Viral degradasome hijacks mitochondria to suppress innate immunity

The balance between the innate immunity of the host and the ability of a pathogen to evade it strongly influences pathogenesis and virulence. The two nonstructural (NS) proteins, NS1 and NS2, of respiratory syncytial virus (RSV) are critically required for RSV virulence. Together, they strongly suppress the type I interferon (IFN)-mediated innate immunity of the host cells by degrading or inhibiting multiple cellular factors required for either IFN induction or response pathways, including RIG-I, IRF3, IRF7, TBK1 and STAT2. Here, we provide evidence for the existence of a large and heterogeneous degradative complex assembled by the NS proteins, which we named “NS-degradasome” (NSD). The NSD is roughly ∼300-750 kD in size, and its degradative activity was enhanced by the addition of purified mitochondria in vitro. Inside the cell, the majority of the NS proteins and the substrates of the NSD translocated to the mitochondria upon RSV infection. Genetic and pharmacological evidence shows that optimal suppression of innate immunity requires mitochondrial MAVS and mitochondrial motility. Together, we propose a novel paradigm in which the mitochondria, known to be important for the innate immune activation of the host, are also important for viral suppression of the innate immunity.     

Neem Leaf Glycoprotein Prophylaxis Transduces Immune Dependent Stop Signal for Tumor Angiogenic Switch within Tumor Microenvironment

We have reported that prophylactic as well as therapeutic administration of neem leaf glycoprotein (NLGP) induces significant restriction of solid tumor growth in mice. Here, we investigate whether the effect of such pretreatment (25µg/mice; weekly, 4 times) benefits regulation of tumor angiogenesis, an obligate factor for tumor progression. We show that NLGP pretreatment results in vascular normalization in melanoma and carcinoma bearing mice along with downregulation of CD31, VEGF and VEGFR2. NLGP pretreatment facilitates profound infiltration of CD8⁺ T cells within tumor parenchyma, which subsequently regulates VEGF-VEGFR2 signaling in CD31⁺ vascular endothelial cells to prevent aberrant neovascularization. Pericyte stabilization, VEGF dependent inhibition of VEC proliferation and subsequent vascular normalization are also experienced. Studies in immune compromised mice confirmed that these vascular and intratumoral changes in angiogenic profile are dependent upon active adoptive immunity particularly those mediated by CD8⁺ T cells. Accumulated evidences suggest that NLGP regulated immunomodulation is active in tumor growth restriction and normalization of tumor angiogenesis as well, thereby, signifying its clinical translation.     

Nppb Neurons Are Sensors of Mast Cell-Induced Itch

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The attractiveness of odorous esterified fatty acids to the potential biocontrol agent,Altica cyanea

The fatty acid composition of foliar buds, young, mature, and senescent leaves, and stem parts of the rice-field weed, Ludwigia adscendens L. (Onagraceae) was analyzed by thin layer chromatography and gas chromatography flame ionization detection. The analysis of fatty acid composition revealed that saturated fatty acids (i.e., C14:0, C16:0, and C18:0) were prevailing compounds among the all weed parts except senescent leaves where C18:1 was predominant. The esterified fatty acids isolated from different weed parts over the range of 10–100 μg/ml followed by individual synthetic esterified fatty acids that were identified from the esterified extracts of different weed parts, and a mixture of synthetic esterified fatty acids except esterified eicosenoic acid and docosahexaenoic acid were applied to identify their role as a chemical cue for a potential biocontrol agent, Altica cyanea (Weber) (Coleoptera: Chrysomelidae) in a Y-tube olfactometer under laboratory conditions. In this bioassay, the esterified fatty acids from mature leaves and stem parts of this weed attracted A. cyanea at 20–100 μg/ml and at 80 μg/ml concentrations, respectively. Clear attraction was recorded by female A. cyanea insects in the mixture of synthetic esterified fatty acids at 60, 80, and 100 μg/ml concentrations. It is thus concluded that A. cyanea rely on an effective proportion of esterified fatty acids as an olfactory cue for attraction.     

PRMT1 methylates the single Argonaute of Toxoplasma gondii and is important for the recruitment of Tudor nuclease for target RNA cleavage by antisense guide RNA

Argonaute (Ago) plays a central role in RNA interference in metazoans, but its status in lower organisms remains ill-defined. We report on the Ago complex of the unicellular protozoan, Toxoplasma gondii (Tg), an obligatory pathogen of mammalian hosts. The PIWI-like domain of TgAgo lacked the canonical DDE/H catalytic triad, explaining its weak target RNA cleavage activity. However, TgAgo associated with a stronger RNA slicer, a Tudor staphylococcal nuclease (TSN), and with a protein Arg methyl transferase, PRMT1. Mutational analysis suggested that the N-terminal RGG-repeat domain of TgAgo was methylated by PRMT1, correlating with the recruitment of TSN. The slicer activity of TgAgo was Mg(2+)-dependent and required perfect complementarity between the guide RNA and the target. In contrast, the TSN activity was Ca(2+) -dependent and required an imperfectly paired guide RNA. Ago knockout parasites showed essentially normal growth, but in contrast, the PRMT1 knockouts grew abnormally. Chemical inhibition of Arg-methylation also had an anti-parasitic effect. These results suggest that the parasitic PRMT1 plays multiple roles, and its loss affects the recruitment of a more potent second slicer to the parasitic RNA silencing complex, the exact mechanism of which remains to be determined.     

β-Catenin gain of function in muscles impairs neuromuscular junction formation

Neuromuscular junction (NMJ) formation requires proper interaction between motoneurons and muscle cells. β-Catenin is required in muscle cells for NMJ formation. To understand underlying mechanisms, we investigated the effect of β-catenin gain of function (GOF) on NMJ development. In HSA-β-cat(flox(ex3)/+) mice, which express stable β-catenin specifically in muscles, motor nerve terminals became extensively defasciculated and arborized. Ectopic muscles were observed in the diaphragm and were innervated by ectopic phrenic nerve branches. Moreover, extensive outgrowth and branching of spinal axons were evident in the GOF mice. These results indicate that increased β-catenin in muscles alters presynaptic differentiation. Postsynaptically, AChR clusters in HSA-β-cat(flox(ex3)/+) diaphragms were distributed in a wider region, suggesting that muscle β-catenin GOF disrupted the signal that restricts AChR clustering to the middle region of muscle fibers. Expression of stable β-catenin in motoneurons, however, had no effect on NMJ formation. These observations provide additional genetic evidence that pre- and postsynaptic development of the NMJ requires an intricate balance of β-catenin activity in muscles.     

Hairy root cultures of butterfly pea (Clitoria ternatea L.): Agrobacterium × plant factors influencing transformation

Transformed rhizoclones were developed from Agrobacterium-treated explants of the medicinally important twinning legume Clitoria ternatea L. Several key factors influencing transformation events were optimized. A4T was the most infectious among the strains employed. Internode segments were more responsive than leaves, outdoor-grown explants preferred to those from in vitro cultures. High frequency transformation, resulting in up to 85.8% rhizogenesis, was attained using pre-pricked internodal explants for immersion (10 min) in Agrobacterium rhizogenes suspension grown overnight with acetosyringone (100 μM) to an OD₆₆₀ ≅ 0.6, diluted to a density of 10⁹ cells ml⁻¹, followed by 5-day co-cultivation. Roots were individually cultured in MS0 supplemented with the bacteriostatic antibiotic cefotaxime (500 μg ml⁻¹). Rhizoclones were renewed through successive subcultures in MS0 under diffused illumination. The T _L -DNA rolB and rolC ORF were detected in rhizoclones through PCR amplification. The T _R -DNA gene encoding mannopine synthase (man2) was revealed by positive amplification and opine gene expression substantiated by agropine and mannopine biosynthesis in all selected transformed rhizoclones. The implication of such findings is discussed on the context of utilization of such genetically transformed root cultures towards sustainable production of medicinally useful phytocompounds, besides providing a means for plant conservation.