Mechanochemical and Conformational Study of N-heterocyclic Carbonyl-Oxime Transformations

New mechanochemical pathways for the transformation of six N-heterocyclic carbonyl compounds into oximes using hydroxylamine hydrochloride were explored. Reactions were performed first without any base since the heterocyclic moieties (imidazole, benzimidazole, pyridine and quinuclidine) have an intrinsic basic nitrogen atom. This green, solvent free method was suitable for all compounds (up to quantitative yields) except for N-benzyl substituted imidazole and benzimidazole-2-carbaldehyde. For the slower reacting aldehydes, reactions with liquid assisted grinding and addition of sodium hydroxide were performed as well. Conformational analysis and quantum-chemical calculations revealed steric and electronic reasons for the lower reactivity of N-benzyl substituted derivatives

Myeloid-related protein 8/14 complex describes microcirculatory alterations in patients with type 2 diabetes and nephropathy

<p>Abstract</p> <p>Background</p> <p>Inflammation contributes to cardiovascular complications in type 2 diabetes, which are often characterized by microvascular alterations. We investigated whether myeloid-related protein 8/14 complex (MRP8/14) secreted by transmigrating monocytes and granulocytes may represent a biomarker for microvascular alterations in patients with type 2 diabetes and nephropathy.</p> <p>Methods</p> <p>MRP8/14 was measured in 43 patients with type 2 diabetes and nephropathy. Additionally, the inflammatory markers Interleukin-6 (IL-6), Tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP) were quantified. To detect microvascular alterations proteinuria and retinal vessel caliber were used as classical and novel marker, respectively. Proteinuria was quantified by protein-creatinine ratio (PCR); retinal vessel caliber was quantified after retina photography on digitalized retina pictures.</p> <p>Results</p> <p>MRP8/14 was positively associated with inflammation (<it>r </it>= 0.57), proteinuria (<it>r </it>= 0.40) and retinal arterial caliber (<it>r </it>= 0.48). Type 2 diabetic patients with MRP8/14 values above the median of 5.8 μg/ml demonstrated higher proteinuria and larger retinal artery caliber than patients with MRP8/14 values below the median (logPCR: -0.51 ± 0.52 versus -0.96 ± 0.46, <it>P </it>< 0.01; retinal artery lumen (μm): 178.3 ± 14.1 versus 162.7 ± 14.9 <it>P </it>< 0.01). Both groups did not differ with regard to metabolic factors and blood pressure. MRP8/14 was an independent predictor of retinal artery caliber in multivariate stepwise regression analysis (<it>β </it>= 0.607) and was positively associated with IL-6 (<it>r </it>= 0.57, <it>P </it>< 0.001) and TNF-α (<it>r </it>= 0.36, <it>P </it>< 0.05).</p> <p>Conclusion</p> <p>MRP8/14 – a marker for transendothelial migration – describes not only the state of inflammation in diabetic nephropathy, but additionally the degree of microvascular alterations in the glomerular and retinal bed. Therefore, MRP8/14 may be a potentially selective novel biomarker for microcirculatory defects in diabetic nephropathy.</p

Visualizing alpha-synuclein and iron deposition in M83 mouse model of Parkinson’s disease in vivo

Abstract: Abnormal alpha-synuclein (αSyn) and iron accumulation in the brain play an important role in Parkinson's disease (PD). Herein, we aim to visualize αSyn inclusions and iron deposition in the brains of M83 (A53T) mouse models of PD in vivo. The fluorescent pyrimidoindole derivative THK-565 probe was characterized by means of recombinant fibrils and brains from 10- to 11-month-old M83 mice. Concurrent wide-field fluorescence and volumetric multispectral optoacoustic tomography (vMSOT) imaging were subsequently performed in vivo. Structural and susceptibility weighted imaging (SWI) magnetic resonance imaging (MRI) at 9.4 T as well as scanning transmission x-ray microscopy (STXM) were performed to characterize the iron deposits in the perfused brains. Immunofluorescence and Prussian blue staining were further performed on brain slices to validate the detection of αSyn inclusions and iron deposition. THK-565 showed increased fluorescence upon binding to recombinant αSyn fibrils and αSyn inclusions in post-mortem brain slices from patients with PD and M83 mice. Administration of THK-565 in M83 mice showed higher cerebral retention at 20 and 40 min post-intravenous injection by wide-field fluorescence compared to nontransgenic littermate mice, in congruence with the vMSOT findings. SWI/phase images and Prussian blue indicated the accumulation of iron deposits in the brains of M83 mice, presumably in the Fe3+ form, as evinced by the STXM results. In conclusion, we demonstrated in vivo mapping of αSyn by means of noninvasive epifluorescence and vMSOT imaging and validated the results by targeting the THK-565 label and SWI/STXM identification of iron deposits in M83 mouse brains ex vivo

Visualizing alpha-synuclein and iron deposition in M83 mouse model of Parkinson's disease in vivo

BACKGROUND Abnormal alpha-synuclein and iron accumulation in the brain play an important role in Parkinson's disease (PD). Herein, we aim at visualizing alpha-synuclein inclusions and iron deposition in the brains of M83 (A53T) mouse models of PD in vivo . METHODS Fluorescently labelled pyrimidoindole-derivative THK-565 was characterized by using recombinant fibrils and brains from 10-11 months old M83 mice, which subsequently underwent in vivo concurrent wide-field fluorescence and volumetric multispectral optoacoustic tomography (vMSOT) imaging. The in vivo results were verified against structural and susceptibility weighted imaging (SWI) magnetic resonance imaging (MRI) at 9.4 Tesla and scanning transmission X-ray microscopy (STXM) of perfused brains. Brain slice immunofluorescence and Prussian blue staining were further performed to validate the detection of alpha-synuclein inclusions and iron deposition in the brain, respectively. RESULTS THK-565 showed increased fluorescence upon binding to recombinant alpha-synuclein fibrils and alpha-synuclein inclusions in post-mortem brain slices from patients with Parkinson's disease and M83 mice. i.v. administration of THK-565 in M83 mice showed higher cerebral retention at 20 and 40 minutes post-injection by wide-field fluorescence compared to non-transgenic littermate mice, in congruence with the vMSOT findings. SWI/phase images and Prussian blue indicated the accumulation of iron deposits in the brains of M83 mice, presumably in the Fe $^{3+}$ form, as evinced by the STXM results. CONCLUSION We demonstrated in vivo mapping of alpha-synuclein by means of non-invasive epifluorescence and vMSOT imaging assisted with a targeted THK-565 label and SWI/STXM identification of iron deposits in M83 mouse brains ex vivo

Periodontal Ehlers-Danlos Syndrome Is Caused by Mutations in C1R and C1S, which Encode Subcomponents C1r and C1s of Complement

Periodontal Ehlers-Danlos syndrome (pEDS) is an autosomal-dominant disorder characterized by early-onset periodontitis leading to premature loss of teeth, joint hypermobility, and mild skin findings. A locus was mapped to an approximately 5.8 Mb region at 12p13.1 but no candidate gene was identified. In an international consortium we recruited 19 independent families comprising 107 individuals with pEDS to identify the locus, characterize the clinical details in those with defined genetic causes, and try to understand the physiological basis of the condition. In 17 of these families, we identified heterozygous missense or in-frame insertion/deletion mutations in C1R (15 families) or C1S (2 families), contiguous genes in the mapped locus that encode subunits C1r and C1s of the first component of the classical complement pathway. These two proteins form a heterotetramer that then combines with six C1q subunits. Pathogenic variants involve the subunit interfaces or inter-domain hinges of C1r and C1s and are associated with intracellular retention and mild endoplasmic reticulum enlargement. Clinical features of affected individuals in these families include rapidly progressing periodontitis with onset in the teens or childhood, a previously unrecognized lack of attached gingiva, pretibial hyperpigmentation, skin and vascular fragility, easy bruising, and variable musculoskeletal symptoms. Our findings open a connection between the inflammatory classical complement pathway and connective tissue homeostasis

Structural Basis of Proline-Proline Peptide Bond Specificity of the Metalloprotease Zmp1 Implicated in Motility of Clostridium difficile

Clostridium difficile is a pathogenic bacterium causing gastrointestinal diseases from mild diarrhea to toxic megacolon. In common with other pathogenic bacteria, C. difficile secretes proteins involved in adhesion, colonization, and dissemination. The recently identified Zmp1 is an extracellular metalloprotease showing a unique specificity for Pro-Pro peptide bonds. The endogenous substrates of Zmp1 are two surface proteins implicated in adhesion of C. difficile to surface proteins of human cells. Thus, Zmp1 is believed to be involved in the regulation of the adhesion-motility balance of C. difficile. Here, we report crystal structures of Zmp1 from C. difficile in its unbound and peptide-bound forms. The structure analysis revealed a fold similar to Bacillus anthracis lethal factor. Crystal structures in the open and closed conformation of the S-loop shed light on the mode of binding of the substrate, and reveal important residues for substrate recognition and the strict specificity of Zmp1 for Pro-Pro peptide bonds