Kaempferol regulates apoptosis and migration of neural stem cells to attenuate cerebral infarction by O-GlcNAcylation of ß-catenin.

Ischemic stroke remains a major cause of disability and death. Kaempferol (Kae) is a neuroprotective flavonoid compound. Thus, this study aimed to explore the impact of Kae on cerebral infarction. We generated the middle cerebral artery occlusion (MCAO) mouse model to study the effects of Kae on infarction volume and neurological function. The oxygen and glucose deprivation (OGD)/reoxygenation (R) model of neural stem cells (NSCs) was established to study the effects of Kae on cell viability, migration, and apoptosis. Cell processes were assessed by cell counting kit-8, Transwell assay, flow cytometry, and TUNEL analysis. The molecular mechanism was assessed using the Western blot. The results indicated that Kae attenuated MCAO-induced cerebral infarction and neurological injury. Besides, Kae promoted cell viability and migration and inhibited apoptosis of OGD/R-treated NSCs. Moreover, OGD/R suppressed total O-GlcNAcylation level and O-GlcNAcylation of ß-catenin, thereby suppressing the Wnt/ß-catenin pathway, whereas Kae reversed the suppression. Inactivation of the Wnt/ß-catenin pathway abrogated the biological functions of NSCs mediated by Kae. In conclusion, Kae suppressed cerebral infarction by facilitating NSC viability, migration, and inhibiting apoptosis. Mechanically, Kae promoted O-GlcNAcylation of ß-catenin to activate the Wnt/ß-catenin pathway. Kae may have a lessening effect on ischemic stroke.

Transcranial ultrasound stimulation selectively affects cortical neurovascular coupling across neuronal types and LFP frequency bands.

Previous studies have affirmed that transcranial ultrasound stimulation (TUS) can influence cortical neurovascular coupling across low-frequency (0-2 Hz)/high-frequency (160-200 Hz) neural oscillations and hemodynamics. Nevertheless, the selectivity of this coupling triggered by transcranial ultrasound stimulation for spike activity (> 300 Hz) and additional frequency bands (4-150 Hz) remains elusive. We applied transcranial ultrasound stimulation to mice visual cortex while simultaneously recording total hemoglobin concentration, spike activity, and local field potentials. Our findings include (1) a significant increase in coupling strength between spike firing rates of putative inhibitory neurons/putative excitatory neurons and total hemoglobin concentration post-transcranial ultrasound stimulation; (2) an ~ 2.1-fold higher Pearson correlation coefficient between putative inhibitory neurons and total hemoglobin concentration compared with putative excitatory neurons and total hemoglobin concentration (*P < 0.05); (3) a notably greater cross-correlation between putative inhibitory neurons and total hemoglobin concentration than that between putative excitatory neurons and total hemoglobin concentration (*P < 0.05); (4) an enhancement of Pearson correlation coefficient between the relative power of γ frequency band (30-80 Hz), hγ frequency band (80-150 Hz) and total hemoglobin concentration following transcranial ultrasound stimulation (*P < 0.05); and (5) strongest cross-correlation observed at negative delay for θ frequency band, and positive delay for α, ß, γ, hγ frequency bands. Collectively, these results demonstrate that cortical neurovascular coupling evoked by transcranial ultrasound stimulation exhibits selectivity concerning neuronal types and local field potential frequency bands.

Synthesis of a novel 99mTc labeled GE11 peptide for EGFR SPECT imaging.

PURPOSE: This study investigated a novel SPECT agent for the noninvasive imaging of EGFR-overexpressing tumors. METHODS: The EGFR-targeting peptide GE11 was synthesized with the introduction of four amino acids (GGGC) to its C-terminal to act as a strong chelator and radiolabeled using 99mTc. The radiochemical yield of the 99mTc-peptide-GE11 were evaluated using RP-HPLC. Cellular assays of the probe were performed on two NSCLC cell lines: A549 (high expression) and H23 (low expression). Biodistribution and SPECT imaging were performed in BALB/c nude mice bearing A549 and H23 NSCLC xenografts. RESULTS: The 99mTc-peptide-GE11 was prepared at high efficiency with radiochemical yield of 98.40 ± 1.00 % and it showed favorable stability. The cellular uptake was significantly higher in A549 than in H23 at all time points (especially at 1 h, which was 10.34 ± 0.72 and 2.04 ± 0.18, respectively). A nearly 56% reduction in probe uptake was observed after pretreatment with excess unlabeled peptides. The performance of SPECT imaging and biodistribution demonstrated higher uptake of the 99mTc-peptide-GE11 in A549 xenograft than in H23 xenografts. CONCLUSION: The new SPECT tracer 99mTc-peptide-GE11 showed EGFR specificity, favorable pharmacokinetics and great potential for EGFR-targeted imaging.

In vivo imaging characterization and anticancer efficacy of a novel HER2 affibody and pemetrexed conjugate in lung cancer model.

INTRODUCTION: In this study, a new agent consisting of HER2-specific affibody ZHER2:V2 and chemotherapy drug pemetrexed was synthesized to develop a new targeted drug. Its biological characteristics and anticancer efficacy were assessed in cells level and xenografts models by radiolabeling with technetium-99m. METHODS: After the ZHER2:V2-pemetrexed conjugate was synthesized, radiolabeling of the conjugate was performed using its C-terminal 4 amino acids (Gly-Gly-Gly-Cys) as the chelating moiety. The radiochemical yield of the [99mTc]Tc-ZHER2:V2-pemetrexed was identified by instant thin-layer chromatography (ITLC). Stability of the radiolabeled conjugate was investigated both in vitro and in vivo. In vitro binding affinity and cell internalization study of the probe were performed in A549 cells (HER2-positive). Tumor uptake was evaluated by in vitro uptake assay in A549 cells and H23 cells (HER2-negative), and by in vivo biodistribution and SPECT imaging in A549 and H23 tumor-bearing mice. The antitumor efficacy of the ZHER2:V2-pemetrexed conjugate was evaluated in cells and xenograft models. RESULTS: The ZHER2:V2-pemetrexed was successfully synthesized and conjugated with technetium-99 m, and acquired the radiochemical yield of 97.0 ±â€¯0.3%. The stability of [99mTc]Tc-ZHER2:V2-pemetrexed was good in both physiological saline and human serum. The radiolabeled agent displayed excellent HER2-binding specificity and affinity in vitro, and was gradually internalized into the cells. Biodistribution study revealed obvious tumor uptake in A549 xenografts (percentage injected dose per gram, 2.6 ±â€¯1.0%ID/g at 4 h postinjection), while the uptake in HER2-negative H23 tumors was much lower (0.2 ±â€¯0.1%ID/g at 4 h postinjection, P < 0.01). SPECT imaging exhibited an intensity in the A549 xenograft which could be blocked by excess ZHER2:V2-pemetrexed. Treatment with ZHER2:V2-pemetrexed significantly impaired the tumor growth (P < 0.05), with less weight loss than pemetrexed. CONCLUSION: [99mTc]Tc-ZHER2:V2-pemetrexed showed desirable property and HER2-specificity. The ZHER2:V2-pemetrexed conjugate could inhibit tumor growth of HER2-positive lung adenocarcinoma and may have the potential to become a targeted drug for lung cancer. ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE: The compound described herein performs HER2-targeting with favorable anticancer efficacy and offers the potential of novel targeting strategies for further tumor therapy.

Anti-Inflammation of Natural Components from Medicinal Plants at Low Concentrations in Brain via Inhibiting Neutrophil Infiltration after Stroke.

Inflammation after stroke consists of activation of microglia/astrocytes in situ and infiltration of blood-borne leukocytes, resulting in brain damage and neurological deficits. Mounting data demonstrated that most natural components from medicinal plants had anti-inflammatory effects after ischemic stroke through inhibiting activation of resident microglia/astrocytes within ischemic area. However, it is speculated that this classical activity cannot account for the anti-inflammatory function of these natural components in the cerebral parenchyma, where they are detected at very low concentrations due to their poor membrane permeability and slight leakage of BBB. Could these drugs exert anti-inflammatory effects peripherally without being delivered across the BBB? Factually, ameliorating blood-borne neutrophil recruitment in peripheral circulatory system has been proved to reduce ischemic damage and improve outcomes. Thus, it is concluded that if drugs could achieve effective concentrations in the cerebral parenchyma, they can function via crippling resident microglia/astrocytes activation and inhibiting neutrophil infiltration, whereas the latter will be dominating when these drugs localize in the brain at a low concentration. In this review, the availability of some natural components crossing the BBB in stroke will be discussed, and how these drugs lead to improvements in stroke through inhibition of neutrophil rolling, adhesion, and transmigration will be illustrated.