Cardiac dysfunction is a major consequence of septic shock and may be responsible for the high mortality of sepsis. We have reported that transgenic mice with cardiac-specific overexpression of heat shock protein 27 (Hsp27 Tg) exhibited the protection against doxorubicin-induced cardiac dysfunction. We hypothesized that overexpression of Hsp27 will attenuate cardiac dysfunction during endotoxemia. Hsp27 Tg and age-matched wild-type (WT) mice were injected with LPS. Cardiac function was evaluated by echocardiography, survival rate was carefully monitored, and activities of signaling pathways were determined by immunoblot. LPS administration significantly decreased cardiac function in WT mice. In Hsp27 Tg mice, LPS-induced cardiac dysfunction was significantly attenuated as evidenced by increased ejection fraction (27.3%) and fractional shortening (37.1%), respectively, compared with LPS-treated WT mice. Heat shock protein 27 Tg mice were more resistant to LPS-induced mortality than WT. The levels of phospho-Akt and phospho-glycogen synthase kinase 3beta (phospho-GSK-3beta) in the myocardium were significantly increased in Hsp27 Tg mice compared with WT after LPS administration. Nuclear factor kappaB-binding activity was significantly decreased in Hsp27 Tg mice compared with WT mice after LPS challenge. Similar results were observed in in vitro studies using Hsp27-transfected rat cardiomyoblasts. Importantly, phosphoinositide 3-kinase inhibition abolished the protective effect of Hsp27 in LPS-induced cardiac dysfunction and mortality of endotoxemia. Our results suggest that Hsp27 plays an important role in attenuation of cardiac dysfunction and mortality in endotoxemia and that the mechanisms of the protection may involve activation of the PI3K/Akt signaling pathway.

Diabetes is an independent risk factor for vertebral fracture, primarily being due to diabetic osteoporosis.

Importin 13 is a member of the importin beta superfamily of nuclear transport proteins and is expressed in multiple tissues at high levels both in humans and rodents, including fetal lung, brain, and heart. In order to elucidate potential functions of imp13 in the heart, we have used rat imp13 as bait to screen a human heart cDNA library and identified an interaction with the C-terminal peptide of myopodin (a.a. 360-698), an actin-bundling protein, associated with tumor-suppressor activity that localizes to both the cytoplasm and the nucleus. We have used GST-pull down assays and co-immunoprecipitation experiments to demonstrate an interaction between imp13 and full-length myopodin and observed that RanGTP dissociates the myopodin-imp13 complex. In studies of cultured cells, we show that both imp13 siRNA and a C-terminal fragment of imp13 protein prevent nuclear localization of myopodin. We, therefore, conclude that imp13 functions in myopodin import and we suggest that the regulation of these events is critical for normal and abnormal cellular differentiation.

Baicalin (BAI), one major flavonoid from Scutellaria baicalensis, possesses anticancer and anti-inflammatory properties. However, the effect of BAI on diabetes mellitus has not been investigated. This study explored the antidiabetic effect of BAI on pancreatic β-cell line Min6. Min6 cells were treated with tumor necrosis factor-α (TNF-α) to mimic β-cell destruction in type 1 diabetes mellitus. The effects of BAI on viability and apoptosis of Min6 cells were analyzed by the cell counting kit-8 assay and Annexin V-fluoresceine isothiocyanate/propidium iodide staining method. The insulin secretion of Min6 cells was determined using radioimmunoassay. Expression of apoptosis-associated proteins and inducible nitric oxide synthase (iNOS), and activation of phosphatidylinositol 3'-kinase/protein kinase B (PI3K/AKT) and nuclear factor ΚB (NF-κB) pathways were analyzed by Western blot analysis. Relative microRNA-205 (miR-205) expression was determined by quantitative real time polymerase chain reaction. TNF-α treatment inhibited cell growth and insulin secretion, but promoted iNOS expression. All of these effects were reversed by BAI treatment. BAI promoted viability; suppressed apoptosis; regulated caspase-3, B-cell lymphoma 2 and Bcl-2-associated X protein; decreased iNOS level; and increased insulin production. BAI protected Min6 cells by upregulating miR-205. Besides, the Min6 cell-protective effect of BAI was PI3K/AKT pathway and NF-κB pathway dependent. BAI activated the PI3K/AKT pathway and inhibited the NF-κB pathway by regulating miR-205. In conclusion, BAI protected Min6 cells from TNF-α-induced injury by upregulating miR-205, which acts, at least in part, via activation of the PI3K/AKT pathway and inactivation of the NF-κB pathway.