Alan Hsu

TLR3 and MDA5 signalling, although not expression, is impaired in asthmatic epithelial cells in response to rhinovirus infection.

Rhinoviruses (RV) are the most common acute triggers of asthma, and airway epithelial cells are the primary site of infection. Asthmatic bronchial epithelial cells (BECs) have been found to have impaired innate immune responses to RV. RV entry and replication is recognized by pathogen recognition receptors (PRRs), specifically toll‐like receptor (TLR)3 and the RNA helicases; retinoic acid‐inducible gene I (RIG‐I) and melanoma differentiation‐associated gene 5 (MDA5).

MicroRNA Profiling Reveals a Role for MicroRNA-218-5p in the Pathogenesis of Chronic Obstructive Pulmonary Disease

Rationale: Aberrant expression of microRNAs (miRNAs) can have a detrimental role in disease pathogenesis. Objectives: To identify dysregulated miRNAs in lung tissue of patients with chronic obstructive pulmonary disease (COPD). Methods: We performed miRNA and mRNA profiling using high throughput stem‐loop reverse‐transcriptase quantitative polymerase chain reaction and mRNA microarray, respectively, on lung tissue of 30 patients (screening cohort) encompassing 8 never‐smokers, 10 smokers without airflow limitation, and 12 smokers with COPD. Differential expression of miRNA‐218‐5p (miR‐218‐5p) was validated by reverse‐transcriptase quantitative polymerase chain reaction in an independent cohort of 71 patients, an in vivo murine model of COPD, and primary human bronchial epithelial cells. Localization of miR‐218‐5p was assessed by in situ hybridization. In vitro and in vivo perturbation of miR‐218‐5p combined with RNA sequencing and gene set enrichment analysis was used to elucidate its functional role in COPD pathogenesis. Measurements and Main Results: Several miRNAs were differentially expressed among the different patient groups. Interestingly, miR‐218‐5p was significantly down‐regulated in smokers without airflow limitation and in patients with COPD compared with never‐smokers. Decreased pulmonary expression of miR‐218‐5p was validated in an independent validation cohort, in cigarette smoke‐exposed mice, and in human bronchial epithelial cells. Importantly, expression of miR‐218‐5p strongly correlated with airway obstruction. Furthermore, cellular localization of miR‐218‐5p in human and murine lung revealed highest expression of miR‐218‐5p in the bronchial airway epithelium. Perturbation experiments with a miR‐218‐5p mimic or inhibitor demonstrated a protective role of miR‐218‐5p in cigarette smoke‐induced inflammation and COPD. Conclusions: We highlight a role for miR‐218‐5p in the pathogenesis of COPD.

A pathogenic role for tumor necrosis factor-related apoptosis-inducing ligand in chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a life-threatening inflammatory respiratory disorder, often induced by cigarette smoke (CS) exposure. The development of effective therapies is impaired by a lack of understanding of the underlining mechanisms. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a cytokine with inflammatory and apoptotic properties. We interrogated a mouse model of CS-induced experimental COPD and human tissues to identify a novel role for TRAIL in COPD pathogenesis. CS exposure of wild-type mice increased TRAIL and its receptor messenger RNA (mRNA) expression and protein levels, as well as the number of TRAIL+CD11b+ monocytes in the lung. TRAIL and its receptor mRNA were also increased in human COPD. CS-exposed TRAIL-deficient mice had decreased pulmonary inflammation, pro-inflammatory mediators, emphysema-like alveolar enlargement, and improved lung function. TRAIL-deficient mice also developed spontaneous small airway changes with increased epithelial cell thickness and collagen deposition, independent of CS exposure. Importantly, therapeutic neutralization of TRAIL, after the establishment of early-stage experimental COPD, reduced pulmonary inflammation, emphysema-like alveolar enlargement, and small airway changes. These data provide further evidence for TRAIL being a pivotal inflammatory factor in respiratory diseases, and the first preclinical evidence to suggest that therapeutic agents that target TRAIL may be effective in COPD therapy.

Immunological axis of curcumin-loaded vesicular drug delivery systems

Several vesicular systems loaded with curcumin have found their way in the therapeutic applications of several diseases, primarily acting through their immunological pathways. Such systems use particles at a nanoscale range, bringing about their intended use through a range of complex mechanisms. Apart from delivering drug substances into target tissues, these vesicular systems also effectively overcome problems like insolubility and unequal drug distribution. Several mechanisms are explored lately by different workers, and interest over vesicular curcumin has been renewed in the past decade. This commentary discusses several immunological targets in which curcumin is employed in a vesicular form.

Vesicular Systems Containing Curcumin and Their Applications in Respiratory Disorders – A Mini Review

BACKGROUND Vesicular systems like nanotechnology and liposomes are gaining tremendous attention lately in the field of respiratory diseases. These formulations enhance bioavailability of the drug candidate, which could be achieved through a novel drug delivery mechanism. Moreover, the therapeutic potential achieved through these systems is highly controllable over long durations of time providing better efficacy and patient compliance. OBJECTIVE The objective of this paper is to review the recent literature on vesicular drug delivery systems containing curcumin. METHODS We have collated and summarized various recent attempts made to develop different controlled release drug delivery systems containing curcumin which would be of great interest for herbal, formulation and biological scientists. There are several vesicular nanotechnological techniques involving curcumin which have been studied recently, targeting pulmonary diseases. RESULTS Different vesicular systems containing curcumin are being studied for their therapeutic potential in different respiratory diseases. There has been a renewed interest in formulations containing curcumin recently, primarily owing to the broad spectrum therapeutic potential of this miracle substance. Various types of formulations, containing curcumin, targeting different bodily systems have recently emerged and, nevertheless, the search for newer frontiers with this drug goes on. CONCLUSION This mini review, in this direction, tries to highlight the key research interventions employing vesicular systems of drug delivery with curcumin.

Assessing the potential of liposomes loaded with curcumin as a therapeutic intervention in asthma

Curcumin a component of turmeric, which is derived from Curcuma longa is used as a colouring agent and as a dietary spice for centuries. Extensive studies have been done on the anti-inflammatory activity of curcumin along with its molecular mechanism involving different signalling pathways. However, the physicochemical and biological properties such as poor solubility and rapid metabolism of curcumin have led to low bioavailability and hence limits its application. Current therapies for asthma such as bronchodilators and inhaled corticosteroids (ICS) are aimed at controlling disease symptoms and prevent asthma exacerbation. However, this approach requires lifetime therapy and is associated with a constellation of side effects. This creates a clear unmet medical need and there is an urgent demand for new and more-effective treatments. The present study is aimed to formulate liposomes containing curcumin and evaluate for its anti-inflammatory effects on lipopolysaccharide (LPS)-induced inflammation on BCi-NS1.1 cell line. Curcumin and salbutamol liposomes were formulated using lipid hydration method. The prepared liposomes were characterized in terms of particle size, zeta potential, encapsulation efficiency and in-vitro release profile. The liposomes were tested on BCI-NS1.1 cell line to evaluate its anti-inflammatory properties. The various pro-inflammatory markers studied were Interleukin-6 (IL-6), Interleukin-8 (IL-8), Interleukin-1β (IL-1β) and Tumour Necrosis Factor-a (TNF-a). Additionally, molecular mechanics simulations were used to elucidate the positioning, energy minimization, and aqueous dispersion of the liposomal architecture involving lecithin and curcumin. The prepared curcumin formulation showed an average size and zeta potential of 271.3 ± 3.06 nm and -61.0 mV, respectively. The drug encapsulation efficiency of liposomal curcumin is 81.1%. Both curcumin-loaded liposomes formulation (1 μg/mL, 5 μg/mL) resulted in significant (p < 0.05) reduction in the level of pro-inflammatory marker expression such as IL-6, IL-8, IL-1β and TNF-a compared to positive control group. Liposomal curcumin with the dose of 1 μg/mL reduced the inflammatory markers more effectively compared to that of 5 μg/mL. Liposomal curcumin could be a promising intervention for asthma therapy showing their efficacy in suppressing the important pro-inflammatory markers involved in the pathogenesis of asthma.

Bromodomain inhibitors reverse inflammation and disease features in experimental chronic obstructive pulmonary disease

CD4+Foxp3+ regulatory T cells (Tregs) are the main regulators of peripheral tolerance and prevent the development of fatal autoimmune disease in humans and mice. Furthermore, Tregs have also been implicated in suppressing anti-tumour immune responses and are often enriched at sites of primary and metastatic tumours. While studies have shown the effect of Treg ablation on the control of primary tumours, few studies have examined their contribution to metastasis progression. In this thesis I hypothesised that the depletion of Tregs could promote control over metastasis. To address this, a highly metastatic murine mammary carcinoma cell line 4T1 was injected into transgenic mice expressing the diphtheria toxin receptor in Foxp3+ cells. Foxp3+ cells were depleted by administration of diphtheria toxin and the impact of this on growth of primary tumours and metastases was assessed and measured in vitro clonogenic assays. Results of these experiments indicated that Tregdepletion led to control of primary tumour growth and in some mice to control of metastases. Control of metastases was linked to control of primary tumour growth. In order to measure metastasis in vivo, a PET/CT imaging technique was optimized. Primary tumours and large metastatic nodules were successfully imaged in mice using F18 FDG as a radiotracer. However, the studies described herein revealed that micrometastases in mouse lungs were too small to be reliably identified using PET data parameters. CT imaging did however enable detection of increases in tissue density within the lungs, which was suggestive of micrometastases. Data obtained in this way also indicated that Treg-depletion promotes control of metastasis in some mice. Collectively, the findings described in this thesis indicate that Tregdepletion can contribute to control of metastatic disease and should therefore represent an important component of novel immunotherapies.Changes in microbiome, mucosal immunity and intestinal integrity have been associated with the onset of Type 1 Diabetes (T1D) in children. Toll-like Receptors (TLR) have been associated all three factors. The role of TLR and their effects on microbiome in autoimmunity were studied by crossing TLR1,2,4,6,9 and MyD88 targeted deficiency mutations to the type 1 diabetes (T1D)-prone NOD mouse strain. While NOD.Tlr9-/- and NOD.Tlr6-/- mice were unaffected, T1D in NOD.Tlr4-/- and NOD.Tlr1-/- mice was exacerbated and that in NOD.Myd88-/- and NOD.Tlr2-/- mice ameliorated. Physical parameters of the intestines were compared; ileal weight was reduced in NOD.Tlr1-/-mice. Similarly, by histology, these mice had reduced villus length and width. The intestinal microbiomes of NOD wild-type (WT), NOD.Tlr1-/-, NOD.Tlr2-/- and NOD.Tlr4-/- mice were compared by high throughput sequencing of 16S ribosomal DNA (rDNA), in two cohorts, 18 months apart. Analysis of caecal 16S sequences clearly resolved the mouse lines and there were significant differences in beta diversity between the strains, with individual bacterial species contributing greatly to the differences in the microbiota of individual TLR-deficient strains. To test the relationship between microbiome and T1D, all strains were re-derived onto the parental NOD/Lt line and the incidence of T1D re-assessed within two generations. All rederived lines expressed an incidence of disease similar to that of the parental line. TLR deficiencies are associated with changes in microbiome; changes of microbiome are associated with T1D; the effects of TLR deficiencies on T1D appear to be mediated by their effects on gut flora.Intestinal TCRb+CD4-CD8b-CD8a+ (CD8aa) IELs alleviate T cell induced colitis and have been suggested to play a role in virus infection and cancer. Their thymic development has been elucidated to some extent, as IEL precursors (IELp) are known to be CD4-CD8-CD5+TCRb+, but is not yet fully understood. Within the thymus, mature IELp were identified based on their expression of CD122 and MHC class I. Two major phenotypic subsets exist within this mature thymic IELp population: a PD1+Tbet- population that preferentially expresses a4b7, and a PD1-Tbet+ population with preferential CD103 expression. These two populations were also distinct in their Valpha repertoire. The PD1+a4b7+ population contains clones that are strongly self-reactive as judged by Nur77GFP and their dramatic increase in Bim deficient mice, while the PD1-Tbet+ population did not show these characteristics. Both gave rise to CD8aa IELs upon adoptive transfer into RAG-/- recipients. However intrathymic labeling revealed that PD1+a4b7+ IELp were the major thymic emigrating population, and emigration was S1P1-dependent. In contrast, PD1-Tbet+ IELp expressed CXCR3, were retained, and accumulated in the thymus with age. Preliminary immunofluorescence data furthermore indicate differential thymic cortico-medullary localization of the IELp subtypes. These experiments more precisely define the behavior of IEL precursors.