Pharmacological Inhibition of Spermine Oxidase Suppresses Excitotoxicity Induced Neuroinflammation in Mouse Retina

Polyamine oxidation plays a major role in neurodegenerative diseases. Previous studies from our laboratory demonstrated that spermine oxidase (SMOX, a member of the polyamine oxidase family) inhibition using MDL 72527 reduced neurodegeneration in models of retinal excitotoxicity and diabetic retinopathy. However, the mechanisms behind the neuroprotection offered by SMOX inhibition are not completely studied. Utilizing the experimental model of retinal excitotoxicity, the present study determined the impact of SMOX blockade in retinal neuroinflammation. Our results demonstrated upregulation in the number of cells positive for Iba-1 (ionized calcium-binding adaptor molecule 1), CD (Cluster Differentiation) 68, and CD16/32 in excitotoxicity-induced retinas, while MDL 72527 treatment reduced these changes, along with increases in the number of cells positive for Arginase1 and CD206. When retinal excitotoxicity upregulated several pro-inflammatory genes, MDL 72527 treatment reduced many of them and increased anti-inflammatory genes. Furthermore, SMOX inhibition upregulated antioxidant signaling (indicated by elevated Nrf2 and HO-1 levels) and reduced protein-conjugated acrolein in excitotoxic retinas. In vitro studies using C8-B4 cells showed changes in cellular morphology and increased reactive oxygen species formation in response to acrolein (a product of SMOX activity) treatment. Overall, our findings indicate that the inhibition SMOX pathway reduced neuroinflammation and upregulated antioxidant signaling in the retina.     

ICESat waveform-based land-cover classification using a curve matching approach

Light detection and ranging waveforms record the entire one-dimensional backscattered signal as a function of time within a footprint, which can potentially reflect the vertical structure information of the above-ground objects. This study aimed to explore the potential of the Geoscience Laser Altimeter System sensor on board the Ice, Cloud, and Land Elevation Satellite to perform land-cover classification by using only the profile curve of the full waveform. For this purpose, a curve matching method based on Kolmogorov–Smirnov (KS) distance was developed to measure the curve similarity between an unknown waveform and a reference waveform. A set of reference waveforms were first extracted from the training data set based on a principal component analysis (PCA). The unknown waveform was then compared with individual reference waveforms derived using KS distance and assigned to the class with the closest similarity. The results demonstrated that the KS distance-based land-cover classification using the waveform curve was able to achieve an overall accuracy of 87.2% and a kappa coefficient of 0.80. It outperformed the widely adopted rule-based method using Gaussian decomposition parameters by 3.5%. The research also indicated that the PCA- selected reference waveforms achieved substantially better results than randomly selected reference waveforms.     

4D Printing of Seed Capsule-Inspired Hygro-Responsive Structures via Liquid Crystal Templating-Assisted Vat Photopolymerization (Adv. Funct. Mater. 5/2023)

The creatures in nature exhibit dynamic responses to environmental stimuli through their hierarchical architectures. Benefiting from gradient porous structures, Delosperma nakurense opens its protective valves of the seed capsules when hydrated with liquid water, increasing the likelihood that seeds are dispersed under conditions favorable to germination. Here, a versatile 4D printing technology, namely liquid crystal templating-assisted vat photopolymerization (LCT-VPP), which can fabricate bioinspired porous structures with hygro-responsive capabilities by utilizing photopolymerization induced phase separation (PIPS) and liquid crystals (LCs) electro-alignment is reported. PIPS within the LCs/nanofiller composites leads to the formation of submicrometer gradient porous structures after extracting nonreactive LCs. The electric field enables the programmable alignment of LCs, which in turn elongates the porous structures and aligns nanofillers. In addition, the programmable arranged nanofillers by the templated LCs enhance the degree of deformation and thus the resulting composites exhibit high shape control accuracy, fast dynamic response, and high reliability. This study opens a perspective for designing bioinspired smart materials with the special spatial distribution of porous structures. The results reported here can give rise to various potential applications in soft robots, smart anticounterfeiting devices, flexible sensors, and ultrafiltration membrane.