7 research outputs found
Changes in Ocular Surface Characteristics after Switching from Benzalkonium Chloride-Preserved Latanoprost to Preservative-Free Tafluprost or Benzalkonium Chloride-Preserved Tafluprost
Purpose. The aim of the present study was to examine the effects of switching from Latanoprost ophthalmic solution containing a preservative to preservative-free Tafluprost ophthalmic solution or Tafluprost containing a preservative on ocular surfaces. Materials and Methods. Forty patients (40 eyes) with glaucoma (mean age: 62.0 ± 10.9 years) using Latanoprost with preservative for six months or longer were assigned either to a Tafluprost-containing-preservative group (20 eyes) or preservative-free-Tafluprost group (20 eyes). The intraocular pressure, corneal epithelial barrier function (fluorescein uptake concentration with fluorophotometer FL-500), superficial punctate keratopathy (AD classification), and tear film breakup time (TBUT) were assessed before switching and at 12 weeks after switching. Results. No significant differences in intraocular pressure were noted after switching in either group. Corneal epithelial barrier function was improved significantly after switching in both the Tafluprost-containing-preservative and the preservative-free-Tafluprost groups. There were no significant differences in AD scores after switching in the Tafluprost-containing-preservative group, but significant improvements were noted in the preservative-free-Tafluprost group. No significant differences in TBUT were noted in the Tafluprost-containing-preservative or preservative-free-Tafluprost groups after switching. Conclusion. After switching from preservative Latanoprost to Tafluprost containing-preservative or preservative-free Tafluprost, corneal epithelial barrier function was improved while the intraocular pressure reduction was retained
Ras signaling directs endothelial specification of VEGFR2+ vascular progenitor cells
Vascular endothelial growth factor receptor 2 (VEGFR2) transmits signals of crucial importance to vasculogenesis, including proliferation, migration, and differentiation of vascular progenitor cells. Embryonic stem cell–derived VEGFR2+ mesodermal cells differentiate into mural lineage in the presence of platelet derived growth factor (PDGF)–BB or serum but into endothelial lineage in response to VEGF-A. We found that inhibition of H-Ras function by a farnesyltransferase inhibitor or a knockdown technique results in selective suppression of VEGF-A–induced endothelial specification. Experiments with ex vivo whole-embryo culture as well as analysis of H-ras−/− mice also supported this conclusion. Furthermore, expression of a constitutively active H-Ras[G12V] in VEGFR2+ progenitor cells resulted in endothelial differentiation through the extracellular signal-related kinase (Erk) pathway. Both VEGF-A and PDGF-BB activated Ras in VEGFR2+ progenitor cells 5 min after treatment. However, VEGF-A, but not PDGF-BB, activated Ras 6–9 h after treatment, preceding the induction of endothelial markers. VEGF-A thus activates temporally distinct Ras–Erk signaling to direct endothelial specification of VEGFR2+ vascular progenitor cells
Development of Orally Bioavailable Peptides Targeting an Intracellular Protein: From a Hit to a Clinical KRAS Inhibitor
Cyclic
peptides as a therapeutic modality are attracting
a lot
of attention due to their potential for oral absorption and accessibility
to intracellular tough targets. Here, starting with a drug-like hit
discovered using an mRNA display library, we describe a chemical optimization
that led to the orally available clinical compound known as LUNA18,
an 11-mer cyclic peptide inhibitor for the intracellular tough target
RAS. The key findings are as follows: (i) two peptide side chains
were identified that each increase RAS affinity over 10-fold; (ii)
physico-chemical properties (PCP) including Clog P can be adjusted by side-chain modification to increase
membrane permeability; (iii) restriction of cyclic peptide conformation
works effectively to adjust PCP and improve bio-activity; (iv) cellular
efficacy was observed in peptides with a permeability of around 0.4
× 10–6 cm/s or more in a Caco-2 permeability
assay; and (v) while keeping the cyclic peptide’s main-chain
conformation, we found one example where the RAS protein structure
was changed dramatically through induced-fit to our peptide side chain.
This study demonstrates how the chemical optimization of bio-active
peptides can be achieved without scaffold hopping, much like the processes
for small molecule drug discovery that are guided by Lipinski’s
rule of five. Our approach provides a versatile new strategy for generating
peptide drugs starting from drug-like hits