Src-type tyrosine kinase p56lck is critical for thymic stromal lymphopoietin-induced allergic rhinitis.

BACKGROUND: Thymic stromal lymphopoietin (TSLP) is a regulator of mast cell-mediated allergic inflammatory reactions, but the manner in which TSLP contributes to allergic rhinitis (AR) remains unclear. OBJECTIVE: Here, we sought to determine that TSLP plays a crucial role in AR by interacting with Src-type tyrosine kinase p56lck and STAT6 and promoting mast cells degranulation. METHODS: The effects of TSLP on mast cell degranulation and AR were analysed in human mast cell line (HMC-1 cells), ovalbumin (OVA)-induced AR animal model, and human subjects. Small interfering RNA experiments were performed in HMC-1 cells and OVA-induced AR model. Immune responses were analysed by enzyme-linked immunosorbent assay, Western blotting, immunoprecipitation, and histological studies. RESULTS: Thymic stromal lymphopoietin levels and mast cell-derived p56lck activation were elevated in human subjects with AR, and in AR mice, exogenous TSLP accelerated TH2-allergic inflammatory reactions by up-regulating p56lck and STAT6. On the other hand, depletion of TSLP, p56lck, and STAT6 ameliorated clinical symptoms in AR mice. The selective inhibitor of p56lck, damnacanthal, inhibits AR reactions. CONCLUSION: Collectively, these observations suggest a role for TSLP/p56lck/STAT6 in AR and offer insight into potential therapeutic strategies.

Generation of embryonic stem-like cells from in vivo-derived porcine blastocysts at a low concentration of basic fibroblast growth factor.

Although basic fibroblast growth factor (bFGF) is an essential factor supporting the maintenance of porcine embryonic stem (ES) cell self-renewal and pluripotency, its high cost has limited previous studies, and the development of a low-cost culture system is required. For these systems, in vivo blastocysts were progressively cultured under various conditions consisting of different culture mediums and/or different feeder cell numbers at a low concentration of bFGF. As the results, the sequential culture of in vivo-derived porcine blastocysts on 5.0 × 105 mouse embryonic fibroblast (MEF) feeder cells in alpha minimum essential medium-based medium for primary culture, on 2.5 × 105 MEF feeder cells in Mixture medium for the 1st subpassage, and on 2.5 × 105 MEF feeder cells in DMEM/Ham's F10-based medium for the post-2nd subpassage could support the establishment and maintenance of porcine ES-like cells at the low concentration of bFGF. The established porcine ES-like cells showed ES cell-specific characteristics such as self-renewal and pluripotency. We confirmed that porcine ES-like cells could be generated from in vivo-derived porcine blastocysts at a low concentration of bFGF.

Determination of feeder cell-based cellular niches supporting the colonization and maintenance of spermatogonial stem cells from prepubertal domestic cat testes.

Recently, isolation and in vitro culture of putative spermatogonial stem cells (SSCs) in the domestic cat have been conducted. However, the cellular niche conditions that facilitate the establishment and long-term maintenance of feline SSCs (FSSCs) have not been described. Therefore, we investigated the type of feeder cells used to stimulate colony formation and growth of FSSCs among the various factors in the FSSC niche. Spermatogonial stem cells isolated from feline testes were cultured on mitotically inactivated testicular stromal cells (TSCs) derived from cats, dogs and mice, and mouse embryonic fibroblasts (MEFs). The formation and growth of colonies derived from SSCs cultured on each type of feeder cell were identified at passage 0, and the morphology, alkaline phosphatase (AP) activity and expression of SSC-specific genes in surviving colonies were investigated at passage 4. Among these diverse feeder cells, TSCs from cat showed the greatest colony formation, growth and maintenance of FSSCs, and SSC colonies cultured by passage 4 showed a typical dome-shaped morphology, AP activity and expression of SSC-specific genes (NANOG, OCT4, SOX2 and CD9). Accordingly, these results demonstrate that feline TSCs could be used as feeder cells to support the establishment and maintenance of SSCs from domestic cats.

Broadband multi-layer terahertz metamaterials fabrication and characterization on flexible substrates.

Microscopic split-ring-resonator (SRR) arrays are fabricated on 100 µm thick polyethylene naphthalate (PEN) films by femtosecond laser micro-lens array (MLA) lithography. The transmission properties of these metamaterials are characterized by THz Time Domain Spectroscopy (THz-TDS). Tunable resonance responses can be achieved by changing SRR structural design parameters. By stacking 2D PEN metamaterial films with different frequency responses together, a broadband THz filter with full width at half maximum (FWHM) of 0.38 THz is constructed. The bandwidth of the resonance response increases up to 4.2 times as compared to the bandwidths of single layer metamaterials. Numerical simulation reveals that SRR layers inside the multi-layer metamaterials are selectively excited towards specific frequencies within the broadband response. Meanwhile, more than one SRR layers respond to the chosen frequencies, resulting in the enhancement of the resonance properties. The multi-layer metamaterials provide a promising way to extend SRR based metamaterial operating region from narrowband to broadband with a tunable feature.

Hybrid metamaterial design and fabrication for terahertz resonance response enhancement.

Planar hybrid metamaterial with different split ring resonators (SRR) structure dimensions are fabricated on silicon substrates by femtosecond (fs) laser micro-lens array (MLA) lithography and lift-off process. The fabricated metamaterial structures consist of: (a) uniform metamaterial with 4 SRRs at same design and dimension as a unit cell and (b) hybrid metamaterial with 4 SRRs at same design but different dimensions as a unit cell. The electromagnetic field responses of these hybrid and single dimension metamaterial structures are characterized using a terahertz (THz) time-domain spectroscopy. Transmission spectra of these metamaterial show that a broader resonance peak is formed when 2 SRRs are close to each other. FDTD simulation proves that there is a strong mutual coupling between 2 SRRs besides a strong localized electric field at the split gap, which can enhance the electric field up to 364 times for tunable, broad band and high sensitivity THz sensing. Meanwhile, the strong coupling effect could lead to the formation of an additional resonance peak at approximately 0.2 THz in the THz spectra regime.