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:Mitochondrial diseases are a group of rare inherited disorders that affect mitochondrial function. A severe untreatable form of mitochondrial disease is Leigh syndrome (LS), which is characterized by psychomotor regression and acute metabolic crises during which patients quickly deteriorate. To accelerate drug discovery for mitochondrial diseases, we focused on drug repurposing and used induced pluripotent stem cell (iPSC)-derived neuronal precursor cells (NPCs) from LS patients to screen a library of 5,632 repurposable compounds. We identified phosphodiesterase 5 inhibitors (PDE5i) as leads capable of normalizing mitochondrial polarization in NPCs of LS patients. Among the PDE5i, we prioritized Sildenafil due to its established safety profile in children and adults. Sildenafil restored key pathways regulating nervous system development, enhanced neurite outgrowth in LS neurons, and mitigated abnormal calcium responses in LS brain organoids under metabolic stress. Chronic off-label compassionate treatment of six LS patients with Sildenafil showed good tolerability and clear clinical improvements. Our findings highlight the potential of iPSC-driven drug discovery for rare diseases and position Sildenafil as a promising drug candidate for patients with mitochondrial diseases.
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:THLE-2 cells were treated with 0 μM or 15 μM alectinib for 24 hours. Using data-independent acquisition (DIA) technology, a comprehensive analysis of phosphorylated proteins in human liver cells was performed.