes, and gene-gene interactions in the Ras-Raf-MAPK intracellular signaling pathway. A total of 302 inpatients with major depressive disorder (DSM-IV Axis I) were assessed using the 17-item Hamilton Depression Rating Scale before and after 8 weeks of antidepressant treatment to determine the remission rate in the samples. Twenty-four SNPs at five kinase genes (Ras-Raf-MEK-ERK-RSK), which are a part of the Ras-Raf-MAPK signaling pathway, were identified to investigate a genetic association with antidepressant drug outcome. Correlations between 24 SNPs at the five kinase genes in the Ras-Raf-MAPK signaling pathway and antidepressant drug outcome were not found. The percentage of the CCAGA haplotype that RSK(2/3/4)-RSKL(1/2) gene loci SNPs constructed was markedly lower in the remitter group when compared with the nonremitter group in female depressed patients (P=0.04), whereas the proportion of AAAGGG haplotype that RSK(2/3/4)-RSKL(1/2) gene loci SNPs constructed in the remitter group was significantly greater than that in the nonremitter group in male patients (P=0.02). In addition, MEK1 (rs28730804) and RSK3 (rs2229712) in the Ras-Raf-MAPK signaling pathway showed a gene-gene interaction that affected antidepressant drug outcome in female depressed patients (P=0.041). Although this study did not find that SNPs at the five kinase genes in the Ras-Raf-MAPK signaling pathway are important markers for antidepressant outcome, certain haplotypes that SNPs at the RSK(2/3/4)-RSKL(1/2) gene constructed may be important markers for antidepressant drug efficacy. We observed a gene-gene interaction in this signaling pathway that influenced antidepressant efficacy in female depressed patients. Therefore, it is likely that in female depressed patients, different haplotypes and gene-gene interaction in the Ras-Raf-MAPK signaling pathway are involved in mediating the pharmacological action of an antidepressant, and eventually influence antidepressant efficacy.

The methylation status, mutation and expression of RASSF1A, and mutations of RAS and BRAF were studied in 52 patients with multiple myeloma (MM), one plasma cell leukaemia (PCL) patient and four MM-derived cell lines. Aberrant methylation of RASSF1A was found in nine of 32 MM patients and in one of four MM cell lines (U266), where the associated loss of transcription was reversible by demethylation treatment. RASSF1A transcription was further investigated on anti-CD138-sorted plasma cell-enriched bone marrow samples from 10 MM, one PCL and three reactive plasmacytosis patients. While the wild-type RASSF1A transcript was detected in all three reactive plasmacytosis and the PCL samples, we found no detectable wild-type transcripts in six of 10 MM samples studied. In two MM samples, only the non-functional variant transcript was detected, whereas the other four showed loss of transcription. In great contrast to western data, RAS mutations were identified in only four of 31 (13%) MM patients. While no RASSF1A or BRAF mutation (V599E) was detected in any of the primary MM studied (n = 21), the latter was found in the U266 cell line. Taken together, these data indicate that alterations of RAS signalling are critical in MM pathogenesis. In our current studies of Chinese MM patients, these alterations involved frequent RASSF1A inactivation (60%) as a result of transcriptional silencing or expression of a non-functional variant transcript.