Advanced application of stimuli-responsive drug delivery system for inflammatory arthritis treatment.

Inflammatory arthritis is a major cause of disability in the elderly. This condition causes joint pain, loss of function, and deterioration of quality of life, mainly due to osteoarthritis (OA) and rheumatoid arthritis (RA). Currently, available treatment options for inflammatory arthritis include anti-inflammatory medications administered via oral, topical, or intra-articular routes, surgery, and physical rehabilitation. Novel alternative approaches to managing inflammatory arthritis, so far, remain the grand challenge owing to catastrophic financial burden and insignificant therapeutic benefit. In the view of non-targeted systemic cytotoxicity and limited bioavailability of drug therapies, a major concern is to establish stimuli-responsive drug delivery systems using nanomaterials with on-off switching potential for biomedical applications. This review summarizes the advanced applications of triggerable nanomaterials dependent on various internal stimuli (including reduction-oxidation (redox), pH, and enzymes) and external stimuli (including temperature, ultrasound (US), magnetic, photo, voltage, and mechanical friction). The review also explores the progress and challenges with the use of stimuli-responsive nanomaterials to manage inflammatory arthritis based on pathological changes, including cartilage degeneration, synovitis, and subchondral bone destruction. Exposure to appropriate stimuli induced by such histopathological alterations can trigger the release of therapeutic medications, imperative in the joint-targeted treatment of inflammatory arthritis.

A TCR-like antibody against a proinsulin-containing fusion peptide ameliorates type 1 diabetes in NOD mice.

Type 1 diabetes (T1D) is an autoimmune disease caused by destruction of insulin-producing ß cells. The response of autoreactive T cells to ß cell antigens plays a central role in the development of T1D. Recently, fusion peptides composed by insulin C-peptide fragments and other proteins were reported as ß cell target antigens for diabetogenic CD4+ T cells in non-obese diabetic (NOD) mice. In this study, we generated a T cell-receptor (TCR)-like monoclonal antibody (mAb) against a fusion peptide bound to major histocompatibility complex (MHC) class II component to elucidate the function of the fusion peptides in T1D. In addition, we developed a novel NFAT-GFP TCR reporter system to evaluate the TCR-like mAb. The NFAT-GFP reporter T cells expressing the diabetogenic TCR were specifically activated by the fusion peptide presented on the MHC class II molecules. By using the NFAT-GFP reporter T cells, we showed that the TCR-like mAb blocks the diabetogenic T cell response against the fusion peptide presented on the MHC class II molecules. Furthermore, the development of T1D was ameliorated when pre-diabetic NOD mice were treated with this mAb. These findings suggest that NFAT-GFP reporter T cells are useful to assess the function of specific TCR and the recognition of fusion peptides by T cells is crucial for the pathogenesis of T1D.

Distribution of TLR4 and MHC class II molecules of the spleen in broiler chicks treated with and without LPS in the first 2 weeks of the post-hatch period.

1. The purpose of this study was to investigate the distribution of Toll-like receptor-4 (TLR4) and major histocompatibility complex (MHC) class II molecules of the spleen in chicks treated with lipopolysaccharide (LPS) during the first 2 weeks of their life. 2. A total of 225 Ross-308 commercial broiler chicks were used. Within the 2-week experimental period, chicks were divided into 5 main groups according to the days of decapitation which were 1, 4, 7, 10 and 14 d after hatch. Each main group had 45 chicks. The main groups were further divided into three subgroups (15 chicks each), which included control chicks (no injection), and phosphate-buffered saline (PBS) and LPS-injected chicks. Spleen samples were collected 1-, 3-, 6-, 12- and 24-h after the PBS or LPS administrations. Tissue sections were stained using streptavidin-biotin-peroxidase complex staining method. 3. From 1 d of age, TLR4 positivity was found in the spleen in diffuse granular form. The cells showing intense TLR4 positivity were observed in periellipsoidal lymphoid tissue in 4-d-old chicks. The same cells were determined in the germinal centre of the spleen in 7-d-old chicks. LPS stimulation led to an increase in the intensity of TLR4 positivity in 14-d-old chicks. 4. From 1 d of age, MHC class II positivity was found in both white pulp and red pulp. This was higher in 14-d-old chicks injected with LPS than in the controls and the chicks injected with PBS. 5. The findings indicate that, from 1 d of age in chicks, the spleen has both non-specific defence elements and the molecules having the information to induce adaptive immunity. In addition, at the end of the 2-week experimental period, it was determined that the spleen had the capacity to recognise antigens.

RhoB induces the production of proinflammatory cytokines in TLR-triggered macrophages.

Toll-like receptors (TLRs) are the primary sensors detecting conserved molecular patterns on microorganisms, thus acting as important components of innate immunity against invading pathogens. Many positive and negative regulators of TLR-triggered signaling have been identified. The Rho GTPase RhoB plays a key role in cell migration, division and polarity; however, the function and regulatory mechanisms of RhoB in TLR ligand-triggered innate immune responses remain to be investigated. Here, we report that the expression of RhoB is induced by TLR agonists (lipopolysaccharide (LPS), CpG, poly(I:C)) in macrophages. Knockdown of RhoB expression markedly decreased TLR ligand-induced activation of mitogen activated protein kinases and nuclear factor-κB (NF-κB), and the production of tumor necrosis factor α (TNFα), interleukin (IL)-6 and IL-1ß in macrophages stimulated with TLR ligands. Furthermore, we demonstrated that RhoB interacts with major histocompatibility complex class II (MHCII) α chain, but not ß chain, in endosomes of macrophages. Knockdown of MHCII expression greatly reduced the interaction of RhoB with Btk, and attenuated the induction of NF-κB and interferon ß activity by RhoB upon LPS stimulation. These findings suggest that RhoB is a positive physiological regulator of TLRs signaling via binding to MHCII in macrophages, and therefore RhoB may be a potential therapeutic target in inflammatory diseases.

Heterogeneous Nuclear Ribonucleoprotein A2B1 Exerts a Regulatory Role in Lipopolysaccharide-stimulated 38B9 B Cell Activation.

Major histocompatibility complex (MHC) class II molecules, which are recognized for their primary function of presenting an antigen to the T cell receptor, are involved in various signaling pathways in B cell activation. We identified heterogeneous nuclear ribonucleoprotein (hnRNP) A2B1 as an MHC class II molecule-associated protein involved in MHC class II-mediated signal transduction in lipopolysaccharide (LPS)-stimulated 38B9 B cells. Although the function of hnRNP A2B1 in the nucleus is primarily known, the level of hnRNP A2B1 in the cytoplasm was increased in LPS-stimulated 38B9 cells, while it was not detected in the cytoplasm of non-treated 38B9 cells. The silencing of hnRNP A2B1 expression using siRNA disturbed B cell maturation by regulation of mitogen-activated protein kinase signaling, NF-κB activation, and protein kinase B activation. These results suggest that hnRNP A2B1 is associated with MHC class II molecules and is involved in B cell activation signaling pathways in LPS-stimulated 38B9 cells.

Heterogeneous Nuclear Ribonucleoprotein A2B1 Exerts a Regulatory Role in Lipopolysaccharide-stimulated 38B9 B Cell Activation

Major histocompatibility complex (MHC) class II molecules, which are recognized for their primary function of presenting an antigen to the T cell receptor, are involved in various signaling pathways in B cell activation. We identified heterogeneous nuclear ribonucleoprotein (hnRNP) A2B1 as an MHC class II molecule-associated protein involved in MHC class II-mediated signal transduction in lipopolysaccharide (LPS)-stimulated 38B9 B cells. Although the function of hnRNP A2B1 in the nucleus is primarily known, the level of hnRNP A2B1 in the cytoplasm was increased in LPS-stimulated 38B9 cells, while it was not detected in the cytoplasm of non-treated 38B9 cells. The silencing of hnRNP A2B1 expression using siRNA disturbed B cell maturation by regulation of mitogen-activated protein kinase signaling, NF-κB activation, and protein kinase B activation. These results suggest that hnRNP A2B1 is associated with MHC class II molecules and is involved in B cell activation signaling pathways in LPS-stimulated 38B9 cells.

Age-Related Changes of MHC Class II-immunoreactive Dendritic Cells in Rat Brain / 대한소아신경학회지

PURPOSE: Dendritic cells are antigen presenting cells(APC) that express class II major histocompatibility complex gene products on their surface. Recently, it was proved that dendritic cells activate antitumor immunity for intracranial germ cell tumor. The aim of the present study is to investigate the age-related changes of MHC class II-immunoreactive dendritic cells in the rat brain. METHODS: Male rats(Sprague-Dawley) were sacrificed at 1 month, 12 months and 24 months after birth. Brains were removed and sliced in rat brain matrix. Brain slices were cryosectioned coronally at interaural 5.70-6.70 mm. Brain tissue sections were immunohistochemically reacted with monoclonal MHC class II antibody. RESULTS: MHC class II-immunoreactive dendritic cells were observed in choroid plexuses and white matter(corpus callosum, cerebral peduncle and external capsule). The number of MHC class II-immunoreactive dendritic cells was slightly increased with age. As age increases, shapes of MHC class II-immunoreactive dendritic cells became more complex and aggregated together. CONCLUSION: As age increases, MHC class II-immunoreactive dendritic cells in choroid plexuses and white matter of the brain became not only more complex in shape, but also increased in number to improve immunity.

The Effect of ECMs on MHC Class II Molecule Expression in Retinal Pigment Epithelium

Expression of MHC class II molecule by retinal pigment epithelial cells and the interaction of the cell with extracellular matrix molecules involve in the pathogenesis of proliferative vitreoretinopathy and chorioretinitis. In this study interferon-gammainduced the expression of MHC class II molecules on RPEJ cells. Extracellular matrix molecules increased the interferon-gamma-i n d u c e d expression of MHC class II molecules. TGF-beta2 inhibited the interferon-gammainduced expression of MHC class II molecules. However, there was no significant effect on such inhibitory function according to the types of extracellular matrix molecules. Blocking the autocrine effect of TGF-beta2 by the specific antisense oligonucleotides decreased its inhibitory function. PLC-gamma1-specific antisense oligonucleotide inhibited the effect of TGF-beta2, which suggests that PLC-gamma1 involves in the signal transduction of TGF-beta2 on the expression of MHC class II molecules. In conclusion, the present study provides further understandings to the previous knowledge of pathogenesis of immunologic retinal disorders.

Immunocytochemical Study on Distribution and Morphology of Dendritic Cells in the Tongue during Development and Growth of the Rat / 체질인류학회지

Activation of T cells for an immune response requires the participation of antigen presenting cells (APC) that express class II major histocompatibility complex gene products on their surface. Until recently, the macrophages have been considered to be the prime candidates for this role, but it is now recognized that other cells, including dendritic cells, B cells, activated T cells and endothelial cells, can present antigen effectively. Particularly, among them, dendritic cells (DC) are considered to be very efficient APC for various T -cell dependent immune responses in comparison with other types of APC. Nonlymphoid dendritic cells including Langerhans cells and interstitial dendritic cells strongly express the MHC class II products and have characteristic dendritic morphology. As far as we know, there is no study on the ontogeny of MHC class II -immunoreactive dendritic cells in the rat tongue. The aim of the present study is to investigate the ontogeny and morphological characterization of dendritic cells in the tongue of growing and developing rats. The distribution and morphology of the dendritic cells in the rat tongue were studied from the fetal 15 -day until 180 days after birth by means of immunocytochemical methods using anti -rat MHC class II monoclonal antibodies. The results were as follows: 1. MHC class II -immunoreactive dendritic cells were first found in the muscle layer of 17 -day fetus, and in the epithelium and lamina propria of the tongue at birth. 2. The number of MHC class II -immunoreactive dendritic cells was gradually increased with age, particularly, in the epithelium at 14th day, in the lamina propria at 14th day, and in the muscle layer at 21st day after birth. 3. Numbers of MHC class II -immunoreactive dendritic cells were higher in the dorsal part than in ventral part of the tongue at all developmental stages. Especially, dendritic cells were twice higher numbers in the epithelium, a little higher numbers in the lamina propria and almost same numbers in the muscle layer. 4. With age, shapes of MHC class II -immunoreactive dendritic cells were changed from round to dendritic and aggregated together. In conclusion, the above results suggest that the increases of the number and the changes of the morphology in MHC class II -immunoreactive dendritic cells, with age may influence on effects of cell -mediated immune responses.