Establishment of multicenter COVID-19 therapeutics preclinical test system in Republic of Korea.

Throughout the recent COVID-19 pandemic, South Korea led national efforts to develop vaccines and therapeutics for SARS-CoV-2. The project proceeded as follows: 1) evaluation system setup (including Animal Biosafety Level 3 (ABSL3) facility alliance, standardized nonclinical evaluation protocol, and laboratory information management system), 2) application (including committee review and selection), and 3) evaluation (including expert judgment and reporting). After receiving 101 applications, the selection committee reviewed pharmacokinetics, toxicity, and efficacy data and selected 32 final candidates. In the nonclinical efficacy test, we used golden Syrian hamsters and human angiotensin-converting enzyme 2 transgenic mice under a cytokeratin 18 promoter to evaluate mortality, clinical signs, body weight, viral titer, neutralizing antibody presence, and histopathology. These data indicated eight new drugs and one repositioned drug having significant efficacy for COVID-19. Three vaccine and four antiviral drugs exerted significant protective activities against SARS-CoV-2 pathogenesis. Additionally, two anti-inflammatory drugs showed therapeutic effects on lung lesions and weight loss through their mechanism of action but did not affect viral replication. Along with systematic verification of COVID-19 animal models through large-scale studies, our findings suggest that ABSL3 multicenter alliance and nonclinical evaluation protocol standardization can promote reliable efficacy testing against COVID-19, thus expediting medical product development.

Adipose Tissue-Derived Mesenchymal Stem Cells Extend the Lifespan and Enhance Liver Function in Hepatocyte Organoids.

In this study, we generated hepatocyte organoids (HOs) using frozen-thawed primary hepatocytes (PHs) within a three-dimensional (3D) Matrigel dome culture in a porcine model. Previously studied hepatocyte organoid analogs, spheroids, or hepatocyte aggregates created using PHs in 3D culture systems have limitations in their in vitro lifespans. By co-culturing adipose tissue-derived mesenchymal stem cells (A-MSCs) with HOs within a 3D Matrigel dome culture, we achieved a 3.5-fold increase in the in vitro lifespan and enhanced liver function compared to a conventional two-dimensional (2D) monolayer culture, i.e., more than twice that of the HO group cultured alone, reaching up to 126 d. Although PHs were used to generate HOs, we identified markers associated with cholangiocyte organoids such as cytokeratin 19 and epithelial cellular adhesion molecule (EPCAM). Co-culturing A-MSCs with HOs increased the secretion of albumin and urea and glucose consumption compared to HOs cultured alone. After more than 100 d, we observed the upregulation of tumor protein P53 (TP53)-P21 and downregulation of EPCAM, albumin (ALB), and cytochrome P450 family 3 subfamily A member 29 (CYP3A29). Therefore, HOs with function and longevity improved through co-culturing with A-MSCs can be used to create large-scale human hepatotoxicity testing models and precise livestock nutrition assessment tools.

No Interference of H9 Extract on Trastuzumab Pharmacokinetics in Their Combinations.

Trastuzumab is used to treat breast cancer patients overexpressing human epidermal growth factor receptor 2, but resistance and toxicity limit its uses, leading to attention to trastuzumab combinations. Recently, the synergistic effect of trastuzumab and H9 extract (H9) combination against breast cancer has been reported. Because drug exposure determines its efficacy and toxicity, the question of whether H9 changes trastuzumab exposure in the body has been raised. Therefore, this study aimed to characterize trastuzumab pharmacokinetics and elucidate the effect of H9 on trastuzumab pharmacokinetics at a combination dose that shows synergism in mice. As a result, trastuzumab showed linear pharmacokinetics after its intravenous administration from 1 to 10 mg/kg. In the combination of trastuzumab and H9, single and 2-week treatments of oral H9 (500 mg/kg) did not influence trastuzumab pharmacokinetics. In the multiple-combination treatments of trastuzumab and H9 showing their synergistic effect (3 weeks of trastuzumab with 2 weeks of H9), the pharmacokinetic profile of trastuzumab was comparable to that of 3 weeks of trastuzumab alone. In tissue distribution, the tissue to plasma ratios of trastuzumab below 1.0 indicated its limited distributions within the tissues, and these patterns were unaffected by H9. These results suggest that the systemic and local exposures of trastuzumab are unchanged by single and multiple-combination treatments of H9.

Obstetric and neonatal outcomes of gestational diabetes mellitus in twin pregnancies according to changes in its diagnostic criteria from National Diabetes Data Group criteria to Carpenter and Coustan criteria: a retrospective cohort study.

BACKGROUND: To compare obstetric and neonatal outcomes in twin pregnancies with or without gestational diabetes mellitus (GDM) before and after changes in GDM diagnostic criteria. METHODS: This was a retrospective cohort study of 1,764 twin pregnancies including 130 women with GDM (GDM group) and 1,634 women without GDM (non-GDM group). Patients with pregestational diabetes, unknown GDM status, and fetal death at < 24 gestational weeks were excluded. Obstetric and neonatal outcomes were compared between the two groups by two periods: period 1 (1995-2005) and period 2 (2005-2018) when National Diabetes Data Group criteria and Carpenter and Coustan criteria were used for diagnosis of GDM, respectively. RESULTS: The incidence of GDM in twin pregnancies increased from 4.0% in period 1 to 9.3% in period 2. Composite obstetric complications rate was significantly higher in the GDM group than that in the non-GDM group during period 1 (72.0% vs. 45.5%, P = 0.009). However, it became comparable during period 2 (60.0% vs. 57.4%, P = 0.601). Interaction between GDM and period indicated a significant differential effect of GDM by period on the rate of composite obstetric complications. The rate of composite neonatal complications was similar between the two groups during both periods. The interaction between GDM and period was not significant. CONCLUSION: After changes of GDM diagnostic criteria, the incidence of GDM increased more than twice, and the rate of composite obstetric complications decreased, but the rate of composite neonatal complications did not change significantly.

Predictive value of quad serum markers for adverse pregnancy outcome in antiphospholipid antibody syndrome.

PURPOSE: We investigated the validity of quad serum markers for the prediction of adverse pregnancy outcome (APO) in women with antiphospholipid antibody syndrome (APS). METHODS: We included 75 women with APS delivered at our institution. APO was defined as stillbirth, small for gestational age (SGA), severe preeclampsia, or preterm delivery. First, we compared clinical characteristics between patients with or without composite APO. Second, we compared the rate of APO according to abnormal level of quad serum markers. Lastly, receiver operating characteristic (ROC) curve analysis was performed. RESULTS: APS mothers with APO showed higher median α-fetoprotein (AFP) and inhibin A compared with those without APO. They were also associated with higher rates of positive risk of Down syndrome and neural tube defect. Elevated AFP, human chorionic gonadotropin (hCG), and inhibin A level was associated with higher rates of stillbirth, SGA, preterm delivery, and composite APO. ROC curve for prediction of stillbirth revealed an area under the curve of 0.835 for AFP, 0.781 for hCG, and 0.932 for inhibin A. For composite APO, the area under the ROC curve was 0.692 for AFP and 0.810 for inhibin A. CONCLUSION: Elevated AFP, hCG, and inhibin A in women with APS demonstrated a high predictive value for APO, especially stillbirth.

Validation of a Strict Obesity Definition Proposed for Asians to Predict Adverse Pregnancy Outcomes in Korean Pregnant Women.

BACKGROUND: People are generally considered overweight and obese if their body mass index (BMI) is above 25 kg/m² and 30.0 kg/m², respectively. The World Health Organization proposed stricter criteria for Asians (≥ 23 kg/m²: overweight, ≥ 25 kg/m²: obese). We aimed to verify whether this criteria could predict adverse pregnancy outcomes in Korean women. METHODS: We included 7,547 Korean women from 12 institutions enrolled between June 2016 and October 2018. Women with no pre-pregnancy BMI data, not Korean, or lost to follow-up were excluded, leaving 6,331. The subjects were categorized into underweight, normal, overweight, class I obesity, and class II/III obesity based on a pre-pregnancy BMI of < 18.5, 18.5-22.9, 23.0-24.9, 25.0-29.9, and ≥ 30.0 kg/m², respectively. RESULTS: Overall, 13.4%, 63.0%, 11.8%, 9.1%, and 2.6% of women were underweight, normal, and overweight and had class I obesity and class II/III obesity, respectively. In the multivariable analysis adjusted for maternal age, a higher BMI significantly increased the risk of preeclampsia, gestational diabetes, preterm delivery caused by maternal-fetal indications, cesarean section, large for gestational age, and neonatal intensive care unit admission. CONCLUSION: Adverse pregnancy outcomes started to increase in those with a pre-pregnancy BMI ≥ 23.0 kg/m² after adjusting for maternal age. The modified obesity criteria could help predict adverse pregnancy outcomes in Koreans.

Degree of intrapartum fever and associated factors: Three group analysis of no fever, borderline and overt fever.

AIM: Previous studies analyzing intrapartum fever by dichotomization of fever just above 38.0°C or not may lead to overlook clinical significance of borderline fever. We aimed to investigate the maternal baseline and intrapartum characteristics, neonatal outcomes, and inflammatory placental pathology in relation to the degree of intrapartum fever by three group analysis. METHODS: We performed a retrospective analysis of consecutive singleton deliveries between 370/7 to 410/7 weeks divided into three groups based on the peak body temperature during labor: No fever (< 37.5°C), borderline fever (≥ 37.5°C and < 38.0°C), and overt fever (≥ 38.0°C). Maternal and intrapartum characteristics, neonatal outcomes, and inflammatory placental pathology were compared by trend analysis, intergroup difference analysis, and multivariable analysis. RESULTS: The degree of intrapartum fever was significantly associated with younger maternal age, nulliparity, longer duration of rupture of membrane, and epidural analgesia (p < 0.001). And the incidence of neonatal proven sepsis and mortality were not significantly different among the groups. The degree of intrapartum fever was associated with the stage of acute chorioamnionitis and funisitis (p < 0.001). Multivariate analysis revealed that the association with epidural analgesia was stronger in borderline fever than overt fever (adjusted odds ratio [95% confidence interval], borderline fever = 18.487 [11.447-29.857]; overt fever = 11.068 [4.874-25.133]) after controlling for maternal age, parity, induction or augmentation, duration of ROM, birth weight, and meconium staining. CONCLUSION: Our data support that both epidural analgesia and inflammation of the placenta may contribute to the development of intrapartum fever at term.

Characterization of the copper-sensing transcriptional regulator CopR from the hyperthermophilic archeaon Thermococcus onnurineus NA1.

A putative copper ion-sensing transcriptional regulator CopR (TON_0836) from Thermococcus onnurineus NA1 was characterized. The CopR protein consists of a winged helix-turn-helix DNA-binding domain in the amino-terminal region and a TRASH domain that is assumed to be involved in metal ion-sensing in the carboxyl-terminal region. The CopR protein was most strongly bound to a region between its own gene promoter and a counter directional promoter region for copper efflux system CopA. When the divalent metals such as nickel, cobalt, copper, and iron were present, the CopR protein was dissociated from the target promoters on electrophoretic mobility shift assay (EMSA). The highest sensible ion is copper which affected protein releasing under 10 µM concentrations. CopR recognizes a significant upstream region of TATA box on CopR own promoter and acts as a transcriptional repressor in an in vitro transcription assay. Through site-directed mutagenesis of the DNA-binding domain, R34M mutant protein completely lost the DNA-binding activity on target promoter. When the conserved cysteine residues in C144XXC147 motif 1 of the TRASH domain were mutated into glycine, the double cysteine residue mutant protein alone lost the copper-binding activity. Therefore, CopR is a copper-sensing transcriptional regulator and acts as a repressor for autoregulation and for a putative copper efflux system CopA of T. onnurineus NA1.

Hypoxia-inducible transgelin 2 selects epithelial-to-mesenchymal transition and γ-radiation-resistant subtypes by focal adhesion kinase-associated insulin-like growth factor 1 receptor activation in non-small-cell lung cancer cells.

Microenvironment, such as hypoxia common to cancer, plays a critical role in the epithelial-to-mesenchymal transition (EMT) program, which is a major route of cancer metastasis and confers γ-radiation resistance to cells. Herein, we showed that transgelin 2 (TAGLN2), an actin-binding protein, is significantly induced in hypoxic lung cancer cells and that Snail1 is simultaneously increased, which induces EMT by downregulating E-cadherin expression. Forced TAGLN2 expression induced severe cell death; however, a small population of cells surviving after forced TAGLN2 overexpression showed γ-radiation resistance, which might promote tumor relapse and recurrence. These surviving cells showed high metastatic activity with an increase of EMT markers including Snail1. In these cells, TAGLN2 activated the insulin-like growth factor 1 receptor ß (IGF1Rß)/PI3K/AKT pathway by recruitment of focal adhesion kinase to the IGF1R signaling complex. Activation of the IGF1Rß/PI3K/AKT pathway also induced inactivation of glycogen synthase kinase 3ß (GSK3ß), which is involved in Snail1 stabilization. Therefore, both the IGF1Rß inhibitor (AG1024) and the PI3K inhibitor (LY294002) or AKT inactivation with MK2206 lower the cellular level of Snail1. Involvement of GSK3ß was also confirmed by treatment with lithium chloride, the inducer of GSK3ß phosphorylation, or MG132, the 26S proteasomal inhibitor, which also stabilized Snail1. In conclusion, the present study provides important evidence that hypoxia-inducible TAGLN2 is involved in the selection of cancer cells with enhanced EMT properties to overcome the detrimental environment of cancer cells.

ROS-Responsive Biomaterial Design for Medical Applications.

Stimuli-responsive biomaterials undergo significant alterations in material structure and property in response to changes of local environmental factors (e.g. pH, temperature, enzyme activation, and water absorption). In particular, reactive oxygen species (ROS) is considered as a major stimulus because over-production of ROS involves most types of major pathogenesis. The application of ROS-responsive biomaterials requires suitable material designs to program user-defined changes of their structure and property in response to a sudden change in the local ROS level. This chapter summarizes the progress in designing and applying major types of ROS-responsive biomaterials within the past 10 years.

APBB1 reinforces cancer stem cell and epithelial-to-mesenchymal transition by regulating the IGF1R signaling pathway in non-small-cell lung cancer cells.

Amyloid ß precursor protein binding family B member 1(APBB1) was first identified as a binding partner of amyloid precursor protein during brain development, but its function in the context of cancer remain unclear. Here we show for the first time that APBB1 is partly associated with intensifying cancer stem cell(CSC) and epithelial-to-mesenchymal transition (EMT) and enhancing radiation-resistant properties of lung cancer cells. We found that APBB1 was highly expressed in ALDH1high CSC-like cells sorted from A549 lung cancer cells. In APBB1-deficient H460 cells with forced overexpression of APBB1, the protein directly interacted with IGF1Rß, enhanced phosphorylation of IGF1Rß/PI3K/AKT pathway(activation) and subsequently induced the phosphorylation of GSK3ß(inactivation). This phosphorylation stabilized Snail1, a negative regulator of E-cadherin expression, and regulated ß-catenin-mediated ALDH1 expression, which are representative markers for EMT and CSCs, respectively. In contrast, suppression of APBB1 expression with siRNA yielded the opposite effects in APBB1-rich A549 cells. We concluded that APBB1 partly regulates the expression of ALDH1. We also found that APBB1 regulates activation of nuclear factor-κB, which is involved in reducing various stresses including oxidative stress, which suggests that APBB1 is associated with γ-radiation sensitivity. Our findings imply that APBB1 plays an important role in the maintenance of EMT-associated CSC-like properties and γ-radiation resistance via activation of IGF1Rß/AKT/GSK3ß pathway in lung cancer cells, highlighting APBB1 as a potential target for therapeutic cancer treatment.

STA1, an Arabidopsis pre-mRNA processing factor 6 homolog, is a new player involved in miRNA biogenesis.

MicroRNAs (miRNAs) are small regulatory RNAs that have important regulatory roles in numerous developmental and metabolic processes in most eukaryotes. In Arabidopsis, DICER-LIKE1 (DCL1), HYPONASTIC LEAVES 1, SERRATE, HUA ENHANCER1 and HASTY are involved in processing of primary miRNAs (pri-miRNAs) to yield precursor miRNAs (pre-miRNAs) and eventually miRNAs. In addition to these components, mRNA cap-binding proteins, CBP80/ABA HYPERSENSITIVE1 and CBP20, also participate in miRNA biogenesis. Here, we show that STABILIZED1 (STA1), an Arabidopsis pre-mRNA processing factor 6 homolog, is also involved in the biogenesis of miRNAs. Similar to other miRNA biogenesis-defective mutants, sta1-1 accumulated significantly lower levels of mature miRNAs and concurrently higher levels of pri-miRNAs than wild type. The dramatic reductions of mature miRNAs were associated with the accumulation of their target gene transcripts and developmental defects. Furthermore, sta1-1 impaired splicing of intron containing pri-miRNAs and decreased transcript levels of DCL1. These results suggest that STA1 is involved in miRNA biogenesis directly by functioning in pri-miRNA splicing and indirectly by modulating the DCL1 transcript level.

Differences in videofluoroscopic swallowing study (VFSS) findings according to the vascular territory involved in stroke.

Dysphagia affects up to half of stroke patients and increases the risk of pneumonia and fatal outcomes. In order to assess swallowing difficulty, videofluoroscopic swallowing study (VFSS) has traditionally been the gold standard. The purpose of this study was to compare the patterns of post-stroke swallowing difficulties according to the vascular territories involved in the stroke. One hundred and three patients who were diagnosed with first ischemic stroke by brain magnetic resonance imaging and had swallowing difficulty were included in this study. Location of the stroke was classified into three groups: territorial anterior infarcts (TAI) (n = 62), territorial posterior infarcts (TPI) (n = 19) and white matter disease (WMD) (n = 22). Oral cavity residue existed significantly in the TAI group more than in any other groups (P = 0.017). The WMD group showed more residue in the valleculae (P = 0.002) and the TPI group showed more residue in the pyriform sinuses (P = 0.001). The oral transit time, pharyngeal delay time and pharyngeal transit time did not show significant differences among the groups with swallowing of both thick and thin liquids. Penetration and aspiration were more frequent in the TPI group (P < 0.05) with swallowing of both thick and thin liquids. The results suggest that TAI is more related to oral phase dysfunction and TPI is more related to pharyngeal dysfunction. In ischemic stroke, patterns of swallowing difficulty may differ according to the vascular territory involved and this should be considered in the management of post-stroke dysphagia.

Methyl Pyruvate Oxime as a Carbonyl Synthon: Synthesis of Ureas, Carbamates, Thiocarbamates, and Anilides.

A new strategy for the synthesis of unsymmetrical ureas, carbamates, thiocarbamates, and anilides was developed with methyl pyruvate oxime as the carbonyl synthon. The intrinsic reactivity of the reagent enabled consecutive disubstitution involving direct amidation and one-pot deoximative substitution with various nucleophiles. The utility of the method was demonstrated with the synthesis of bioactive molecules.

Exosomal LINC00853 promotes progression of gastric cancer via the MAP17/PDZK1/AKT signaling pathway.

Although rare, there is ongoing research into biomarkers that predict the onset and recurrence of gastric cancer, particularly focusing on substances found in exosomes. Long non-coding RNAs (lncRNAs) have garnered attention for their potential in diagnosing gastric cancer. This study investigates the role of lncRNAs in gastric cancer, focusing on their presence in exosomes as potential biomarkers for the disease's onset and recurrence. We utilized the ArrayStar Human LncRNA array 2.0 to analyze lncRNA expression in tissues from early-stage gastric cancer patients. Our analysis highlighted LINC00853, which was significantly upregulated in cancer tissues and implicated in promoting epithelial-mesenchymal transition via the MAP17/PDZK1/AKT pathway. Functional studies on AGS and MKN74 gastric cancer cell lines demonstrated that LINC00853 facilitates cell proliferation, invasion, and migration. Additionally, RNA immunoprecipitation and electrophoretic mobility shift assays confirmed LINC00853 interaction with MAP17. Importantly, LINC00853 was also detected in exosomes from both patient samples and cell lines, and its downregulation led to decreased tumorigenicity in AGS cells. These findings suggest that both cellular and exosomal LINC00853 contribute to gastric cancer pathogenesis and may serve as valuable biomarkers for the disease.

Immunogenicity and Cross-Protection Efficacy of a Genotype F-Derived Attenuated Virus Vaccine Candidate against Mumps Virus in Mice.

Mumps virus (MuV) causes an acute contagious human disease characterized by swelling of the parotid glands. Despite the near elimination of mumps in many countries, the disease has recurred, even in vaccinated populations, especially adolescents. Immunization effectivity of the genotype A vaccine strain Jeryl Lynn (JL) is declining as genotype A is no longer predominant; therefore, a new vaccine strain and booster vaccine are required. We generated a cell culture-adapted MuV genotype F called F30 and evaluated its immunogenicity and cross-protective activity against diverse genotypes. F30 genome nucleotide sequence determination revealed changes in the NP, L, SH, and HN genes, leading to five amino acid changes compared to a minimally passaged stock (F10). F30 showed delayed growth, smaller plaque size in Vero cells, and lower neurotoxicity in neonatal mice than F10. Furthermore, F30 was immunogenic to other genotypes, including the JL vaccine strain, with higher efficacy than that of JL for homologous and heterologous immunization. Further, F30 exhibited cross-protective immunity against MuV genotypes F and G in Ifnar-/- mice after a third immunization with F30 following two doses of JL. Our data suggest that the live-attenuated virus F30 could be an effective booster vaccine to control breakthrough infections and mumps epidemics.

Impact of resident participation on surgical outcomes in laparoscopically assisted vaginal hysterectomy.

OBJECTIVE: To compare surgical outcomes in patients with benign diseases who underwent laparoscopically assisted vaginal hysterectomy (LAVH) to determine the association between surgical outcomes and resident participation in the gynecologic field. METHODS: A single-center retrospective study was conducted of patients diagnosed with benign gynecologic diseases who underwent LAVH between January 2010 and December 2015. Clinicopathologic characteristics and surgical outcomes were compared between the resident involvement and non-involvement groups. The primary endpoint was the 30-day postoperative morbidity. Observers were propensity matched for 17 covariates for resident involvement or non-involvement. RESULTS: Of the 683 patients involved in the study, 165 underwent LAVH with resident involvement and 518 underwent surgery without resident involvement. After propensity score matching (157 observations), 30-day postoperative morbidity occurred in 6 (3.8%) and 4 (2.5%) patients in the resident involvement and non-involvement groups, respectively (P = 0.501). The length of hospital stay differed significantly between the two groups: 5 days in the resident involvement group and 4 days in the non-involvement group (P < 0.001). On multivariate analysis, Charlson Comorbidity Index >2 (odds ratio [OR] 8.01, 95% confidence interval [CI] 2.68-23.96; P < 0.001), operative time (OR 1.02, 95% CI 1.01-1.03; P < 0.001), and estimated blood loss (OR 1.00, 95% CI 1.00-1.00; P < 0.001) were significantly associated with 30-day morbidity, but resident involvement was not statistically significant. CONCLUSION: There was no significant difference in the 30-day morbidity rate when residents participated in LAVH. These findings suggest that resident participation in LAVH may be a viable approach to ensure both residency education and patient safety.

ER procollagen storage defect without coupled unfolded protein response drives precocious arthritis.

Collagenopathies are a group of clinically diverse disorders caused by defects in collagen folding and secretion. For example, mutations in the gene encoding collagen type-II, the primary collagen in cartilage, can lead to diverse chondrodysplasias. One example is the Gly1170Ser substitution in procollagen-II, which causes precocious osteoarthritis. Here, we biochemically and mechanistically characterize an induced pluripotent stem cell-based cartilage model of this disease, including both hetero- and homozygous genotypes. We show that Gly1170Ser procollagen-II is notably slow to fold and secrete. Instead, procollagen-II accumulates intracellularly, consistent with an endoplasmic reticulum (ER) storage disorder. Owing to unique features of the collagen triple helix, this accumulation is not recognized by the unfolded protein response. Gly1170Ser procollagen-II interacts to a greater extent than wild-type with specific proteostasis network components, consistent with its slow folding. These findings provide mechanistic elucidation into the etiology of this disease. Moreover, the cartilage model will enable rapid testing of therapeutic strategies to restore proteostasis in the collagenopathies.

Necking Reduction at Low Temperature in Aspect Ratio Etching of SiO2 at CF4/H2/Ar Plasma.

This study investigated the effect of temperature on the aspect-ratio etching of SiO2 in CF4/H2/Ar plasma using patterned samples of a 200 nm trench in a low-temperature reactive-ion etching system. Lower temperatures resulted in higher etch rates and aspect ratios for SiO2. However, the plasma property was constant with the chuck temperature, indicated by the line intensity ratio from optical emission spectroscopy monitoring of the plasma. The variables obtained from the characterization of the etched profile for the 200 nm trench after etching were analyzed as a function of temperature. A reduction in the necking ratio affected the etch rate and aspect ratio of SiO2. The etching mechanism of the aspect ratio etching of SiO2 was discussed based on the results of the surface composition at necking via energy-dispersive X-ray spectroscopy with temperature. The results suggested that the neutral species reaching the etch front of SiO2 had a low sticking coefficient. The bowing ratio decreased with lowering temperature, indicating the presence of directional ions during etching. Therefore, a lower temperature for the aspect ratio etching of SiO2 could achieve a faster etch rate and a higher aspect ratio of SiO2 via the reduction of necking than higher temperatures.

A longitudinal molecular and cellular lung atlas of lethal SARS-CoV-2 infection in K18-hACE2 transgenic mice.

BACKGROUND: The global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to approximately 500 million cases and 6 million deaths worldwide. Previous investigations into the pathophysiology of SARS-CoV-2 primarily focused on peripheral blood mononuclear cells from patients, lacking detailed mechanistic insights into the virus's impact on inflamed tissue. Existing animal models, such as hamster and ferret, do not faithfully replicate the severe SARS-CoV-2 infection seen in patients, underscoring the need for more relevant animal system-based research. METHODS: In this study, we employed single-cell RNA sequencing (scRNA-seq) with lung tissues from K18-hACE2 transgenic (TG) mice during SARS-CoV-2 infection. This approach allowed for a comprehensive examination of the molecular and cellular responses to the virus in lung tissue. FINDINGS: Upon SARS-CoV-2 infection, K18-hACE2 TG mice exhibited severe lung pathologies, including acute pneumonia, alveolar collapse, and immune cell infiltration. Through scRNA-seq, we identified 36 different types of cells dynamically orchestrating SARS-CoV-2-induced pathologies. Notably, SPP1+ macrophages in the myeloid compartment emerged as key drivers of severe lung inflammation and fibrosis in K18-hACE2 TG mice. Dynamic receptor-ligand interactions, involving various cell types such as immunological and bronchial cells, defined an enhanced TGFß signaling pathway linked to delayed tissue regeneration, severe lung injury, and fibrotic processes. INTERPRETATION: Our study provides a comprehensive understanding of SARS-CoV-2 pathogenesis in lung tissue, surpassing previous limitations in investigating inflamed tissues. The identified SPP1+ macrophages and the dysregulated TGFß signaling pathway offer potential targets for therapeutic intervention. Insights from this research may contribute to the development of innovative diagnostics and therapies for COVID-19. FUNDING: This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (2020M3A9I2109027, 2021R1A2C2004501).