Remote lung injury after experimental intestinal ischemia-reperfusion in horses.

Ischemia followed by reperfusion leads to release of toxic molecules into the circulation, and these molecules may cause injury in remote organs such as the lung. Horses commonly suffer from episodes of intestinal ischemia-reperfusion (IR) due to intestinal twisting/strangulation followed by repair. Because there is no evidence of lung injury associated with IR in horses, we designed a study to characterize the intestinal IR-associated lung inflammation and determine the effect of lidocaine on lung inflammation in IR horses. Lung tissues were collected from non-anesthetized (n=4) and anesthetized (n=4) control horses and horses (n=12) after 70 minutes of ischemia followed by 60 minutes of reperfusion. Horses in IR groups received Lactated Ringer's Solution (LRS; n=6) or lidocaine (n=6) intravenously. Control lungs had normal histology but lungs from IR horses showed moderate accumulation of neutrophils in blood vessels and airways. We found increased staining for TLR4, IL-8, TLR9, and von Willebrand factor (vWF) along with aggregates of vWF-positive platelets in lung vessels of IR horses compared to the controls. Lung TNFα was significantly increased in IR horses compared to the control horses (P<0.05). Neutrophil numbers, but not MPO concentrations, were significantly lower, while macrophage numbers were higher in the IR group receiving lidocaine compared to the LRS horses (P<0.05). We conclude that intestinal IR leads to remote lung injury characterized by recruitment of inflammatory cells and expression of inflammatory molecules in horses, and lidocaine may ameliorate lung inflammation following intestinal IR.

RGD-tagged helical rosette nanotubes aggravate acute lipopolysaccharide-induced lung inflammation.

Rosette nanotubes (RNT) are a novel class of self-assembled biocompatible nanotubes that offer a built-in strategy for engineering structure and function through covalent tagging of synthetic self-assembling modules (G∧C motif). In this report, the G∧C motif was tagged with peptide Arg-Gly-Asp-Ser-Lys (RGDSK-G∧C) and amino acid Lys (K-G∧C) which, upon co-assembly, generate RNTs featuring RGDSK and K on their surface in predefined molar ratios. These hybrid RNTs, referred to as K(x)/RGDSK(y)-RNT, where x and y refer to the molar ratios of K-G∧C and RGDSK-G∧C, were designed to target neutrophil integrins. A mouse model was used to investigate the effects of intravenous K(x)/RGDSK(y)-RNT on acute lipopolysaccharide (LPS)-induced lung inflammation. Healthy male C57BL/6 mice were treated intranasally with Escherichia coli LPS 80 µg and/or intravenously with K9°/RGDSK¹°-RNT. Here we provide the first evidence that intravenous administration of K9°/RGDSK¹°-RNT aggravates the proinflammatory effect of LPS in the mouse. LPS and K9°/RGDSK¹°-RNT treatment groups showed significantly increased infiltration of polymorphonuclear cells in bronchoalveolar lavage fluid at all time points compared with the saline control. The combined effect of LPS and K9°/RGDSK¹°-RNT was more pronounced than LPS alone, as shown by a significant increase in the expression of interleukin-1ß, MCP-1, MIP-1, and KC-1 in the bronchoalveolar lavage fluid and myeloperoxidase activity in the lung tissues. We conclude that K9°/RGDSK¹°-RNT promotes acute lung inflammation, and when used along with LPS, leads to exaggerated immune response in the lung.

Rosette nanotubes inhibit bovine neutrophil chemotaxis.

Migration of activated neutrophils that have prolonged lifespan into inflamed organs is an important component of host defense but also contributes to tissue damage and mortality. In this report, we used biologically-inspired RGD-tagged rosette nanotubes (RNT) to inhibit neutrophil chemotaxis. We hypothesize that RGD-RNT will block neutrophil migration through inhibition of MAPK. In this report, RNT conjugated to lysine (K-RNT) and arginine-glycine-aspartic acid-serine-lysine (RGDSK-RNT) were co-assembled in a molar ratio of 95/5. The effect of the resulting composite RNT (RGDSK/K-RNT) on neutrophil chemotaxis, cell signaling and apoptosis was then investigated. Exposure to RGDSK/K-RNT reduced bovine neutrophil migration when compared to the non-treated group (p<0.001). Similar effect was seen following treatment with ERK1/2 or p38 MAPK inhibitors. Phosphorylation of the ERK1/2 and p38 MAPK was inhibited at 5 min by RGDSK/K-RNT (p<0.05). The RGDSD/K-RNT did not affect the migration of neutrophils pre-treated with αvß3 integrin antibody suggesting that both bind to the same receptor. RGDSK/K-RNT did not induce apoptosis in bovine neutrophils, which was suppressed by pre-exposing them to LPS (p<0.001). We conclude that RGDSK/K-RNT inhibit phosphorylation of ERK1/2 and p38 MAPK and inhibit chemotaxis of bovine neutrophils.

Expression of toll-like receptor 9 in horse lungs.

Toll-like receptor 9 (TLR9) has been found to be the main receptor to respond to bacterial DNA in a wide variety of species. Recent work has shown that TLR9 is expressed in a diverse set of cells within the lung. However, much of this data has been centered on human and mouse cell culture lines or primary cultures and very little is known of TLR9 expression in intact lung, especially that of the horse. Here we show that TLR9 is expressed in the lungs of horses in a wide variety of cells. In particular, we note expression in pulmonary intravascular macrophages (PIMs), alveolar macrophages, bronchial epithelial cells, and type-II cells amongst others. Immunogold electron microscopy localized TLR9 in nuclei, cytoplasm, and plasma membrane of various lung cells. The data also show that E. coli lipopolysaccharide significantly increased expression of TLR9 mRNA in lungs and the number of cells in the lung septa that were positive for TLR9 protein. Protein expression was seen in airway epithelium, vascular endothelium, and inflammatory cells in blood vessels. Intravenous administration of gadolinium chloride, which depletes macrophages, before the lipopolysaccharide treatment significantly inhibited the LPS-induced increase in TLR9 mRNA in the lungs of the horses. We conclude that TLR9 is expressed in lung cells including PIMs and that the lipopolysaccharide treatment increases TLR9 mRNA expression. The increase in TLR9 mRNA is eliminated by depletion of PIMs, implicating these cells as a major source of TLR9 in the equine lung.

Transgenic expression of coat protein gene of Rice tungro bacilliform virus in rice reduces the accumulation of viral DNA in inoculated plants.

Rice tungro, a devastating disease of rice in south and southeast Asia, is caused by the joint infection of Rice tungro bacilliform virus (RTBV) and Rice tungro spherical virus (RTSV). In order to obtain transgenic resistance against RTBV, indica rice cultivar Pusa Basmati-1 was transformed to express the coat protein (CP) gene of an Indian isolate of RTBV. Rice plants containing the transgene integrated in low copy numbers were obtained, in which the CP was shown to accumulate in the leaf tissue. The progenies representing three independent transformation events were challenged with Indian isolates of RTBV using viruliferous Green leafhoppers, and the viral titers in the inoculated plants were monitored using DNA dot-blot hybridization. As compared to non-transgenic controls, two independent transgenic lines showed significantly low levels of RTBV DNA, especially towards later stages of infection and a concomitant reduction of tungro symptoms.

Role of Toll-like receptor 4 in lung inflammation following exposure to swine barn air.

The authors tested a hypothesis that lung inflammation and airway hyperresponsiveness (AHR) induced following barn air exposure are dependent on Toll-like receptor 4 (TLR4) by exposing C3HeB/FeJ (intact TLR4, wild type [WT]) and C3H/HeJ (defective TLR4, mutant) mice either to the barn air (8 hours/day for 1, 5, or 20 days) or ambient air. Both strains of mice, compared to their respective controls, showed increased AHR following 5 exposures but dampened AHR after 20 exposures to show lack of effect of TLR4 on AHR. However, swine barn air induced lung inflammation with recruitment of inflammatory cells and cytokine expression was observed in WT but not in mutant mice. These data show different roles of TLR4 in lung inflammation and AHR in mice exposed to swine barn air.

Nanotechnology-based drug delivery systems.

Nanoparticles hold tremendous potential as an effective drug delivery system. In this review we discussed recent developments in nanotechnology for drug delivery. To overcome the problems of gene and drug delivery, nanotechnology has gained interest in recent years. Nanosystems with different compositions and biological properties have been extensively investigated for drug and gene delivery applications. To achieve efficient drug delivery it is important to understand the interactions of nanomaterials with the biological environment, targeting cell-surface receptors, drug release, multiple drug administration, stability of therapeutic agents and molecular mechanisms of cell signalling involved in pathobiology of the disease under consideration. Several anti-cancer drugs including paclitaxel, doxorubicin, 5-fluorouracil and dexamethasone have been successfully formulated using nanomaterials. Quantom dots, chitosan, Polylactic/glycolic acid (PLGA) and PLGA-based nanoparticles have also been used for in vitro RNAi delivery. Brain cancer is one of the most difficult malignancies to detect and treat mainly because of the difficulty in getting imaging and therapeutic agents past the blood-brain barrier and into the brain. Anti-cancer drugs such as loperamide and doxorubicin bound to nanomaterials have been shown to cross the intact blood-brain barrier and released at therapeutic concentrations in the brain. The use of nanomaterials including peptide-based nanotubes to target the vascular endothelial growth factor (VEGF) receptor and cell adhesion molecules like integrins, cadherins and selectins, is a new approach to control disease progression.