Association of Hydrophobic Carboxyl-Terminal Dendrimers with Lymph Node-Resident Lymphocytes.

Delivery systems to lymph node-resident T cells around tumor tissues are essential for cancer immunotherapy, in order to boost the immune responses. We previously reported that anionic dendrimers, such as carboxyl-, sulfonyl-, and phosphate-terminal dendrimers, were efficiently accumulated in lymph nodes via the intradermal injection. Depending on the terminal structure, their cell association properties were different, and the carboxyl-terminal dendrimers did not associate with any immune cells majorly. In this study, we investigated the delivery of carboxyl-terminal dendrimers with different hydrophobicity to lymph node-resident lymphocytes. Four types of carboxyl-terminal dendrimers-succinylated (C) and 2-carboxy-cyclohexanoylated (Chex) dendrimers with and without phenylalanine (Phe)-were synthesized and named C-den, C-Phe-den, Chex-den, and Chex-Phe-den, respectively. Chex-Phe-den was well associated with lymphocytes, but others were not. Chex-Phe-den, intradermally injected at the footpads of mice, was accumulated in the lymph node, and was highly associated with the lymphocytes, including T cells. Our results suggest that Chex-Phe-den has the potential for delivery to the lymph node-resident T cells, without any specific T cell-targeted ligands.

Carboxyl-, sulfonyl-, and phosphate-terminal dendrimers as a nanoplatform with lymph node targeting.

The development of drug delivery vehicles to cancer and/or immune cells in lymph nodes is important for cancer diagnosis, therapy, and immunotherapy. We previously reported that anionic carboxyl-terminal dendrimers were accumulated in lymph nodes. In this study, three anionic dendrimers with carboxyl-, sulfonyl-, and phosphate-terminal groups were prepared to examine the lymph node targeting and the association with immune cells in the lymph nodes. These anionic dendrimers were accumulated in the lymph node by intradermal injection. Although the carboxyl- and sulfonyl-terminal dendrimers were diffused from the injection site, the phosphate-terminal dendrimers were mostly retained. The phosphate-terminal dendrimer was recognized by the macrophages, dendritic cells, and B cells in the lymph node, whereas the carboxyl- and sulfonyl-terminal dendrimers were not. Our results show that these anionic dendrimers were accumulated in the lymph node where the association with immune cells could be controlled by the terminal structure of the dendrimer. The phosphate-terminal dendrimer can be used as a nanoplatform for the delivery of some bioactive molecules to some immune cells, including B cells, in the lymph node.

Distinct association of serum FGF21 or adiponectin levels with clinical parameters in patients with type 2 diabetes.

Fibroblast growth factor 21 (FGF21) has been identified as a novel metabolic regulator. This cross-sectional study was performed to clarify how serum FGF21 levels were associated with clinical parameters in Japanese subjects with type 2 diabetes (n=139). Anthropometric and blood biochemical parameters, uses of drugs for diabetes, hypertension and dyslipidemia were examined regarding associations with fasting serum FGF21 concentrations. FGF21 levels were 6-times higher in those subjects taking fibrates. However, a use of thiazolidinediones did not affect serum FGF21 levels while it induced higher serum adiponectin levels. In univariate analyses, FGF21 levels showed associations with a use of fibrates, triglyceride levels, creatinine levels, waist circumference, and BMI. Multiple regression analyses adjusted for age, gender and BMI showed that a use of fibrates, triglyceride levels and creatinine levels were strong contributors to serum FGF21 levels. In contrast, a use of thiazolidinediones, HDL-cholesterol levels and fasting insulin levels were strong contributors to serum adiponectin levels. This study revealed that serum FGF21 levels were biochemical indicators correlating to a set of essential metabolic parameters, which was distinct from that correlating to serum adiponectin levels in subjects with type 2 diabetes.

Induction of ABCA1 by overexpression of hormone-sensitive lipase in macrophages.

Initial step toward the reverse-cholesterol transport is cholesterol efflux that is mediated by the ATP-binding cassette transporter A1 (ABCA1). However, it is unknown how the cholesteryl ester (CE) hydrolysis induces the expression of the ABCA1 gene. Overexpression of hormone-sensitive lipase (HSL) increased the hydrolysis of CE and stimulated the expression of ABCA1 gene at the transcriptional level in RAW 264.7 macrophages. The stimulatory effects of the HSL overexpression and cholesterol loading on the ABCA1 promoter activity were additive. Mutational analyses of the promoter of ABCA1 identified the responsible element as the direct repeat-4 (DR-4) that binds LXR/RXR heterodimers. In conclusion, stimulation of hydrolysis of CE in macrophages induces the expression of ABCA1 gene primarily via the LXR-dependent pathway and can be useful for the prevention of atherosclerosis.

Cholesterol reduction and atherosclerosis inhibition by bezafibrate in low-density lipoprotein receptor knockout mice.

Fibrates, peroxisome proliferator-activated receptor a agonists, are widely used as lipid-lowering agents with anti-atherogenic activity. However, conflicting results have been reported with regard to their pharmacological effects on plasma lipoprotein profiles as well as on atherosclerosis in animal models. Furthermore, the anti-atherogenic effects of bezafibrate, one of the most commonly used fibrates, in animal models have not been reported. In the present study, we investigated the effects of bezafibrate on lipoprotein profiles as well as on atherosclerosis in low-density lipoprotein receptor knockout (LDLR-/-) mice fed an atherogenic diet for 8 weeks. Bezafibrate decreased plasma levels of both cholesterol and triglycerides (TG), while increasing plasma levels of high-density lipoprotein-cholesterol (HDL-C). Since hepatic TG production was significantly reduced in the bezafibrate-treated mice lacking LDLR, the plasma lipid-lowering effects of bezafibrate might be primarily mediated by the suppression of hepatic production of apolipoprotein-B-containing lipoproteins. In parallel with the reduced ratio of non-HDL-C to HDL-C, bezafibrate suppressed fatty streak lesions in the aortic sinus by 51%. To determine whether or not bezafibrate directly alters the expression of genes relevant to atherosclerosis, we measured mRNA expression levels of three genes in the aorta by real-time PCR: ATP-binding cassette transporter A1, lipoprotein lipase, and monocyte chemoattractant protein-1. The results showed that there were no differences in the expression of these genes between mice treated with bezafibrate and those not. In conclusion, bezafibrate inhibits atherosclerosis in LDLR-/- mice primarily by decreasing the ratio of non-HDL-C to HDL-C.