Consumption of foods high in saturated fatty acids (FAs) as well as elevated levels of circulating free FAs are known to be associated with T2D. Though previous studies showed inflammation is crucially involved in the development of insulin resistance, how inflammation contributes to β cell dysfunction has remained unclear. We report here the saturated FA palmitate induces β cell dysfunction in vivo by activating inflammatory processes within islets. Through a combination of in vivo and in vitro studies, we show β cells respond to palmitate via the TLR4/MyD88 pathway and produce chemokines that recruit CD11b(+)Ly-6C(+) M1-type proinflammatory monocytes/macrophages to the islets. Depletion of M1-type cells protected mice from palmitate-induced β cell dysfunction. Islet inflammation also plays an essential role in β cell dysfunction in T2D mouse models. Collectively, these results demonstrate a clear mechanistic link between β cell dysfunction and inflammation mediated at least in part via the FFA-TLR4/MyD88 pathway.
Use of short interfering RNA (siRNA) is a promising new approach thought to have a strong potential to lead to rapid development of gene-oriented therapies. Here, we describe a newly developed, systemically injectable siRNA vehicle, the
X-ray absorption fine structure combined with X-ray fluorescence spectrometry was applied to various V+TiO2 hybrid samples. Emitted V K alpha1 fluorescence from the sample was selectively counted by using a high-energy-resolution (0.4 eV) spectrometer equipped with a Ge(331) crystal. Two advantages of this method, extremely high signal/background ratio and the compatibility of measurements in the atmosphere of reaction gas (in situ study in relation to heterogeneous catalysis), were effective at the V K-edge. Structure transformation of the V sites was spectroscopically followed for the V/TiO2 catalyst. The monooxo tetrahedral vanadate site was demonstrated to exist at 473 K. It transformed into dispersed species of 5-fold coordination in ambient air and further into polymeric VO(x) species in 0.85 kPa of water at 290 K. In the presence of 3.2 kPa of 2-propanol, dissociative adsorption of 2-propanol on the dispersed V species was strongly suggested at 290-473 K. In situ structure changes of V sites on TiO2 were reported by means of XAFS for the first time. The V(V) sites for the V/TiO2 catalysts were essentially identical with those for V supported on mesoporous (high-surface-area) TiO2 and V-TiO2 sample prepared by the sol-gel method. However, predominant V(IV) sites were found for mesoporous V-TiO2. The V(IV) sites substituted on the Ti sites of TiO2. When the molar ratio of V/Ti increased from 1/100 to 1/5.0, major octahedral V sites in the TiO2 matrix looked to transform into tetrahedral ones.
A 48-year-old female presented with an extremely rare primary tumor of the pineal region with papillary features manifesting as morning headaches persisting for 1 month. Magnetic resonance imaging showed a well-defined mass, with some cystic components, in the region of the pineal gland. The tumor was completely removed through an occipital transtentorial approach in the prone position. Histological examination found a distinctive papillary growth pattern in which the vessels were covered by multiple layers of tumor cells. The histological diagnosis was papillary tumor of the pineal region (PTPR), which has recently been described as a distinct clinicopathological entity requiring careful follow up because the prognosis is not well understood. Postoperatively, the patient has continued to do well, with no recurrence at the 8-month follow-up examination. PTPR should be considered in the differential diagnosis of pineal tumors. PTPR may have been frequently misinterpreted in the past as either ependymoma or choroid plexus papilloma due to the similar morphology.
RNA interference, mediated by small interfering RNA (siRNA), is effective in silencing genes with a high degree of specificity. To explore the therapeutic potential of systemically administered siRNA for rheumatoid arthritis (RA), we tested the complex of siRNA and the recently developed wrapsome (siRNA/WS) containing siRNA-encapsulated liposome in mice with collageninduced arthritis (CIA). Mice with CIA received an intravenous injection of Cy5-labeled siRNA/WS. Fluorescence stereoscopic microscopy and flow cytometry were used to assess the siRNA/WS tissue distribution. The efficacy of siRNA-targeting tumor necrosis factor (TNF)-␣/WS in CIA was evaluated by arthritis score. TNF-␣ mRNA levels in the joints were measured by real-time reverse transcriptase-polymerase chain reaction. The intensity of Cy5 fluorescence was higher in arthritic joints than in nonarthritic sites in Cy5-siRNA/WS-treated mice and remained higher up to 48 h after injection, compared with that in naked Cy5-siRNA-treated mice. Cy5 fluorescence intensity was higher in synovial cells than in splenocytes, bone marrow cells, and peripheral blood leukocytes. The majority of Cy5-positive synovial cells were CD11b ϩ with only a few CD3 ϩ cells. Treatment with TNF-␣ siRNA/WS resulted in significant decreases in severity of arthritis and TNF-␣ mRNA level in the joints compared with control siRNA/WS. In conclusion, the use of our WS allowed efficient and targeted delivery of siRNAs to arthritic joints. The siRNA/WS was mainly incorporated into CD11b ϩ cells, including macrophages and neutrophils, in the inflamed synovium, suggesting its potential therapeutic effects in RA by silencing the expression of inflammatory molecules produced by these cells.
Introduction of liposomes into target cells is important for drug delivery systems. For this purpose, the surface of the liposome is equipped with ligand peptides, which may bind to specific receptors on the cell membrane. An artificial novel lipopeptide (MSH-C4A2) containing the alpha-melanocyte-stimulating hormone (alpha-MSH) sequence and two long alkyl chains was designed and synthesized, and the liposome, composed of egg phosphatidylcholine (EPC) and MSH-C4A2, was prepared. The stability of the liposome was estimated by measuring calcein leakage from the liposome inner phase. The stability of the liposome decreased upon addition of MSH-A4C2, which seemed to be attributable to the amphiphilic property of the peptide moiety (alpha-MSH) of MSH-A2C4. The stability was, however, recovered fairly well upon addition of cholesterol (Ch) or phosphatidylglycerol (PG). It was concluded therefore that the ternary system, MSH-C4A2/Ch/EPC or MSH-C4A2/PG/EPC, is suitable for preparing the functional liposome.
The use of high‐shear microfluidization as a rapid, reproducible, and high‐yield method to prepare nanoparticles of porous silicon (pSi) with a narrow size distribution is described. Porous films prepared by electrochemical etch of a single‐crystal silicon wafer are removed from the substrate, fragmented, dispersed in an aqueous solution, and then processed with a microfluidizer, which generates high yields (57%) of pSi nanoparticles of narrow size distribution (PDI = 0.263) without a filtration step. Preparation of pSi nanoparticles via microfluidization improves yields (by 2.4‐fold) and particle size uniformity (by 1.8‐fold), and it lowers the total processing time (by 36‐fold) over standard ultrasonication or ball milling methods. The average diameter of the nanoparticles can be adjusted over the range 150–350 nm by appropriate adjustment of processing steps. If the fluid carrier in the microfluidizer contains an oxidant for Si, the resulting pSi particles are prepared with a core–shell structure, in which an elemental Si core is encased in a silicon oxide shell. When an aqueous sodium tetraborate processing solution is used, microfluidization generates photoluminescent core–shell pSi particles with a quantum yield of 19% in a single step in less than 20 min.
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