In Vitro Evaluation of Antimicrobial Activity of Minocycline Formulations for Topical Application in Periodontal Therapy.

Periodontal therapy using antimicrobials that are topically applied requires slow or controlled release devices. The in vitro antimicrobial activity of biodegradable polymer formulations that contain a new minocycline lipid complex (P-MLC) was evaluated. The new P-MLC formulations that contained 11.5% minocycline were compared with pure minocycline or an existing commercial formulation, which included determination of minimal inhibitory concentration (MIC) values against two oral bacteria and activity on six-species periodontal biofilm. Moreover, the flow of gingival crevicular fluid (GCF) was modeled up to 42 d and the obtained eluates were tested both for MIC values and inhibiting biofilm formation. In general, MICs of the P-MLC formulations were slightly increased as compared with pure minocycline. Biofilm formation was clearly inhibited by all tested formulations containing minocycline with no clear difference between them. In 3.5 d old biofilms, all formulations with 250 µg/mL minocycline decreased bacterial counts by 3 log10 and metabolic activity with no difference to pure antimicrobials. Eluates of experimental formulations showed superiority in antimicrobial activity. Eluates of one experimental formulation (P503-MLC) still inhibited biofilm formation at 28 d, with a reduction by 1.87 log10 colony forming units (CFU) vs. the untreated control. The new experimental formulations can easily be instilled in periodontal pockets and represent alternatives in local antimicrobials, and thus warrant further testing

Comparative profiling identifies C13orf3 as a component of the Ska complex required for mammalian cell division

Proliferation of mammalian cells requires the coordinated function of many proteins to accurately divide a cell into two daughter cells. Several RNAi screens have identified previously uncharacterised genes that are implicated in mammalian cell division. The molecular function for these genes needs to be investigated to place them into pathways. Phenotypic profiling is a useful method to assign putative functions to uncharacterised genes. Here, we show that the analysis of protein localisation is useful to refine a phenotypic profile. We show the utility of this approach by defining a function of the previously uncharacterised gene C13orf3 during cell division. C13orf3 localises to centrosomes, the mitotic spindle, kinetochores, spindle midzone, and the cleavage furrow during cell division and is specifically phosphorylated during mitosis. Furthermore, C13orf3 is required for centrosome integrity and anaphase onset. Depletion by RNAi leads to mitotic arrest in metaphase with an activation of the spindle assembly checkpoint and loss of sister chromatid cohesion. Proteomic analyses identify C13orf3 (Ska3) as a new component of the Ska complex and show a direct interaction with a regulatory subunit of the protein phosphatase PP2A. All together, these data identify C13orf3 as an important factor for metaphase to anaphase progression and highlight the potential of combined RNAi screening and protein localisation analyses

A Genome-Scale DNA Repair RNAi Screen Identifies SPG48 as a Novel Gene Associated with Hereditary Spastic Paraplegia

We have identified a novel gene in a genome-wide, double-strand break DNA repair RNAi screen and show that is involved in the neurological disease hereditary spastic paraplegia

MISSION esiRNA for RNAi Screening in Mammalian Cells

RNA interference (RNAi) is a basic cellular mechanism for the control of gene expression. RNAi is induced by short double-stranded RNAs also known as small interfering RNAs (siRNAs). The short double-stranded RNAs originate from longer double stranded precursors by the activity of Dicer, a protein of the RNase III family of endonucleases. The resulting fragments are components of the RNA-induced silencing complex (RISC), directing it to the cognate target mRNA. RISC cleaves the target mRNA thereby reducing the expression of the encoded protein1,2,3. RNAi has become a powerful and widely used experimental method for loss of gene function studies in mammalian cells utilizing small interfering RNAs

Synthesis and Structure-Activity Relationships of Pyrazole-based Inhibitors of Meprin α and β

Targeting metalloproteinases has been in focus of drug design for a long time. However, human proteinases of the astacin family, in particular meprin α and β emerged as potential drug targets just recently. More and more data links them to several diseases with different pathological background. Nevertheless, the validation of meprins as suitable drug targets requires highly potent and selective inhibitors as chemical probes to elucidate their role in pathophysiology. Albeit highly selective inhibitors of meprin β have already been reported, only inhibitors of meprin α with modest activity or selectivity are known. Starting from recently reported heteroaromatic scaffolds, the aim of this study was the optimization of meprin α and/or meprin β inhibition while keeping the favorable off-target inhibition profile over other metalloproteases. We now report novel potent pan-meprin inhibitors as well as highly active inhibitors of meprin α with superior selectivity over meprin β. The latter are suitable to serve as chemical probes and enable further target validation of meprin proteases

Extrudates of lipophilic tetracycline complexes: A new option for periodontitis therapy.

The objective of this study was to develop an improved drug delivery system for the local antimicrobial treatment of periodontitis, that offers enhanced drug stability, easy application and controlled release over several weeks. Chelate complexes consisting of a tetracycline antibiotic and a fatty acid salt were developed. Minocycline and doxycycline were paired with magnesium- and calcium stearate in different molar ratios. These chelate complexes stabilize the active pharmaceutical ingredient and enable the incorporation into a PLGA (poly(lactic-co-glycolic acid)) polymer matrix via hot melt extrusion. The chelate complexes were characterized via UV/Vis- and IR-spectroscopy. A high antibiotic activity of the complex was observed in a disc diffusion test. The drug complex was mixed with different PLGA-polymers and cryomilled in advance of the extrusion. The hot melt extrusion yielded homogeneous extrudates with a diameter from 600 to 900 µm. They contain 11.5% of minocycline, are adjustable in length and are easy to handle. In vitro release studies revealed a controlled release of the drug over 42 days. In conclusion, the developed extrudates are promising systems to improve the treatment of periodontitis

Synthesis and structure–activity relationships of pyrazole-based inhibitors of meprin α and β

AbstractTargeting metalloproteinases has been in the focus of drug design for a long time. However, meprin α and β emerged as potential drug targets just recently and are linked to several diseases with different pathological background. Nevertheless, the validation of meprins as suitable drug targets still requires highly potent and selective inhibitors as chemical probes to elucidate their role in pathophysiology. Albeit highly selective inhibitors of meprin β have already been reported, only inhibitors of meprin α with modest activity or selectivity are known. Starting from recently reported heteroaromatic scaffolds, the aim of this study was the optimisation of meprin α and/or meprin β inhibition while keeping the favourable off-target inhibition profile over other metalloproteases. We report potent pan-meprin inhibitors as well as highly active inhibitors of meprin α with superior selectivity over meprin β. The latter are suitable to serve as chemical probes and enable further target validation

Primary Evaluation of Potential Small Molecule Inhibitors of the Astacin Metalloproteinase Ovastacin, A Novel Drug Target in Female Infertility Treatment

Despite huge progress in hormonal therapy and improved in vitro fertilization methods, the success rates in infertility treatment are still limited. A recently discovered mechanism revealed the interplay between the plasma protein fetuin-B and the cortical granule-based proteinase ovastacin as novel key-mechanism in the regulation of fertilization. Upon sperm-egg fusion, cleavage of a distinct zona pellucida component by ovastacin destroys the sperm receptor, enhances zona robustness and eventually provides a definitive block against polyspermy. An untimely onset of this zona hardening prior to fertilization would consequently result in infertility. Physiologically, this process is controlled by fetuin-B, an endogenous ovastacin inhibitor. Here we aimed at the discovery of small molecular inhibitors of ovastacin that could mimic the effect of fetuin-B. Hence, these compounds could be useful lead structures for the development of specific ovastacin inhibitors that can be utilized in infertility treatment or in vitro fertilization.</p