Small molecule enhancers of rapamycin-induced TOR inhibition promote autophagy, reduce toxicity in Huntington's disease models and enhance killing of mycobacteria by macrophages

Upregulation of autophagy may have therapeutic benefit in a range of diseases that includes neurodegenerative conditions caused by intracytosolic aggregate-prone proteins, such as Huntington's disease, and certain infectious diseases, such as tuberculosis. The best-characterized drug that enhances autophagy is rapamycin, an inhibitor of the TOR (target of rapamycin) proteins, which are widely conserved from yeast to man. Unfortunately, the side effects of rapamycin, especially immunosuppression, preclude its use in treating certain diseases including tuberculosis, which accounts for approximately 2 million deaths worldwide each year, spurring interest in finding novel drugs that selectively enhance autophagy. We have recently reported a novel two-step screening process for the discovery of such compounds. We first identified compounds that enhance the growth-inhibitory effects of rapamycin in the budding yeast Saccharomyces cerevisiae, which we termed small molecule enhancers of rapamycin (SMERs). Next we showed that three SMERs induced autophagy independently, or downstream of mTOR, in mammalian cells, and furthermore enhanced the clearance of a mutant huntingtin fragment in Huntington's disease cell models. These SMERs also protected against mutant huntingtin fragment toxicity in Drosophila. We have subsequently tested two of the SMERs in models of tuberculosis and both enhance the killing of mycobacteria by primary human macrophages.     

A hypothesis on the identification of the editing enzyme in plant organelles

RNA editing in plant organelles is an enigmatic process leading to conversion of cytidines into uridines. Editing specificity is determined by proteins; both those known so far are pentatricopeptide repeat (PPR) proteins. The enzyme catalysing RNA editing in plants is still totally unknown. We propose that the DYW domain found in many higher plant PPR proteins is the missing catalytic domain. This hypothesis is based on two compelling observations: (i) the DYW domain contains invariant residues that match the active site of cytidine deaminases; (ii) the phylogenetic distribution of the DYW domain is strictly correlated with RNA editing.     

15N magnetic relaxation study of backbone dynamics of the ribosome-associated cold shock response protein Yfia of Escherichia coli

In the solution structure of the ribosome-associated cold shock response protein Yfia of Escherichia coli in the free state two structural segments can be distinguished: a well structured, rigid N-terminal part displaying a betaalphabetabetabetaalpha topology and a flexible C-terminal tail comprising last 20 amino-acid residues. The backbone dynamics of Yfia protein was studied by (15)N nuclear magnetic relaxation at three magnetic fields and analyzed using model-free approach. The overall diffusional tumbling of the N-terminal part is strongly anisotropic with a number of short stretches showing increased mobility either on a subnanosecond time scale, or a micro- to millisecond time scale, or both. In contrast, the unstructured polypeptide chain of the C-terminal part, which cannot be regarded as a rigid structure, shows the predominance of fast local motions over slower ones, both becoming faster closer to the C-terminus.     

Hypochlorous acid-mediated generation of glycerophosphocholine from unsaturated plasmalogen glycerophosphocholine lipids

The myeloperoxidase-derived metabolite hypochlorous acid (HOCl) promotes the selective cleavage of plasmalogens into chloro fatty aldehydes and 1-lysophosphatidylcholine (LPC). The subsequent conversion of the initially generated LPC was investigated in plasmalogen samples in dependence on the fatty acid residue in the sn-2 position by matrix-assisted laser desorption and ionization time-of-flight mass spectrometry and (31)P NMR spectroscopy. Plasmalogens containing an oleic acid residue in the sn-2 position are converted by moderate amounts of HOCl primarily to 1-lyso-2-oleoyl-sn-glycero-3-phosphocholine and at increased HOCl concentrations to the corresponding chlorohydrin species. In contrast, plasmalogens containing highly unsaturated docosahexaenoic acid yield upon HOCl treatment 1-lyso-2-docosahexaenoyl-glycerophosphocholine and glycerophosphocholine. The formation of the latter product denotes a novel pathway for the action of HOCl on plasmalogens.     

Intrahepatic Vascular Anatomy in Rats and Mice—Variations and Surgical Implications

Introduction

The intra-hepatic vascular anatomy in rodents, its variations and corresponding supplying and draining territories in respect to the lobar structure of the liver have not been described. We performed a detailed anatomical imaging study in rats and mice to allow for further refinement of experimental surgical approaches.

Methods

LEWIS-Rats and C57Bl/6N-Mice were subjected to ex-vivo imaging using μCT. The image data were used for semi-automated segmentation to extract the hepatic vascular tree as prerequisite for 3D visualization. The underlying vascular anatomy was reconstructed, analysed and used for determining hepatic vascular territories.

Results

The four major liver lobes have their own lobar portal supply and hepatic drainage territories. In contrast, the paracaval liver is supplied by various small branches from right and caudate portal veins and drains directly into the vena cava. Variations in hepatic vascular anatomy were observed in terms of branching pattern and distance of branches to each other. The portal vein anatomy is more variable than the hepatic vein anatomy. Surgically relevant variations were primarily observed in portal venous supply.

Conclusions

For the first time the key variations of intrahepatic vascular anatomy in mice and rats and their surgical implications were described. We showed that lobar borders of the liver do not always match vascular territorial borders. These findings are of importance for the design of new surgical procedures and for understanding eventual complications following hepatic surgery.     

Surface molecules on HaCaT keratinocytes after interaction with non‐thermal atmospheric pressure plasma

Non‐thermal atmospheric‐pressure plasmas have been developed that will be used in future for several purposes, e.g. medicine. Living tissues and cells are at the focus of plasma treatment, e.g. to improve wound healing, or induce apoptosis and growth arrest in tumour cells. Detailed investigations of plasma‐cell interactions are needed. Cell surface adhesion molecules as integrins, cadherins or the EGFR (epidermal growth factor receptor) are of importance in wound healing and also for development of cancer metastasis. This study has focused on measurement of cell surface molecules on human HaCaT keratinocytes (human adult low calcium temperature keratinocytes) promoting adhesion, migration and proliferation as one important feature of plasma‐cell interactions. HaCaT keratinocytes were treated with plasma by a surface dielectric barrier discharge in air. Cell surface molecules and induction of intracellular ROS (reactive oxygen species) were analysed by flow cytometry 24 h after plasma treatment. Besides a reduction of cell viability a significant down‐regulation of E‐cadherin and the EGFR expression occurred. The influence on α₂‐ and β₁‐integrins was less pronounced, and expression of ICAM‐1 (intercellular adhesion molecule 1) was unaffected. The extent of effects depended on the exposure time of cells to the plasma and the treatment regimen. Intracellular level of ROS detected by the fluorescent dye H₂DCFDA (2′,7′‐dichlorodihydrofluorescein diacetate) increased by plasma treatment, but it was neither dependent on the treatment time nor related to the different treatment regimens. Two‐dimensional cultures of HaCaT keratinocytes appear to be a suitable method of investigating plasma‐cell interactions.     

Comparative morphology of photoreceptors in free-living plathelminths — a survey

In free-living Plathelminthes, the best-known photoreceptors are pigment-cup ocelli, eyes formed of one or several pigmented supportive cells into whose cup-shaped cavity project the light-sensitive elements of one or several sensory cells. Besides these, so-called Sehkolben, photoreceptors lacking pigment granules, are found in some species. Sensory cells in plathelminth photoreceptors most commonly use microvilli as the light-sensitive organelles, but some use cilia and combinations of microvilli and cilia. Lamellate ciliary bodies with cilia whose membranes are strongly flattened and rolled and pericerebral ciliary aggregations with interwoven cilia protruding into an intracellular cavity are likely photoreceptors in that they show amplification of membrane likely to bear photoreceptive pigments. Cells with ballooned cilia and tubular vacuoles are other differentiations to which light-sensitivity has been attributed. A variety of structures serve as lenses, all usually formed from parts of the pigment cell.