Involvement of the splicing factor SART1 in the BRCA1-dependent homologous recombination repair of DNA double-strand breaks.

Although previous studies have reported that pre-mRNA splicing factors (SFs) are involved in the repair of DNA double-strand breaks (DSBs) via homologous recombination (HR), their exact role in promoting HR remains poorly understood. Here, we showed that SART1, an SF upregulated in several types of cancer, promotes DSB end resection, an essential first step of HR. The resection-promoting function of SART1 requires phosphorylation at threonine 430 and 695 by ATM/ATR. SART1 is recruited to DSB sites in a manner dependent on transcription and its RS domain. SART1 is epistatic with BRCA1, a major HR factor, in the promotion of resection, especially transcription-associated resection in the G2 phase. SART1 and BRCA1 accumulate at DSB sites in an interdependent manner, and epistatically counteract the resection blockade posed by 53BP1 and RIF1. Furthermore, chromosome analysis demonstrated that SART1 and BRCA1 epistatically suppressed genomic alterations caused by DSB misrepair in the G2 phase. Collectively, these results indicate that SART1 and BRCA1 cooperatively facilitate resection of DSBs arising in transcriptionally active genomic regions in the G2 phase, thereby promoting faithful repair by HR, and suppressing genome instability.

Efficient topical treatments of cutaneous lupus erythematosus: A systematic review and network meta-analysis.

OBJECTIVES: Although cutaneous lupus erythematosus (CLE) has been treated with topical agents, there was no high-quality evidence of which agents were more effective, and which clinical scores were more suitable. METHODS: On December 22nd, 2023, a search was conducted across five databases to identify randomized controlled trials (RCTs). Two authors independently screened the titles and abstracts of articles based on predetermined criteria. Selected articles were then assessed for inclusion in a blinded manner, with any disagreements resolved through consensus. Data were abstracted in duplicate, and a random-effects model was utilized for network meta-analysis. The certainty of the evidence was evaluated according to PRISMA guidelines, using the Grading of Recommendations Assessment, Development and Evaluation approach. The analysis was finalized in January 2024, with the primary outcome focused on the change in cutaneous lupus erythematosus disease area and severity index (CLASI) from baseline. RESULTS: Seven RCTs involving 231 participants were analyzed. The network meta-analysis (NMA) revealed that 4% nicotinamide demonstrated the highest probability of achieving the intended outcomes, with a mean difference (MD) of 3.10 and a 95% confidence interval (CI) of 1.99-4.21. Additionally, 0.05% clobetasol, 2% nicotinamide, and 0.1% tacrolimus also exhibited statistically significant differences, with MDs of 2.30 and 95% CIs of 0.73-3.88; 2.30 and 0.97-3.63; and 1.30 and 0.03-2.57, respectively. CONCLUSION: As data with a high level of evidence, NMAs demonstrated that 4% nicotinamide, 0.05% clobetasol, 2% nicotinamide, and 0.1% tacrolimus are statistically significant topical agents. CLASI may be an appropriate outcome to evaluate drug efficacy in CLE.

Single cell analysis in systemic sclerosis - A systematic review.

In recent years, rapid advances in research methods have made single cell analysis possible. Systemic sclerosis (SSc), a disease characterized by the triad of immune abnormalities, fibrosis, and vasculopathy, has also been the subject of various analyses. To summarize the results of single cell analysis in SSc accumulated to date and to deepen our understanding of SSc. Four databases were used to perform a database search on 23rd June 2023. Assessed Grading of Recommendations Assessment, Development and Evaluation certainty of evidence were performed according to PRISMA guidelines. The analysis was completed on July 2023. 17 studies with 358 SSc patients were included. Three studies used PBMCs, six used skin, nine used lung with SSc-interstitial lung diseases (ILDs), and one used lung with SSc-pulmonary arterial hypertension (PAH). The cells studied included immune cells such as T cells, natural killer cells, monocytes, macrophages, and dendritic cells, as well as endothelial cells, fibroblasts, keratinocytes, alveolar type I cells, basal epithelial cells, smooth muscle cells, mesothelial cells, etc. This systematic review revealed the results of single cell analysis, suggesting that PBMCs, skin, SSc-ILD, and SSc-PAH show activation and dysfunction of cells associated with immune-abnormalities, fibrosis, and vasculopathy, respectively.

Deregulated JNK signaling enhances apoptosis during hyperthermia.

PURPOSE: c-Jun N-terminal kinases (JNKs) comprise a subfamily of mitogen-activated protein kinases (MAPKs). The JNK group is known to be activated by a variety of stimuli. However, the molecular mechanism underlying heat-induced JNK activation is largely unknown. The aim of this study was to clarify how JNK activity is stimulated by heat. METHODS AND MATERIALS: The expression levels of various MAPK members in HeLa cells, with or without hyperthermia treatment, were evaluated via western blotting. The kinase activity of MAPK members was assessed through in vitro kinase assays. Cell death was assessed in the absence or presence of siRNAs targeting MAPK-related members. RESULTS: Hyperthermia decreased the levels of MAP3Ks, such as ASK1 and MLK3 which are JNK kinase kinase members, but not those of the downstream MAP2K/SEK1 and MAPK/JNK. Despite the reduced or transient phosphorylation of ASK1, MLK3, or SEK1, downstream JNK was phosphorylated in a temperature-dependent manner. In vitro kinase assays demonstrated that heat did not directly stimulate SEK1 or JNK. However, the expression levels of DUSP16, a JNK phosphatase, were decreased upon hyperthermia treatment. DUSP16 knockdown enhanced the heat-induced activation of ASK1-SEK1-JNK pathway and apoptosis. CONCLUSION: JNK was activated in a temperature-dependent manner despite reduced or transient phosphorylation of the upstream MAP3K and MAP2K. Hyperthermia-induced degradation of DUSP16 may induce activation of the ASK1-SEK1-JNK pathway and subsequent apoptosis.