Importance Elevated low-density lipoprotein cholesterol (LDL-C) is a modifiable risk factor for cardiovascular disease, the leading cause of premature death worldwide. Assessing the LDL-C–related burden is critical for guiding prevention and treatment strategies. Objectives To estimate the global, regional, and national burden of ischemic heart disease and ischemic stroke attributable to elevated LDL-C (relative to 35-54 mg/dL) from 1990 to 2023 and to quantify the contributions of population growth, aging, risk-deleted burden, and exposure changes to burden trends. Design, Setting, and Population This comparative risk assessment, part of the Global Burden of Disease Study 2023, estimated population-level LDL-C exposure and associated health loss in 204 countries and territories. Mean LDL-C levels were estimated using spatiotemporal gaussian process regression based on 806 studies across 161 countries. Relative risks were derived from meta-analyses of 38 randomized clinical trials. Population-attributable fractions for deaths and disability-adjusted life-years (DALYs) were estimated by age and sex for adults aged 25 years or older from 1990 to 2023, with 95% uncertainty intervals. Exposure Population-level LDL-C concentrations. Main Outcomes and Measures Population-attributable fractions, counts, and rates (all ages and age standardized per 100 000) of LDL-C–attributable deaths and DALYs from ischemic heart disease and ischemic stroke, with uncertainty intervals. Results In 2023, elevated LDL-C accounted for 3.6 million deaths (95% uncertainty interval, 2.2-5.4 million; 6.0% of global mortality) and 90.7 million DALYs (95% uncertainty interval, 58.9-123.3 million; 3.2% of DALYs). Although global all-ages rates remained stable, age-standardized death and DALY rates decreased by 45.6% and 39.5%, respectively, since 1990. In 2023, age-standardized LDL-C–attributable DALY rates were highest in Eastern Europe and lowest in high-income Asia-Pacific. One-third of the global LDL-C burden occurred in India and China. Population growth and aging drove the increasing burden, with notable regional disparities in LDL-C exposure and risk-deleted DALY rates shifting toward middle-sociodemographic settings. Conclusions and Relevance Despite declining age-standardized rates, the absolute LDL-C burden has increased since 1990 due to demographic changes and has shifted toward middle-sociodemographic countries. Measurement and surveillance gaps persist. Strengthened prevention, diagnosis, and treatment access strategies are essential to mitigate the health burden of LDL-C.
Dysregulated Spliceosome Activity Involves Increased Intron Retention Plus Upregulation and Phosphorylation of SF3B1 in Chronic Lymphocytic Leukemia
Abstract BackgroundAlternative splicing (AS) is a fundamental process in eukaryotes contributing to the diversity of mRNA isoforms with variable ratios of intron/exon. SF3B1 is a pivotal protein of the spliceosome machinery. Mutations in the SF3B1 gene have prognostic value in Chronic Lymphocytic Leukemia (CLL). Our previous studies have shown that SF3B1 inhibition with macrolides induces apoptosis specifically in CLL compared with normal cells. SF3B1 inhibition is associated with a widespread increase in intron retention (IR) on most transcripts, suggesting that IR can be used as a marker of spliceosome inhibition in CLL cells. However, it is unknown how the activity of SF3B1 contributes to the spliceosome activity and the poor clinical prognosis in CLL.MethodsTo better understand this process, we performed a comprehensive analysis to quantify the abundance of individual exonic and intronic mapped reads on annotated RNA-Seq transcripts derived from the B cells of 98 CLL patients and nine healthy volunteers (Normal B cells – NBC). We calculated ratios for intron and exon abundance for each transcript and use this as a measure of intron retention (IR) and a surrogate for alternative splicing (AS).ResultsWe found that 66% of CLL B-cells transcripts had significant IR elevation compared to NBC and that transcripts with high IR were associated with low expression levels and mRNA downregulation. The IR increase in CLL B-cells was independent of prognostic factors such as IgVH or SF3B1 mutations. Transcripts with the highest IR levels belonged to biological pathways associated with gene expression and RNA splicing. Also, we observed a >2-fold increase of active pSF3B1 in CLL B-cells compared to NBC. Additionally, when the CLL-B cells were treated with macrolides (pladienolide-B), a significant decrease in pSF3B1, but not total SF3B1 protein was observed. ConclusionsOur findings suggest that IR/ARS is increased in CLL and that this process is associated with SF3B1 phosphorylation and susceptibility to SF3B1 inhibitors. These data provide additional support to the relevance of AS in carcinogenesis and evidence of pSF3B1 participation in this process.
Modulation of RNA splicing associated with Wnt signaling pathway using FD-895 and pladienolide B
Abstract BackgroundAlterations in RNA splicing are associated with different malignancies including leukemia, lymphoma, and solid tumors. The RNA splicing modulators such as FD-895 and pladienolide B have been investigated in different malignancies to target/modulate spliceosome for therapeutic purpose. MethodsThe different cell lines were screened using RNA splicing modulator to test in vitro cytotoxicity as well as ability to modulate RNA splicing capability via induction of intron retention (using RT-PCR and qPCR) was assessed. The Cignal Finder Reporter Array was used to screen the HeLa cell line to know the pathway affected the most by the splice modulators. Further the candidates associated with the pathways were validated at protein levels using western blot assay and gene-gene interaction study were carried out using GeneMANIA.ResultsWe show that FD-895 and pladienolide B have more apoptotic activities than conventional chemotherapy in different solid tumors. We found FD-895 or pladienolide B modulate Wnt signaling pathways and mRNA splicing. We showed that FD-895 or pladienolide B significantly down regulates not only Wnt signaling pathway-associated transcripts (GSK3β and LRP5), but also both transcript and proteins including LEF1, CCND1, LRP6, and pLRP6. ConclusionThese results indicate FD-895 and pladienolide B inhibit Wnt signaling by impeding with phosphorylation of LRP6 and modulates mRNA splicing through induction of intron retention in cervical cancer cells.