Plasmid-encoding vasostatin inhibited the growth and metastasis of human hepatocellular carcinoma cells.

The growth and metastasis of solid tumors depends on angiogenesis. Anti-angiogenesis therapy may represent a promising therapeutic option. Vasostatin, the N-terminal domain of calreticulin, is a very potent endogenous inhibitor of angiogenesis and tumor growth. In this study, we attempted to investigate whether plasmid-encoding vasostatin complexed with cationic liposome could suppress the growth and metastasis of hepatocellular carcinoma in vivo and discover its possible mechanism of action. Apoptosis induction of pSecTag2B-vasostatin plasmid on murine endothelial cells (MS1) was examined by flow cytometric analysis in vitro. Nude mice bearing HCCLM3 tumor received pSecTag2B-vasostatin, pSecTag2B-Null, and 0.9 % NaCl solution, respectively. Tumor net weight was measured and survival time was observed. Microvessel density within tumor tissues was determined by CD31 immunohistochemistry. H&E staining of lungs and TUNEL assay of primary tumor tissues were also conducted. The results displayed that pSecTag2B-vasostatin could inhibit the growth and metastasis of hepatocellular carcinoma xenografts and prolong survival time compared with the controls in vivo. Moreover, histologic analysis revealed that pSecTag2B-vasostatin treatment increased apoptosis and inhibited angiogenesis. The present data may be of importance to the further exploration of this new anti-angiogenesis approach in the treatment of hepatocellular cancer.

PDMS-Parylene Hybrid, Flexible Micro-ECoG Electrode Array for Spatiotemporal Mapping of Epileptic Electrophysiological Activity from Multicortical Brain Regions.

Epilepsy detection and focus location are urgent issues that need to be solved in epilepsy research. A cortex conformable and fine spatial accuracy electrocorticogram (ECoG) sensor array, especially for real-time detection of multicortical functional regions and delineating epileptic focus remains a challenge. Here, we fabricated a polydimethylsiloxane (PDMS)-parylene hybrid, flexible micro-ECoG electrode array. The multiwalled carbon nanotubes (MWCNTs)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) nanocomposite-modified electrode interface significantly improved the sensing performance with low impedance (20.68 ± 6.65 kΩ), stable phase offset, and high sensitivity. The electrophysiological activities of multicortical brain regions (somatosensory cortex, parietal association cortex, and visual cortex) were simultaneously monitored during normal and epileptic statuses. The epileptic ECoG activities spread spatiotemporally from the starting point toward the adjacent cortex. Significant variations of the waveform, power, and frequency band were observed. The ECoG potential (123 ± 23 µV) at normal status was prominently up to 417 ± 87 µV at the spike wave stage. Besides, the power for epileptic activity (11.049 ± 4.513 µW) was 10 times higher than that (1.092 ± 0.369 µW) for normal activity. In addition, the theta frequency band was found to be a characteristic frequency band of epileptic signals. These joint analysis results of multicortical regions indicated that the active micron-scale region on the parietal association cortex was more likely to be the epileptogenic focus. Cortical mapping with high spatial detail provides the accurate delineation of lesions. The flexible micro-ECoG electrode array is a powerful tool for constructing a spatiotemporal map of the cortex. It provides a technical platform for epileptic focus location, biomedical diagnosis, and brain-computer interaction.

SWCNTs/PEDOT:PSS-Modified Microelectrode Arrays for Dual-Mode Detection of Electrophysiological Signals and Dopamine Concentration in the Striatum under Isoflurane Anesthesia.

Accurate detection of the degree of isoflurane anesthesia during a surgery is important to avoid the risk of overdose isoflurane anesthesia timely. To address this challenge, a four-shank implantable microelectrode array (MEA) was fabricated for the synchronous real-time detection of dual-mode signals [electrophysiological signal and dopamine (DA) concentration] in rat striatum. The SWCNTs/PEDOT:PSS nanocomposites were modified onto the MEAs, which significantly improved the electrical and electrochemical performances of the MEAs. The electrical performance of the modified MEAs with a low impedance (16.20 ± 1.68 kΩ) and a small phase delay (-27.76 ± 0.82°) enabled the MEAs to detect spike firing with a high signal-to-noise ratio (> 3). The electrochemical performance of the modified MEAs with a low oxidation potential (160 mV), a low detection limit (10 nM), high sensitivity (217 pA/µM), and a wide linear range (10 nM-72 µM) met the specific requirements for DA detection in vivo. The anesthetic effect of isoflurane was mediated by inhibiting the spike firing of D2_SPNs (spiny projection neurons expressing the D2-type DA receptor) and the broadband oscillation rhythm of the local field potential (LFP). Therefore, the spike firing rate of D2_SPNs and the power of LFP could reflect the degree of isoflurane anesthesia together. During the isoflurane anesthesia-induced death procedure, we found that electrophysiological activities and DA release were strongly inhibited, and changes in the DA concentration provided more details regarding this procedure. The dual-mode recording MEA provided a detection method for the degree of isoflurane anesthesia and a prediction method for fatal overdose isoflurane anesthesia.

CB1-Antibody Modified Liposomes for Targeted Modulation of Epileptiform Activities Synchronously Detected by Microelectrode Arrays.

Temporal lobe epilepsy (TLE) is a focal, recurrent, and refractory neurological disorder. Therefore, precisely targeted treatments for TLE are greatly needed. We designed anti-CB1 liposomes that can bind to CB1 receptors in the hippocampus to deliver photocaged compounds (ruthenium bipyridine triphenylphosphine γ-aminobutyric acid, RuBi-GABA) in the TLE rats. A 16-channel silicon microelectrode array (MEA) was implanted for simultaneously monitoring electrophysiological signals of neurons. The results showed that anti-CB1 liposomes were larger in size and remained in the hippocampus longer than unmodified liposomes. Following the blue light stimulation, the neural firing rates and the local field potentials of hippocampal neurons were significantly reduced. It is indicated that RuBi-GABA was enriched near hippocampal neurons due to anti-CB1 liposome delivery and photolyzed by optical stimulation, resulting dissociation of GABA to exert inhibitory actions. Furthermore, K-means cluster analysis revealed that the firing rates of interneurons were decreased to a greater extent than those of pyramidal neurons, which may have been a result of the uneven diffusion of RuBi-GABA due to liposomes binding to CB1. In this study, we developed a novel, targeted method to regulate neural electrophysiology in the hippocampus of the TLE rat using antibody-modified nanoliposomes, implantable MEA, and photocaged compounds. This method effectively suppressed hippocampal activities during seizure ictus with high spatiotemporal resolution, which is a crucial exploration of targeted therapy for epilepsy.