Harnack inequality for fractional sub-Laplacians in Carnot groups

In this paper we prove an invariant Harnack inequality on Carnot-Carath\'eodory balls for fractional powers of sub-Laplacians in Carnot groups. The proof relies on an "abstract" formulation of a technique recently introduced by Caffarelli and Silvestre. In addition, we write explicitly the Poisson kernel for a class of degenerate subelliptic equations in product-type Carnot groups

N‒substituted 5‒hydroxy‒pyrrol‒2‒ones based cholecystokinin‒2 antagonists as experimental anticancer agents for the treatment of lung cancer

Background: Cholecystokinin and gastrin are endocrine growths factors for certain tumours and CCK1 R and CCK2R receptors are ideal molecular targets for novel smart chemo‒ therapeutics with a beneficial overall profile due to their anxiolytic and antidepressant properties. Lung cancers are fuelled by gastrin and therefore, selective gastrin (CCK2 R) antagonists are ideal experimental drug candidates. Objective: Synthesis and evaluation of novel CCK antagonists, most preferred CCK2 / gastrin selective for the treatment of lung cancers. Methods: A fast and efficient synthesis of hydroxy‒pyrrolones in 2 steps from renewable biomass was performed. After initial radiolabelled receptor binding studies with hot CCK8, subsequent in vitro evaluation with isolated duodenum preparations confirmed CCK antagonism. Cell based studies using the MTT assay provided a candidate for in vivo xenograft models with nude mice. Rational drug design was supported by molecular modelling experiments. Results: Potent and selective CCK antagonists were prepared as stable crystalline materials in high yields. Gastrin antagonists were in vitro active on isolated tissue preparations and inhibited breast, colon and lung cancer cell lines in vitro with IC50 to 45nM for the privileged hydroxyl‒pyrrolone lead structure in the MTT assay for human cancer cell lines. PNB‒101, a fluorinated 5‒hydroxy‒5‒aryl‒pyrrol‒2‒one, gave up to 80% inhibition of tumour growths by oral administration in athymic mice transplanted with the human lung cancer cell line H727. Conclusion: PNB‒101 is a potential chemotherapeutic agent for CCK‒gastrin related cancers and entered preclinical development

Validation of serum cytokines as potential biomarkers in acute dengue infection

Objectives: Serum IL-10, Macrophage inhibitory factor (MIF) and interferons have been found to be associated with fatal dengue. We set out to investigate the possibility of using these cytokine as biomarkers to predict severe dengue. Methods: Serum IL-10 levels were determined by quantitative ELISA in 215 adult patients with confirmed acute dengue infection (ADI). Serum IFNα and IFNγ levels were done in 79 patients. Serial recording of clinical features and laboratory investigations were done to determine clinical disease severity. Results: 33 (17.46%) patients were classified as severe dengue (SD). Serum IL-10 levels were significantly higher (p=0.0034) in patients with SD (median= 121.9, range= 24.98 to 3271 pg/ml) when compared to those with non SD (median= 78.28, range= 7.18 to 1343 pg/ml). In the 29 patients with paired serum samples, serum IL-10 levels rose in all 6 patients with SD whereas in 20/23 patients with non SD, serum IL-10 levels fell in the critical phase.  Although serum MIF values were higher in patients with SD (mean 70774, SD± 59874 pg/ml) when compared to those with non SD (mean 45362, SD± 26891 pg/ml), this was not statistically significant. The IFNγ levels were significantly higher (p=0.038) in patients with shock (median= 77.55, range= 18.21 to 468.4 pg/ml) when compared to those who did not develop shock (median= 35.25, range= 4.050 to 733.1 pg/ml). Conclusion: Serum IL-10 levels appear to be associated with SD. It would be crucial to investigate the possible role of this cytokine in the pathogenesis of SD

Structural basis for the RING catalyzed synthesis of K63 linked ubiquitin chains

This work was supported by grants from Cancer Research UK (C434/A13067), the Wellcome Trust (098391/Z/12/Z) and Biotechnology and Biological Sciences Research Council (BB/J016004/1).The RING E3 ligase catalysed formation of lysine 63 linked ubiquitin chains by the Ube2V2–Ubc13 E2 complex is required for many important biological processes. Here we report the structure of the RING domain dimer of rat RNF4 in complex with a human Ubc13~Ub conjugate and Ube2V2. The structure has captured Ube2V2 bound to the acceptor (priming) ubiquitin with Lys63 in a position that could lead to attack on the linkage between the donor (second) ubiquitin and Ubc13 that is held in the active “folded back” conformation by the RING domain of RNF4. The interfaces identified in the structure were verified by in vitro ubiquitination assays of site directed mutants. This represents the first view of the synthesis of Lys63 linked ubiquitin chains in which both substrate ubiquitin and ubiquitin-loaded E2 are juxtaposed to allow E3 ligase mediated catalysis.PostprintPeer reviewe

The impact of point mutations in the human androgen receptor : classification of mutations on the basis of transcriptional activity

Peer reviewedPublisher PD

Novel AroA from Pseudomonas putida Confers Tobacco Plant with High Tolerance to Glyphosate

Glyphosate is a non-selective broad-spectrum herbicide that inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS, also designated as AroA), a key enzyme in the aromatic amino acid biosynthesis pathway in microorganisms and plants. Previously, we reported that a novel AroA (PpAroA1) from Pseudomonas putida had high tolerance to glyphosate, with little homology to class I or class II glyphosate-tolerant AroA. In this study, the coding sequence of PpAroA1 was optimized for tobacco. For maturation of the enzyme in chloroplast, a chloroplast transit peptide coding sequence was fused in frame with the optimized aroA gene (PparoA1optimized) at the 5′ end. The PparoA1optimized gene was introduced into the tobacco (Nicotiana tabacum L. cv. W38) genome via Agrobacterium-mediated transformation. The transformed explants were first screened in shoot induction medium containing kanamycin. Then glyphosate tolerance was assayed in putative transgenic plants and its T1 progeny. Our results show that the PpAroA1 from Pseudomonas putida can efficiently confer tobacco plants with high glyphosate tolerance. Transgenic tobacco overexpressing the PparoA1optimized gene exhibit high tolerance to glyphosate, which suggest that the novel PpAroA1 is a new and good candidate applied in transgenic crops with glyphosate tolerance in future

RNAseq Analyses Identify Tumor Necrosis Factor-Mediated Inflammation as a Major Abnormality in ALS Spinal Cord

ALS is a rapidly progressive, devastating neurodegenerative illness of adults that produces disabling weakness and spasticity arising from death of lower and upper motor neurons. No meaningful therapies exist to slow ALS progression, and molecular insights into pathogenesis and progression are sorely needed. In that context, we used high-depth, next generation RNA sequencing (RNAseq, Illumina) to define gene network abnormalities in RNA samples depleted of rRNA and isolated from cervical spinal cord sections of 7 ALS and 8 CTL samples. We aligned \u3e50 million 2X150 bp paired-end sequences/sample to the hg19 human genome and applied three different algorithms (Cuffdiff2, DEseq2, EdgeR) for identification of differentially expressed genes (DEG’s). Ingenuity Pathways Analysis (IPA) and Weighted Gene Co-expression Network Analysis (WGCNA) identified inflammatory processes as significantly elevated in our ALS samples, with tumor necrosis factor (TNF) found to be a major pathway regulator (IPA) and TNFα-induced protein 2 (TNFAIP2) as a major network “hub” gene (WGCNA). Using the oPOSSUM algorithm, we analyzed transcription factors (TF) controlling expression of the nine DEG/hub genes in the ALS samples and identified TF’s involved in inflammation (NFkB, REL, NFkB1) and macrophage function (NR1H2::RXRA heterodimer). Transient expression in human iPSC-derived motor neurons of TNFAIP2 (also a DEG identified by all three algorithms) reduced cell viability and induced caspase 3/7 activation. Using high-density RNAseq, multiple algorithms for DEG identification, and an unsupervised gene co-expression network approach, we identified significant elevation of inflammatory processes in ALS spinal cord with TNF as a major regulatory molecule. Overexpression of the DEG TNFAIP2 in human motor neurons, the population most vulnerable to die in ALS, increased cell death and caspase 3/7 activation. We propose that therapies targeted to reduce inflammatory TNFα signaling may be helpful in ALS patients

Atomic structures of TDP-43 LCD segments and insights into reversible or pathogenic aggregation.

The normally soluble TAR DNA-binding protein 43 (TDP-43) is found aggregated both in reversible stress granules and in irreversible pathogenic amyloid. In TDP-43, the low-complexity domain (LCD) is believed to be involved in both types of aggregation. To uncover the structural origins of these two modes of β-sheet-rich aggregation, we have determined ten structures of segments of the LCD of human TDP-43. Six of these segments form steric zippers characteristic of the spines of pathogenic amyloid fibrils; four others form LARKS, the labile amyloid-like interactions characteristic of protein hydrogels and proteins found in membraneless organelles, including stress granules. Supporting a hypothetical pathway from reversible to irreversible amyloid aggregation, we found that familial ALS variants of TDP-43 convert LARKS to irreversible aggregates. Our structures suggest how TDP-43 adopts both reversible and irreversible β-sheet aggregates and the role of mutation in the possible transition of reversible to irreversible pathogenic aggregation

Poro-mechanical analysis of a biomimetic scaffold for osteochondral defects

Osteochondral defects are focal areas of damage involving articular cartilage and sub-chondral bone. Tissue engineering scaffolds are used to improve the organism regeneration ability for this kind of injury, serving as biocompatible structures for cell viability and differentiation. Since biomechanical cues such as substrate stiffness, loading conditions and fluid permeation are fundamental for successful tissue repair, understanding how these features vary in the scaffold is of primary importance. Here we present a mathematical model based on porous media mechanics for the analysis of a tissue engineering scaffold. We consider a three-layered scaffold mimicking a complete osteochondral tissue and vary the mechanical properties of the intermediate layer over a physiological range. Our results show that the interstitial fluid pressure and the vertical component of the solid effective stress depend significantly on the stiffness and permeability of the intermediate layer under mechanical loading. By properly tuning these material properties, regimes of slow or fast temporal variations of mechanical stress can be obtained in the scaffold layer of interest