The liver-to-spleen ratio is a risk factor predicting oxygen demand in COVID-19 patients.

Background: We aimed to investigate risk factors predicting oxygen demand in COVID-19 patients. Methods: Patients admitted to Shizuoka General Hospital with COVID-19 from August 2020 to August 2021 were included. First, we divided patients into groups with and without oxygen demand. Then, we compared patients' clinical characteristics and laboratory and radiological findings to determine factors predicting oxygen demand. Results: One hundred seventy patients with COVID-19 (aged 58±15 years, 57 females) were enrolled. Common comorbidities were cardiovascular diseases (47.6%), diabetes mellitus (28.8%), and dyslipidemia (26.5%). Elder age, higher body mass index, cardiovascular diseases, diabetes mellitus, lower lymphocyte count, albumin, hepatic attenuation value, and the liver-to-spleen ratio (L/S), higher D-dimer, aspartate aminotransferase, lactate dehydrogenase, troponin-T, C-reactive protein, KL-6, chest and abdominal circumference, and visceral fat were found in patients with oxygen demand. According to the multivariate logistic regression analysis, L/S, lymphocyte count, D-dimer, and abdominal circumference under the diaphragm were independent risk factors predicting oxygen demand in COVID-19 patients. Conclusions: On admission, L/S, lymphocyte count, D-dimer, and abdominal circumference were predictive factors for oxygen demand. These factors may help in the appropriate triage of COVID-19 patients in the decision to admit them to the hospital.

Structural Dissection of Epsin-1 N-Terminal Helical Peptide: The Role of Hydrophobic Residues in Modulating Membrane Curvature.

Spatiotemporal structural alterations in cellular membranes are the hallmark of many vital processes. In these cellular events, the induction of local changes in membrane curvature often plays a pivotal role. Many amphiphilic peptides are able to modulate membrane curvature, but there is little information on specific structural factors that direct the curvature change. Epsin-1 is a representative protein thought to initiate invagination of the plasma membrane upon clathrin-coated vesicles formation. Its N-terminal helical segment (EpN18) plays a key role in inducing positive membrane curvature. This study aimed to elucidate the essential structural features of EpN18 in order to better understand general curvature-inducing mechanisms, and to design effective tools for rationally controlling membrane curvature. Structural dissection of peptides derived from EpN18 revealed the decisive contribution of hydrophobic residues to (i) enhancing membrane interactions, (ii) helix structuring, (iii) inducing positive membrane curvature, and (iv) loosening lipid packing. The strongest effect was obtained by substitution with leucine residues, as this EpN18 analog showed a marked ability to promote the influx of octa-arginine cell-penetrating peptides into living cells.

Piezo1 activation using Yoda1 inhibits macropinocytosis in A431 human epidermoid carcinoma cells.

Macropinocytosis is a type of endocytosis accompanied by actin rearrangement-driven membrane deformation, such as lamellipodia formation and membrane ruffling, followed by the formation of large vesicles, macropinosomes. Ras-transformed cancer cells efficiently acquire exogenous amino acids for their survival through macropinocytosis. Thus, inhibition of macropinocytosis is a promising strategy for cancer therapy. To date, few specific agents that inhibit macropinocytosis have been developed. Here, focusing on the mechanosensitive ion channel Piezo1, we found that Yoda1, a Piezo1 agonist, potently inhibits macropinocytosis induced by epidermal growth factor (EGF). The inhibition of ruffle formation by Yoda1 was dependent on the extracellular Ca2+ influx through Piezo1 and on the activation of the calcium-activated potassium channel KCa3.1. This suggests that Ca2+ ions can regulate EGF-stimulated macropinocytosis. We propose the potential for macropinocytosis inhibition through the regulation of a mechanosensitive channel activity using chemical tools.

Blood eosinophil count and FeNO to predict benralizumab effectiveness in real-life severe asthma patients.

OBJECTIVE: Benralizumab is a promising drug for severe uncontrolled asthma. This study aimed to clarify the effectiveness of benralizumab in a real-life setting. METHODS: Subjects included 24 patients with severe type 2 asthma who received benralizumab between April 2018 and July 2019. Changes in parameters, exacerbation frequency, and oral corticosteroid (OCS) use after 4 and 24 weeks of administration were examined. The parameters included the Global Evaluation of Treatment Effectiveness (GETE) scale, Asthma Control Questionnaire (ACQ), Asthma Control Test (ACT), blood eosinophils, fractional exhaled nitric oxide (FeNO), and spirometry. The response to treatment was defined as follows: for patients with exacerbations or OCS use before treatment initiation, a reduction of ≥50% in exacerbation frequency or OCS use; and for patients without exacerbations or OCS use, an improvement of ≥0.5 in ACQ scores and ≥3 in ACT scores, or of ≥10.38% in FEV1. RESULTS: Twenty-one patients completed the treatment for 24 weeks. Excellent and good GETE scales and ACQ and ACT improvement were found in 67% of the patients at 4 weeks, and the effect continued until 24 weeks. The patients' rate with exacerbations was significantly reduced compared to the previous 24 weeks before administration. In 17 patients receiving OCS, the use could be reduced or quit in 14 patients. Overall, 16 patients (76.2%) met the responder definition and could be predicted by the baseline eosinophil count and FeNO levels with the best cutoff values of 100/µL and 40 ppb, respectively. CONCLUSIONS: Blood eosinophil and FeNO could predict benralizumab effectiveness.

Membrane anchoring of a curvature-inducing peptide, EpN18, promotes membrane translocation of octaarginine.

EpN18 is a curvature-inducing peptide, which loosens lipid packing upon interaction with the cell membrane, and facilitates cell-membrane penetration by arginine-rich cell-penetrating peptides, including octaarginine (R8). In the present study, we conjugated the N-terminal of EpN18 with a pyrenebutyryl (pBu) moiety, which acts as an anchoring unit that increases membrane interactions. Enhanced lipid-packing loosening and cytosolic translocation of R8 were observed by the pBu anchoring of EpN18.

Effectiveness of a 23-valent pneumococcal polysaccharide vaccine for the prevention of pneumococcal pneumonia in the elderly with chronic respiratory diseases: a case-control study of a single center.

BACKGROUND: The effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) in preventing pneumococcal pneumonia has been controversial. METHODS: To evaluate the effectiveness of the PPSV23 in elderly outpatients with chronic respiratory diseases, we carried out a case-control study, including 4128 outpatients aged ≥ 65 years, in the respiratory department. RESULTS: There were 320 vaccinated patients, of which 164 were diagnosed with pneumococcal pneumonia. The adjusted odds ratio was 0.39 (95% confidence interval (CI), 0.17 to 0.89). In the subsets consisting of age groups ≥ 70 and ≥ 75 years, the adjusted odds ratio (95% CI) was respectively 0.16 (0.04 to 0.67) and 0.15 (0.02 to 1.12). CONCLUSION: This real-world study suggests that PPSV23 can be useful in preventing pneumococcal pneumonia in the elderly with chronic respiratory diseases.

An Artificial Amphiphilic Peptide Promotes Endocytic Uptake by Inducing Membrane Curvature.

Membrane curvature plays a pivotal role in cellular life, including cellular uptake and membrane trafficking. The modulation of membrane curvature provides a novel means of manipulating cellular events. In this report, we show that a nine-residue amphiphilic peptide (R6W3) stimulates endocytic uptake by inducing membrane curvature. Curvature formation on cell membranes was confirmed by observing the cellular distribution of the curvature-sensing protein amphiphysin fused with a yellow fluorescent protein (Amp-YFP). Dot-like signals of Amp-YFP were visible following the addition of R6W3, suggesting curvature formation in cell membranes, leading to endocytic cup and vesicle formation. The promotion of endocytic uptake was confirmed using the endocytosis marker polydextran. Treatment of cells with R6W3 yielded a 4-fold dextran uptake compared with untreated cells. The amphiphilic helical structure of R6W3 was also crucial for R6W3-stimulated endocytic uptake.

Enhancing the activity of membrane remodeling epsin-peptide by trimerization.

Modulating the structural dynamics of biomembranes by inducing bilayer curvature and lipid packing defects has been highlighted as a practical tool to modify membrane-dependent cellular processes. Previously, we have reported on an amphipathic helical peptide derived from the N-terminal segment (residues 1-18, EpN18) of epsin-1, which can promote membrane remodeling including lipid packing defects in cell membranes. However, a high concentration is required to exhibit a pronounced effect. In this study, we demonstrate a significant increase in the membrane-remodeling effect of EpN18 by constructing a branched EpN18 homotrimer. Both monomer and trimer could enhance cell internalization of octaarginine (R8), a cell-penetrating peptide. The EpN18 trimer, however, promoted the uptake of R8 at an 80-fold lower concentration than the monomer. Analysis of the generalized polarization of a polarity-sensitive dye (di-4-ANEPPDHQ) revealed a higher efficacy of trimeric EpN18 in loosening the lipid packing in the cell membrane. Circular dichroism measurements in the presence of lipid vesicles showed that the EpN18 trimer has a higher α-helix content compared with the monomer. The stronger ability of the EpN18 trimer to impede negative bilayer curvature is also corroborated by solid-state 31P NMR spectroscopy. Hence, trimerizing peptides can be considered a promising approach for an exponential enhancement of their membrane-remodeling performance.

Development of a Membrane Curvature-Sensing Peptide Based on a Structure-Activity Correlation Study.

Membrane curvature formation is important for various biological processes such as cell motility, intracellular signal transmission, and cellular uptake of foreign substances. However, it remains still a challenging topic to visualize the membrane curvature formation on the cell membranes in real-time imaging. To develop and design membrane curvature-sensors, we focused on amphipathic helical peptides of proteins belonging to the Bin/Amphiphysin/Rvs (BAR) family as the starting point. BAR proteins individually have various characteristic structures that recognize different curvatures, and the derived peptides possess the potential to function as curvature sensors with a variety of recognition abilities. Peptide-based curvature sensors can have wide applications in biological research fields due to their small size, easy modification, and large production capability in comparison to protein-based sensors. In the present study, we found that an amphipathic peptide derived from sorting nexin1 (SNX1) has a curvature-recognition ability. The mutation studies of the initial peptide revealed a close correlation between the α-helicity and lipid binding ability of the peptides. In particular, the amino acids located on the hydrophobic face played a vital role in curvature recognition. The α-helix formation of the peptides was thought to serve to accommodate lipid-packing defects on the membrane surface and to maintain their binding to lipid vesicles. The structure-activity correlation found in this study have the potential to contribute to the design of peptide-based curvature sensors that will enable the capture of various life phenomena in cells.

An influenza-derived membrane tension-modulating peptide regulates cell movement and morphology via actin remodeling.

Tension in cell membranes is closely related to various cellular events, including cell movement and morphogenesis. Therefore, modulation of membrane tension can be a new approach for manipulating cellular events. Here, we show that an amphipathic peptide derived from the influenza M2 protein (M2[45-62]) yields lamellipodia at multiple sites in the cell. Effect of M2[45-62] on cell membrane tension was evaluated by optical tweezer. The membrane tension sensor protein FBP17 was involved in M2[45-62]-driven lamellipodium formation. Lysine-to-arginine substitution in M2[45-62] further enhanced its activity of lamellipodium formation. M2[45-62] had an ability to reduce cell motility, evaluated by scratch wound migration and transwell migration assays. An increase in neurite outgrowth was also observed after treatment with M2[45-62]. The above results suggest the potential of M2[45-62] to modulate cell movement and morphology by modulating cell membrane tension.

Metastatic pulmonary malignant melanoma showing a ring-shaped and halo signs.

Classically, metastatic tumours are solid, multiple, well-circumscribed, and rarely cavitary. This rare case of metastatic pulmonary malignant melanoma showed a ring-shaped ground-glass opacity and then the halo sign, depending on the disease progression.

Importance of Net Hydrophobicity in the Cellular Uptake of All-Hydrocarbon Stapled Peptides.

All-hydrocarbon stapled peptides make up a promising class of protein-protein interaction regulators; their potential therapeutic benefit arises because they have a high binding affinity and specificity for intracellular molecules. The cell permeation efficacy of these peptides is a critical determinant of their bioactivity. However, the factors that determine their cellular uptake remain an active area of research. In this study, we evaluated the effect of stapled (or cross-linked) formation on the cellular uptake of six known all-hydrocarbon stapled peptides. We found that the rate of cellular uptake of unstapled peptides (i.e., those bearing olefinic non-natural amino acids that are not subjected to olefin metathesis) was higher than that for the corresponding stapled peptides. Additionally, the insertion of these olefinic non-natural amino acids into peptide sequences significantly increased their rate of cellular uptake. According to the high-performance liquid chromatography retention times, the overall hydrophobicity of unstapled peptides was greater than that of stapled peptides, followed by that of the original peptides without olefinic non-natural amino acids. There was not a close correlation between helical content and the rate of cellular uptake of these peptides. Therefore, the increase in overall hydrophobicity resulting from the introduction of non-natural amino acids, rather than the structural stabilization resulting from staple formation, is the key driver promoting cellular uptake. Macropinocytosis, a form of fluid-phase endocytosis, was involved in the cellular uptake of all six peptides.

Loosening of Lipid Packing Promotes Oligoarginine Entry into Cells.

Despite extensive use of arginine-rich cell-penetrating peptides (CPPs)-including octaarginine (R8)-as intracellular delivery vectors, mechanisms for their internalization are still under debate. Lipid packing in live cell membranes was characterized using a polarity-sensitive dye (di-4-ANEPPDHQ), and evaluated in terms of generalized polarization. Treatment with membrane curvature-inducing peptides led to significant loosening of the lipid packing, resulting in an enhanced R8 penetration. Pyrenebutyrate (PyB) is known to facilitate R8 membrane translocation by working as a hydrophobic counteranion. Interestingly, PyB also actively induced membrane curvature and perturbed lipid packing. R8 is known to directly cross cell membranes at elevated concentrations. The sites of R8 influx were found to have looser lipid packing than surrounding areas. Lipid packing loosening is proposed as a key factor that governs the membrane translocation of CPPs.