Trisomy 21-driven metabolite alterations are linked to cellular injuries in Down syndrome.

Down syndrome (DS) arises from a genetic anomaly characterized by an extra copy of chromosome 21 (exCh21). Despite high incidence of congenital diseases among DS patients, direct impacts of exCh21 remain elusive. Here, we established a robust DS model harnessing human-induced pluripotent stem cells (hiPSCs) from mosaic DS patient. These hiPSC lines encompassed both those with standard karyotype and those carrying an extra copy of exCh21, allowing to generate isogenic cell lines with a consistent genetic background. We unraveled that exCh21 inflicted disruption upon the cellular transcriptome, ushering in alterations in metabolic processes and triggering DNA damage. The impact of exCh21 was also manifested in profound modifications in chromatin accessibility patterns. Moreover, we identified two signature metabolites, 5-oxo-ETE and Calcitriol, whose biosynthesis is affected by exCh21. Notably, supplementation with 5-oxo-ETE promoted DNA damage, in stark contrast to the protective effect elicited by Calcitriol against such damage. We also found that exCh21 disrupted cardiogenesis, and that this impairment could be mitigated through supplementation with Calcitriol. Specifically, the deleterious effects of 5-oxo-ETE unfolded in the form of DNA damage induction and the repression of cardiogenesis. On the other hand, Calcitriol emerged as a potent activator of its nuclear receptor VDR, fostering amplified binding to chromatin and subsequent facilitation of gene transcription. Our findings provide a comprehensive understanding of exCh21's metabolic implications within the context of Down syndrome, offering potential avenues for therapeutic interventions for Down syndrome treatment.

Global gene expression analysis using RNA-seq reveals the new roles of Panax notoginseng Saponins in ischemic cardiomyocytes.

ETHNOPHARMACOLOGICAL RELEVANCE: Panax notoginseng saponins (PNS), the main active ingredients of Panax notoginseng (Burkill) F.H.Chen, have been clinically used for cardiovascular diseases treatment in China as the Traditional Chinese Medicine (TCM) (Duan et al., 2017). Evidence demonstrated that PNS protected cardiomyocytes from myocardial ischemia, but the more underlying molecular mechanisms of the protective effect are still unclear. The aims of this study are to systematically know the function of PNS and discover new roles of PNS in ischemic cardiomyocytes. MATERIALS AND METHODS: To confirm PNS function on ischemic cardiomyopathy, we established in vitro myocardial ischemia model on H9C2 cardiomyocyte line, which was induced by oxygen-glucose depletion (OGD). Then RNA-seq was carried out to systematically analyze global gene expression. This study was aimed to systematically investigate the protective effect and more potential molecular mechanisms of PNS on H9C2 cardiomyocytes in vitro through whole-transcriptome analysis with total RNA sequencing (RNA-Seq). RESULTS: PNS exhibited anti-apoptotic effect in H9C2 cardiomyocytes in OGD-induced myocardial ischemia model. Through RNA-seq, we found that OGD affected expression profiling of many genes, including upregulated and downregulated genes. PNS inhibited cardiomyocyte apoptosis and death through rescuing cell cycle arrest, the DNA double-strand breakage repair process and chromosome segregation. Interestingly, for the canonical signaling pathways regulation, RNA-seq showed PNS could inhibit cardiac hypertrophy, MAPK signaling pathway, and re-activate PI3K/AKT and AMPK signaling pathways. Experimental data also confirmed the PNS could protect cardiomyocytes from OGD-induced apoptosis through activating PI3K/AKT and AMPK signaling pathways. Moreover, RNA-seq demonstrated that the expression levels of many non-coding RNAs, such as miRNAs and lncRNAs, were significantly affected after PNS treatment, suggesting that PNS could protect cardiomyocytes through regulating non-coding RNAs. CONCLUSION: RNA-seq systematically revealed different novel roles of Panax Notoginseng Saponins (PNS) in protecting cardiomyocytes from apoptosis, induced by myocardial ischemia, through rescuing cell cycle arrest and cardiac hypertrophy, re-activating the DNA double-strand breakage repair process, chromosome segregation, PI3K/Akt and AMPK signaling pathways and regulating non-coding RNAs.

Panax notoginseng saponins inhibit ischemia-induced apoptosis by activating PI3K/Akt pathway in cardiomyocytes.

AIM OF THIS STUDY: The panax notoginseng saponins (PNS) have been clinically used for the treatment of cardiovascular diseases and stroke in China. Evidences demonstrated that PNS could protect cardiomyocytes from injury induced by ischemia, but the underlying molecular mechanisms of this protective effect are still unclear. This study was aimed to investigate the protective effect and potential molecular mechanisms of PNS on apoptosis in H9c2 cells in vitro and rat myocardial ischemia injury model in vivo. MATERIALS AND METHODS: H9c2 cells subjected to serum, glucose and oxygen deprivation (SGOD) were used as in vitro models and SD rats subjected to left anterior descending (LAD) coronary artery ligation were used as in vivo models. The anti-apoptotic effect of PNS was evaluated by Annexin V/PI analysis or TUNEL assay. Mitochondrial membrane potential (Δψm) was detected by JC-1 analysis. The expression of Akt and phosphorylated Akt (p-Akt) were detected by western blot assay. RESULTS: PNS exhibited anti-apoptotic effect both in H9c2 cells and in ischemic myocardial tissues. However, the effect was blocked in vitro by LY294002, a specific PI3K inhibitor. The anti-apoptotic effect of PNS was mediated by stabilizing Δψm in H9c2 cells. Furthermore the indices of the left ventricular ejection fractions (EF), left ventricular fractional shortening (FS), left ventricular dimensions at end diastole (LVDd) and left ventricular dimensions at end systole (LVDs) suggested that PNS improved rats cardiac function. PNS significantly increased p-Akt both in H9c2 cells and in ischemic myocardial tissues and this effect was also blocked by LY294002 in H9c2 cells. CONCLUSION: Results of this study suggested that PNS could protect myocardial cells from apoptosis induced by ischemia in both the in vitro and in vivo models through activating PI3K/Akt signaling pathway.