Project description:Alzheimer’s disease (AD) is a chronic neurodegenerative disease needing effective therapeutics urgently. Sildenafil, one of the approved phosphodiesterase-5 inhibitors, has been implicated as having potential beneficial effect in AD. We showed that sildenafil usage is associated with reduced likelihood of AD across four new drug compactor cohorts, including bumetanide, furosemide, spironolactone, and nifedipine. For instance, sildenafil usage is associated with a 54% reduced prevalence of AD in MarketScan® (hazard ratio [HR] = 0.46, 95% CI 0.32-0.66) and a 30% reduced prevalence of AD in Clinformatics® (HR = 0.70, 95% CI 0.49-1.00) compared to spironolactone. We found that sildenafil treatment significantly reduced tau hyper-phosphorylation (pTau181, pTau205) in a dose-dependent manner in both familial and sporadic AD patient derived neurons. Further RNA-seq data analysis of sildenafil-treated AD patient iPSC-derived neurons revealed that sildenafil specifically targeting AD related genes and molecular pathways involved in axon guidance, AD-presenilin, neurogenesis, neurodegeneration, synaptic dysregulation, vascular smooth muscle contraction (VSMC) and cyclic guanosine monophosphate (cGMP)-protein kinase G (PKG) signaling pathway, mechanistically supporting the potential beneficial effect of sildenafil in AD. These real-world patient data validation and mechanistic observations from patient iPSC-derived neurons further suggested that sildenafil is a potential repurposable drug for AD. However, randomized clinical trials are required to validate sildenafil as a potential treatment of AD.
Project description:Differential expression in the presence and absence of sildenafil following romidepsin We performed cDNA microarray analysis using an GeneChip® Human Gene 2.0 ST Array to identify cellular genes that may be differentially expressed in the presence and absence of sildenafil following romidepsin treatment in SNK6
Project description:Recently, it is reported that sildenafil suppresses maturation of PO-induced miRNAs. However, the mechanism of how sildenafil coupled NO-cGMP-PKG signaling affects this maturation was not unraveled. Here, we show that PERK-mediated suppression of miRNAs by sildenafil is vital to keep mitochondrial homeostasis, using cardiac-specific PERK knockout (cko) mice.
Project description:Drug toxicity screening on retina is essential for the development of safe therapies for a large number of diseases, whilst preserving visual acuity and function. To this end, retinal organoids derived from human pluripotent stem cells (hPSCs) provide a suitable screening platform due to their similarity to human retina and the ease of generation in large-scale formats, offering almost unlimited excess of tissue. Two hPSC cell lines were differrentiated to retinal organoids which comprised all key retinal cell types in multiple nuclear and synaptic layers, enabling the maintenance of retinal ganglion and bipolar cells and moreover allowed the development of subtypes as revealed by the single cell RNA-Seq analysis. Ketorolac, Digoxin, Thioridazine, Sildenafil, Ethanol and Methanol were used to screen drug effects on retinal organoids. Exposure of the hPSC-derived retinal organoids to Diogxin, Thioridazine and Sildenafil exposure resulted in photoreceptor cell death, while Digoxin and Thioridazine additionally affected all other cell types, including Müller glia cells. Ethanol and Methanol caused an upregulation in retinal ganglion cell related geneexpression. All drug treatments activated astrocytes, indicated by dendrites sprouting into neuroepithelium and upregulation of astrocyte related genes. The ability to resond to light was presereved in organoids although the number of active retinal ganglion cells decreased after drug expsoure. These data indicate comparable drug effects in organoids to those reported in in vitro models and/or in humans, thus providing first robust experimental evidence of their suitability for toxicological studies.
Project description:Critical shortage of donor organs for treating end-stage organ failure highlights the urgent need for generating organs from induced pluripotent stem cells (hiPSCs). Despite many reports describing functional cell differentiation, no studies have succeeded in generating a three-dimensional vascularised organ such as liver. Here, we show the generation of vascularised and functional human liver from hiPSCs by transplantation of liver buds created in vitro (hiPSC-LBs). Specified hepatic cells self-organised into three-dimensional hiPSC-LBs by recapitulating organogenetic interactions between endothelial and mesenchymal cells. Immunostaining and gene expression analyses revealed resemblance between in vitro grown hiPSC-LBs and in vivo liver buds. Human vasculatures in hiPSC-LB transplants became functional by connecting to the host vessels within 48 hours. The formation of functional vasculatures stimulated the maturation of hiPSC-LBs into tissue resembling the adult liver. Highly metabolic hiPSC-derived tissue performed liver-specific functions such as protein production and human-specific drug metabolism without recipient liver replacement.