Search

Jae-Ho Jeon,1,* Somyoung Im,1,* Hyo Shin Kim,1 Dongyun Lee,1 Kwiwan Jeong,2 Jin-Mo Ku,2 Tae-Gyu Nam1 1Department of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University ERICA campus, Ansan, Gyeonggi-do, 15588, Republic of Korea; 2Gyeonggi Bio-Center, Gyeonggido Business and Science Accelerator, Suwon, Gyeonggi-do, 16229, Republic of Korea*These authors contributed equally to this workCorrespondence: Tae-Gyu Nam, Tel +82-31-400-5807, Fax +82-31-400-5958, Email tnam@hanyang.ac.krAbstract: The endoplasmic reticulum (ER) is responsible for structural transformation or folding of de novo proteins for transport to the Golgi. When the folding capacity of the ER is exceeded or excessive accumulation of misfolded proteins occurs, the ER enters a stressed condition (ER stress) and unfolded protein responses (UPR) are triggered in order to rescue cells from the stress. Recovery of ER proceeds toward either survival or cell apoptosis. ER stress is implicated in many pathologies, such as diabetes, cardiovascular diseases, inflammatory diseases, neurodegeneration, and lysosomal storage diseases. As a survival or adaptation mechanism, chaperone molecules are upregulated to manage ER stress. Chemical versions of chaperone have been developed in search of drug candidates for ER stress-related diseases. In this review, synthetic or semi-synthetic chemical chaperones are categorized according to potential therapeutic area and listed along with their chemical structure and activity. Although only a few chemical chaperones have been approved as pharmaceutical drugs, a dramatic increase in literatures over the recent decades indicates enormous amount of efforts paid by many researchers. The efforts warrant clearer understanding of ER stress and the related diseases and consequently will offer a promising drug discovery platform with chaperone activity.Keywords: endoplasmic reticulum stress, unfolded protein response, chemical chaperone, drug discovery, diabetes, cardiovascular disease, neurodegeneration, lysosomal storage disease

Abstract Background NADPH is used as a reductant in various biosynthetic reactions. Cell-free bio-systems have gained considerable attention owing to their high energy utilization and time efficiency. Efforts have been made to continuously supply reducing power to the reaction mixture in a cyclical manner. The thylakoid membrane (TM) is a promising molecular energy generator, producing NADPH under light. Thus, TM sustainability is of major relevance for its in vitro utilization. Results Over 70% of TMs prepared from Synechocystis sp. PCC6803 existed in a sealed vesicular structure, with the F1 complex of ATP synthase facing outward (right-side-out), producing NADPH and ATP under light. The NADPH generation activity of TM increased approximately two-fold with the addition of carbonyl cyanide-p-(trifluoromethoxy) phenylhydrazone (FCCP) or removal of the F1 complex using EDTA. Thus, the uncoupling of proton translocation from the electron transport chain or proton leakage through the Fo complex resulted in greater NADPH generation. Biosilicified TM retained more than 80% of its NADPH generation activity after a week at 30°C in the dark. However, activity declined sharply to below 30% after two days in light. The introduction of engineered water-forming NADPH oxidase (Noxm) to keep the electron transport chain of TM working resulted in the improved sustainability of NADPH generation activity in a ratio (Noxm to TM)-dependent manner, which correlated with the decrease of singlet oxygen generation. Removal of reactive oxygen species (ROS) by catalase further highlighted the sustainable NADPH generation activity of up to 80% in two days under light. Conclusion Reducing power generated by light energy has to be consumed for TM sustainability. Otherwise, TM can generate singlet oxygen, causing oxidative damage. Thus, TMs should be kept in the dark when not in use. Although NADPH generation activity by TM can be extended via silica encapsulation, further removal of hydrogen peroxide results in an improvement of TM sustainability. Therefore, as long as ROS formation by TM in light is properly handled, it can be used as a promising source of reducing power for in vitro biochemical reactions. Graphical Abstract

The production of phytylated chlorophyll a (Chl aP) in Rhodobacter sphaeroides, which uses phytylated bacteriochlorophyll a (BChl aP), is the first step in expanding the light absorption spectra. Unlike the chlorophyll synthase (ChlG) of the Synechocystis sp. PCC6803, ChlGs of angiosperms, including Arabidopsis thaliana, Nicotiana tabacum, Avena sativa, and Oryza sativa, showed bacteriochlorophyll synthase activity and resistance to inhibition by bacteriochlorophyllide a (BChlide a), geranylgeranylated BChl a (BChl aGG), and BChl aP, collectively called bacteriochlorins. Among the angiosperm ChlGs, N. tabacum ChlG had the highest bacteriochlorophyll synthase activity and resistance to inhibition by bacteriochlorins. Expression of N. tabacum chlG in R. sphaeroides resulted in the formation of free Chl aP in the presence of BChl aP during photoheterotrophic growth, even though reactive oxygen species were generated.

2-Oxoglutarate:ferredoxin oxidoreductase from Chlorobaculum tepidum (CtOGOR) is a carbon-fixing enzyme in the reductive TCA cycle that reversibly carboxylates succinyl-CoA to yield 2-oxoglutarate. CtOGOR is a heterotetramer of two large (α = 68 kDa) and two small (β = 38 kDa) subunits. The αβ protomer harbors one thiamine pyrophosphate and two 4Fe-4S clusters. Nonetheless, the enzyme has a considerable oxygen tolerance with a half-life of 143 min at 215 μM dissolved oxygen. Kinetic analyses of the purified recombinant CtOGOR revealed a lower Km for succinyl-CoA than for 2-oxoglutarate. Cellular levels of 2-oxoglutarate and glutamate—a product of glutamine oxoglutarate aminotransferase and glutamate dehydrogenase—increased more than twofold in the exponential phase compared with the control strain, leading to an approximately >30% increase in the photoautotrophic growth rate. Thus, CtOGOR was successfully produced in Synechocystis, thereby boosting carboxylation, resulting in enhanced photoautotrophic growth.

Perovskite solar cells have drawn much attention recently owing to their world-record-setting photovoltaic performances, whereas their practicality is still limited by the structural instability that often arises from ion migration and defect formation. Despite the general understanding that ion instability is a primary cause for degradation, there is no observation of structural transformation at the atomistic scale. Such observation is crucial to understand how instabilities are induced by external perturbations such as illumination or electrical bias, allowing researchers to devise effective strategies to mitigate them. Here, we designed an in situ transmission electron microscopy setup to enable real-time observation of amorphization in perovskite materials under electrical biasing. To reverse the device performance degradation due to such structural changes, the samples were heated at 50 °C and were found to recrystallize, effectively regaining their performance losses. This work presents vital insights on understanding ion-migration phenomena and addressing instability challenges of perovskite optoelectronics.

Introduction Singapore phased in standardized tobacco packaging on 1 July 2020 following a three-month grace period. This pre-post study evaluated its impacts on smoking-related behaviors and perceptions among adults who currently smoke. Methods Baseline and follow-up data were collected in a pre- and post-questionnaire from a cohort of 1873 Singaporean adults who were currently smoking at baseline. Baseline data were collected from December 2019 to May 2020, and followup data from July 2021 to September 2021. We used descriptive statistics and bivariate analyses to assess pre-post changes (Bhapkar’s test, Wilcoxon signed rank test) and to identify characteristics of participants who had quit or cut down smoking at follow-up (Pearson’s chi-squared, Fisher’s exact test). Results At follow-up, 11.7% (n=220) had quit smoking. There was a higher proportion of those smoking non-daily (pre: 13.1%, post: 16.9%; p

Abstract With the increase in the dependency on digital devices, the incidence of myopia, a precursor of various ocular diseases, has risen significantly. Because myopia and eyeball volume are related, myopia progression can be monitored through eyeball volume estimation. However, existing methods are limited because the eyeball shape is disregarded during estimation. We propose an automated eyeball volume estimation method from computed tomography images that incorporates prior knowledge of the actual eyeball shape. This study involves data preprocessing, image segmentation, and volume estimation steps, which include the truncated cone formula and integral equation. We obtained eyeball image masks using U-Net, HFCN, DeepLab v3 +, SegNet, and HardNet-MSEG. Data from 200 subjects were used for volume estimation, and manually extracted eyeball volumes were used for validation. U-Net outperformed among the segmentation models, and the proposed volume estimation method outperformed comparative methods on all evaluation metrics, with a correlation coefficient of 0.819, mean absolute error of 0.640, and mean squared error of 0.554. The proposed method surpasses existing methods, provides an accurate eyeball volume estimation for monitoring the progression of myopia, and could potentially aid in the diagnosis of ocular diseases. It could be extended to volume estimation of other ocular structures.

Abstract Intracellular membranes composing organelles of eukaryotes include membrane proteins playing crucial roles in physiological functions. However, a comprehensive understanding of the cellular responses triggered by intracellular membrane-focused oxidative stress remains elusive. Herein, we report an amphiphilic photocatalyst localised in intracellular membranes to damage membrane proteins oxidatively, resulting in non-canonical pyroptosis. Our developed photocatalysis generates hydroxyl radicals and hydrogen peroxides via water oxidation, which is accelerated under hypoxia. Single-molecule magnetic tweezers reveal that photocatalysis-induced oxidation markedly destabilised membrane protein folding. In cell environment, label-free quantification reveals that oxidative damage occurs primarily in membrane proteins related to protein quality control, thereby aggravating mitochondrial and endoplasmic reticulum stress and inducing lytic cell death. Notably, the photocatalysis activates non-canonical inflammasome caspases, resulting in gasdermin D cleavage to its pore-forming fragment and subsequent pyroptosis. These findings suggest that the oxidation of intracellular membrane proteins triggers non-canonical pyroptosis.

Objective We propose that cervical intrafacetal fusion (cIFF) using bone chip insertion into the facetal joint space additional to minimal PLF is a supplementary fusion method to conventional posterolateral fusion (PLF). Methods Patients who underwent posterior cervical fixation accompanied by cIFF with minimal PLF or conventional PLF for cervical myelopathy from 2012 to 2023 were investigated retrospectively. Radiological parameters including Cobb angle and C2–7 sagittal vertical axis (SVA) were compared between the 2 groups. In cIFF with minimal PLF group, cIFF location and PLF location were carefully divided, and the fusion rates of each location were analyzed by computed tomography scan. Results Among enrolled 46 patients, 31 patients were in cIFF group, 15 in PLF group. The postoperative change of Cobb angle in 1-year follow-up in cIFF with minimal PLF group and conventional PLF group were 0.1° ± 4.0° and -9.7° ± 8.4° respectively which was statistically lower in cIFF with minimal PLF group (p = 0.022). Regarding the fusion rate in cIFF with minimal PLF group in postoperative 6 months, the rates was achieved in 267 facets (98.1%) in cIFF location, and 244 facets (89.7%) in PLF location (p < 0.001). Conclusion Postoperative sagittal alignment was more preserved in cIFF with minimal PLF group compared with conventional PLF group. Additionally, in cIFF with minimal PLF group, the bone fusion rate of cIFF location was higher than PLF location. Considering the concerns of bone chip migration onto the spinal cord and relatively low fusion rate in PLF method, applying cIFF method using minimized PLF might be a beneficial alternative for posterior cervical decompression and fixation.

Abstract The synthesis of sequence-regulated oligosulfates has not yet been established due to the difficulties in precise reactivity control. In this work, we report an example of a multi-directional divergent iterative method to furnish oligosulfates based on a chain homologation approach, in which the fluorosulfate unit is regenerated. The oligosulfate sequences are determined by high resolution mass spectrometry of the hydrolyzed fragments, and polysulfate periodic copolymers are synthesized by using oligomeric bisfluorosulfates in a bi-directional fashion. The synthetic utility of this iterative ligation is demonstrated by preparing crosslinked network polymers as synthetic adhesive materials.

Introduction: Given the recent additions of immune checkpoint inhibitors (ICIs) to various cancer treatments, adverse effects, especially involving the eyes, have been on the rise. Here, we report an acute exacerbation of cancer-associated retinopathy (CAR) triggered by durvalumab treatment of small-cell lung cancer (SCLC). Case Presentation: An 81-year-old Asian male complained of a scotoma in the left eye after durvalumab administration, to treat SCLC. Humphrey visual field examination revealed a C-shaped temporal scotoma. Spectralis domain optical coherence tomography revealed outer retinal layer atrophy and progressive loss of the ellipsoid zone in the atrophic peripapillary area. Fundus autofluorescence (AF) images evidenced a large C-shaped hypo-AF with enhanced AF at the margin of the atrophic area, thus at the position of the scotoma. We prescribed subtenon triamcinolone injections under suspicion of CAR exacerbation, supported by positive Western blotting results for Rab6 and aldolase, and immunohistochemical staining of photoreceptor cells. The disrupted ellipsoid zone evident on OCT partially recovered, and a visual field test showed that the scotoma had improved. Conclusion: ICI-triggered exacerbation of CAR should be considered in SCLC patients before ICI treatment commences; an optimal treatment should preserve functional vision.