L-Type Calcium Channel Modulates Low-Intensity Pulsed Ultrasound-Induced Excitation in Cultured Hippocampal Neurons.

As a noninvasive technique, ultrasound stimulation is known to modulate neuronal activity both in vitro and in vivo. The latest explanation of this phenomenon is that the acoustic wave can activate the ion channels and further impact the electrophysiological properties of targeted neurons. However, the underlying mechanism of low-intensity pulsed ultrasound (LIPUS)-induced neuro-modulation effects is still unclear. Here, we characterize the excitatory effects of LIPUS on spontaneous activity and the intracellular Ca2+ homeostasis in cultured hippocampal neurons. By whole-cell patch clamp recording, we found that 15 min of 1-MHz LIPUS boosts the frequency of both spontaneous action potentials and spontaneous excitatory synaptic currents (sEPSCs) and also increases the amplitude of sEPSCs in hippocampal neurons. This phenomenon lasts for > 10 min after LIPUS exposure. Together with Ca2+ imaging, we clarified that LIPUS increases the [Ca2+]cyto level by facilitating L-type Ca2+ channels (LTCCs). In addition, due to the [Ca2+]cyto elevation by LIPUS exposure, the Ca2+-dependent CaMKII-CREB pathway can be activated within 30 min to further regulate the gene transcription and protein expression. Our work suggests that LIPUS regulates neuronal activity in a Ca2+-dependent manner via LTCCs. This may also explain the multi-activation effects of LIPUS beyond neurons. LIPUS stimulation potentiates spontaneous neuronal activity by increasing Ca2+ influx.

FNDC5 attenuates obesity-induced cardiac hypertrophy by inactivating JAK2/STAT3-associated inflammation and oxidative stress.

BACKGROUND: Chronic low-grade inflammation and oxidative stress play important roles in the development of obesity-induced cardiac hypertrophy. Here, we investigated the role of Fibronectin type III domain containing 5 (FNDC5) in cardiac inflammation and oxidative stress in obesity-induced cardiac hypertrophy. METHODS: Male wild-type and FNDC5-/- mice were fed normal chow or high fat diet (HFD) for 20 weeks to induce obesity, and primary cardiomyocytes and H9c2 cells treated with palmitate (PA) were used as in vitro model. The therapeutic effects of lentiviral vector-mediated FNDC5 overexpression were also examined in HFD-induced cardiac hypertrophy. RESULTS: High fat diet manifested significant increases in body weight and cardiac hypertrophy marker genes expression, while FNDC5 deficiency aggravated cardiac hypertrophy evidenced by increased Nppa, Nppb and Myh7 mRNA level and cardiomyocytes area, in association with enhanced cardiac inflammatory cytokines expression, oxidative stress level and JAK2/STAT3 activation in HFD-fed mice. FNDC5 deficiency in primary cardiomyocytes or FNDC5 knockdown in H9c2 cells enhanced PA-induced inflammatory responses and NOX4 expression. Exogenous FNDC5 pretreatment attenuated PA-induced cardiomyocytes hypertrophy, inflammatory cytokines up-regulation and oxidative stress in primary cardiomyocytes and H9c2 cells. FNDC5 overexpression attenuated cardiac hypertrophy as well as cardiac inflammation and oxidative stress in HFD-fed mice. CONCLUSIONS: FNDC5 attenuates obesity-induced cardiac hypertrophy by inactivating JAK2/STAT3 associated-cardiac inflammation and oxidative stress. The cardio-protective role of FNDC5 shed light on future therapeutic interventions in obesity and related cardiovascular complications.

[Investigation of the temperature-dependent spectral characteristics of colloidal PbSe nanocrystals].

In the present paper colloidal PbSe nanocrystals were prepared with the particle size of 3.8 and 5.8 nm, and the temperature- dependent optical properties of colloidal PbSe nanocrystals were investigated. The experimental data show that the band gap, photoluminescence peak wavelength, photoluminescence intensity and full width at half-maximum of colloidal PbSe nanocrystals will change with variations in temperature and size at room temperature. The band gap of colloidal PbSe nanocrystals with the particle size of 3.8 nm shifts towards red when the temperature increases. However, the blue shift occurs when the particle size is 5.8 nm. The photoluminescence intensity of colloidal PbSe nanocrystals drops and the full width at half-maximum will increases with the increase in temperature.