The relationship of leptin gene expression to adipocyte volume was investigated in lean 10-wk-old male C57BL/6J mice. mRNA levels for leptin, insulin receptor, glucocorticoid receptor, and tumor necrosis factor (TNF)-α in inguinal, epididymal, and retroperitoneal adipose tissues were quantified and related to adipocyte volume. Leptin mRNA levels were highly correlated with adipocyte volume within each fat depot. Multiple regression analysis of pooled data from the three depots showed that leptin mRNA levels were strongly correlated with adipocyte volumes (β = 0.84, P < 0.001) and, to a smaller degree, with glucocorticoid receptor mRNA levels (β = 0.36, P < 0.001). Depot of origin had no effect ( P > 0.9). Rates of leptin secretion in vitro were strongly correlated with leptin mRNA levels ( r = 0.89, P < 0.001). mRNA levels for TNF-α, insulin receptor, and glucocorticoid receptor showed no significant correlation with adipocyte volume. These results demonstrate that depot-specific differences in leptin gene expression are mainly related to the volumes of the constituent adipocytes. The strong correlation between leptin gene expression and adipocyte volume supports leptin's physiological role as a humoral signal of fat mass.

Two hairpin functionalized AuNRs were designed for NIR-laser triggered strand displacement amplification for microRNA quantitative analysis in single living cells.

No abstract

Highly efficient cellular transfection and intracellular signal amplification is a prerequisite for low-abundant microRNA (miRNA) imaging and biomedical application. Herein, we report a functional cancer cell membrane (CM) vesicle, Au–P/DSN@CM (DSN, double-specific nucleases), which consists of Au nanoparticles modified with three types of fluorescent miRNA detection probes (Au–P) and DSN that simultaneously encapsulate in cancer CM. We find that the Au–P/DSN@CM could specifically target the cancer cell and transfect the cell with higher efficiency than Au nanoparticles. The internalized Au–P/DSN@CM could further specifically recognize the target miRNA and induce DSN-assisted target recycle signal amplification, leading to multiple miRNA simultaneous detection with high sensitivity. It successfully detects oncogenic miRNAs in MCF-7 cells with high sensitivity and is amenable to monitor the dynamic expression change of oncogenic miRNAs in cancer cells. Our study represents a promising gene delivery vector for cancer diagnosis and potential therapy.