Review of COVID-19 Therapeutics by Mechanism: From Discovery to Approval.

The global research and pharmaceutical community rapidly mobilized to develop treatments for coronavirus disease 2019 (COVID-19). Existing treatments have been repurposed and new drugs have emerged. Here we summarize mechanisms and clinical trials of COVID-19 therapeutics approved or in development. Two reviewers, working independently, reviewed published data for approved COVID-19 vaccines and drugs, as well as developmental pipelines, using databases from the following organizations: United States Food and Drug Administration (US-FDA), European Medicines Agency (EMA), Japanese Pharmaceutical and Medical Devices Agency (PMDA), and ClinicalTrials.gov. In all, 387 drugs were found for initial review. After removing unrelated trials and drugs, 66 drugs were selected, including 17 approved drugs and 49 drugs under development. These drugs were classified into six categories: 1) drugs targeting the viral life cycle 2) Anti-severe acute respiratory syndrome coronavirus 2 Monoclonal Antibodies, 3) immunomodulators, 4) anti-coagulants, 5) COVID-19-induced neuropathy drugs, and 6) other therapeutics. Among the 49 drugs under development are the following: 6 drugs targeting the viral life cycle, 12 immunosuppression drugs, 2 immunostimulants, 2 HIF-PHD targeting drugs, 3 GM-CSF targeting drugs, 5 anti-coagulants, 2 COVID-19-induced neuropathy drugs, and 17 others. This review provides insight into mechanisms of action, properties, and indications for COVID-19 medications.

Correction to: Licochalcone A induces apoptosis through endoplasmic reticulum stress via a phospholipase Cγ1-, Ca2+-, and reactive oxygen species-dependent pathway in HepG2 human hepatocellular carcinoma cells.

The original version of this article contained mistakes in figures. The western blot data for pro-caspase-3 and cleaved caspase-3 (Fig. 1d), ß-actin (Fig. 1d), PLCγ1 (Fig. 5d), and eIF2α (Fig. 7d) are incorrect. The corrected Figs. 1d, 5d, and 7d are shown below. The corrections do not influence either the validity of the published data or the conclusion described in the article.

Correction to: Apicidin induces endoplasmic reticulum stress- and mitochondrial dysfunction-associated apoptosis via phospholipase Cγ1- and Ca2+-dependent pathway in mouse Neuro-2a neuroblastoma cells.

The original version of this article contained a mistake in the figure. The Ca2 + confocal image for the 2-APB/Apicidin-120 min in Fig. 5d is incorrect. The correction does not influence either the validity of the published data or the conclusion described in the article. The corrected Fig. 5d is given below.

Integrative analysis of genes and miRNA alterations in human embryonic stem cells-derived neural cells after exposure to silver nanoparticles.

Given the rapid growth of engineered and customer products made of silver nanoparticles (Ag NPs), understanding their biological and toxicological effects on humans is critically important. The molecular developmental neurotoxic effects associated with exposure to Ag NPs were analyzed at the physiological and molecular levels, using an alternative cell model: human embryonic stem cell (hESC)-derived neural stem/progenitor cells (NPCs). In this study, the cytotoxic effects of Ag NPs (10-200µg/ml) were examined in these hESC-derived NPCs, which have a capacity for neurogenesis in vitro, at 6 and 24h. The results showed that Ag NPs evoked significant toxicity in hESC-derived NPCs at 24h in a dose-dependent manner. In addition, Ag NPs induced cell cycle arrest and apoptosis following a significant increase in oxidative stress in these cells. To further clarify the molecular mechanisms of the toxicological effects of Ag NPs at the transcriptional and post-transcriptional levels, the global expression profiles of genes and miRNAs were analyzed in hESC-derived NPCs after Ag NP exposure. The results showed that Ag NPs induced oxidative stress and dysfunctional neurogenesis at the molecular level in hESC-derived NPCs. Based on this hESC-derived neural cell model, these findings have increased our understanding of the molecular events underlying developmental neurotoxicity induced by Ag NPs in humans.

Licochalcone A induces apoptosis through endoplasmic reticulum stress via a phospholipase Cγ1-, Ca(2+)-, and reactive oxygen species-dependent pathway in HepG2 human hepatocellular carcinoma cells.

Licochalcone A (LicA), an estrogenic flavonoid, induces apoptosis in multiple types of cancer cells. In this study, the molecular mechanisms underlying the anti-cancer effects of LicA were investigated in HepG2 human hepatocellular carcinoma cells. LicA induced apoptotic cell death, activation of caspase-4, -9, and -3, and expression of endoplasmic reticulum (ER) stress-associated proteins, including C/EBP homologous protein (CHOP). Inhibition of ER stress by CHOP knockdown or treatment with the ER stress inhibitors, salubrinal and 4-phenylbutyric acid, reduced LicA-induced cell death. LicA also induced reactive oxygen species (ROS) accumulation and the anti-oxidant N-acetylcysteine reduced LicA-induced cell death and CHOP expression. In addition, LicA increased the levels of cytosolic Ca(2+), which was blocked by 2-aminoethoxydiphenyl borate (an antagonist of inositol 1,4,5-trisphosphate receptor) and BAPTA-AM (an intracellular Ca(2+) chelator). 2-Aminoethoxydiphenyl borate and BAPTA-AM inhibited LicA-induced cell death. Interestingly, LicA induced phosphorylation of phospholipase Cγ1 (PLCγ1) and inhibition of PLCγ1 reduced cell death and ER stress. Moreover, the multi-targeted receptor tyrosine kinase inhibitors, sorafenib and sunitinib, reduced LicA-induced cell death, ER stress, and cytosolic Ca(2+) and ROS accumulation. Finally, LicA induced phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR2) and c-Met receptor and inhibition of both receptors by co-transfection with VEGFR2 and c-Met siRNAs reversed LicA-induced cell death, Ca(2+) increase, and CHOP expression. Taken together, these findings suggest that induction of ER stress via a PLCγ1-, Ca(2+)-, and ROS-dependent pathway may be an important mechanism by which LicA induces apoptosis in HepG2 hepatocellular carcinoma cells.

Apicidin induces endoplasmic reticulum stress- and mitochondrial dysfunction-associated apoptosis via phospholipase Cγ1- and Ca(2+)-dependent pathway in mouse Neuro-2a neuroblastoma cells.

Apicidin, a fungal metabolite that functions as a histone deacetylase inhibitor, induces apoptosis in cancer cells. We investigated the molecular mechanisms of the anti-cancer effects of apicidin in mouse Neuro-2a neuroblastoma cells. Apicidin induced apoptotic cell death and activation of caspase-12, -9, and -3. Apicidin induced expression of endoplasmic reticulum (ER) stress-associated proteins, including CCAAT/enhancer binding protein homologous protein (CHOP), cleavage of activating transcription factor 6α, and phosphorylation of eukaryotic initiation factor 2α. Inhibition of ER stress by CHOP knockdown or using the ER stress inhibitors, salubrinal and 4-phenylbutyric acid, reduced apicidin-induced cell death. Apicidin induced reactive oxygen species accumulation and mitochondrial membrane potential loss. An antioxidant, N-acetyl cysteine, reduced apicidin-induced cell death, CHOP expression, and mitochondrial dysfunction. In addition, apicidin increased cytosolic Ca(2+), which was blocked by 2-aminoethoxydiphenyl borate, an antagonist of inositol 1,4,5-trisphosphate receptor, and BAPTA-AM, an intracellular Ca(2+) chelator. 2-Aminoethoxydiphenyl borate and BAPTA-AM inhibited apicidin-induced cell death and ER stress. Interestingly, apicidin induced phosphorylation of phospholipase Cγ1 (PLCγ1) and epidermal growth factor receptor (EGFR), and inhibition of PLCγ1 and EGFR reduced cell death and ER stress. Finally, apicidin-induced histone H3 hyperacetylation and reduction of histone deacetylase 2 mRNA expression were not affected by either a PLCγ1 inhibitor, U73122, or the antioxidant, N-acetyl cysteine. Taken together, the results suggest that apicidin induces apoptosis by ER stress and mitochondrial dysfunction via PLCγ1 activation, Ca(2+) release, and reactive oxygen species accumulation in Neuro-2a neuroblastoma cells.

Effect of two different doses of intravitreal bevacizumab with temporal retina-sparing laser photocoagulation for retinopathy of prematurity.

This study aims to compare the efficacy and safety between two different doses of intravitreal bevacizumab (IVB) injection with temporal retina-sparing laser (TRSL) photocoagulation for retinopathy of prematurity (ROP). We retrospectively evaluated 22 eyes of ROP infants who underwent IVB combined with partial TRSL for stage 3+ zone I or posterior zone II ROP. Laser photocoagulation was applied on the avascular retina, sparing two-disc-diameter width temporal avascular area anterior to ridge. A half dose (0.625 mg) or minimal dose (0.25 mg) of IVB was conducted. Four eyes in minimal dose group were retreated with IVB and laser photocoagulation on the spared retina. Of those 4 retreated eyes, three developed preretinal hemorrhage around the ridge after the first treatment, resulting in fibrotic macular dragging. A half dose of IVB may be more effective than a minimal dose with partial TRSL for ROP. Preretinal hemorrhage may be a harbinger of poor prognosis.

Corrugated Textile based Triboelectric Generator for Wearable Energy Harvesting.

Triboelectric energy harvesting has been applied to various fields, from large-scale power generation to small electronics. Triboelectric energy is generated when certain materials come into frictional contact, e.g., static electricity from rubbing a shoe on a carpet. In particular, textile-based triboelectric energy-harvesting technologies are one of the most promising approaches because they are not only flexible, light, and comfortable but also wearable. Most previous textile-based triboelectric generators (TEGs) generate energy by vertically pressing and rubbing something. However, we propose a corrugated textile-based triboelectric generator (CT-TEG) that can generate energy by stretching. Moreover, the CT-TEG is sewn into a corrugated structure that contains an effective air gap without additional spacers. The resulting CT-TEG can generate considerable energy from various deformations, not only by pressing and rubbing but also by stretching. The maximum output performances of the CT-TEG can reach up to 28.13 V and 2.71 µA with stretching and releasing motions. Additionally, we demonstrate the generation of sufficient energy from various activities of a human body to power about 54 LEDs. These results demonstrate the potential application of CT-TEGs for self-powered systems.

Stretchable, weavable coiled carbon nanotube/MnO2/polymer fiber solid-state supercapacitors.

Fiber and yarn supercapacitors that are elastomerically deformable without performance loss are sought for such applications as power sources for wearable electronics, micro-devices, and implantable medical devices. Previously reported yarn and fiber supercapacitors are expensive to fabricate, difficult to upscale, or non-stretchable, which limits possible use. The elastomeric electrodes of the present solid-state supercapacitors are made by using giant inserted twist to coil a nylon sewing thread that is helically wrapped with a carbon nanotube sheet, and then electrochemically depositing pseudocapacitive MnO2 nanofibers. These solid-state supercapacitors decrease capacitance by less than 15% when reversibly stretched by 150% in the fiber direction, and largely retain capacitance while being cyclically stretched during charge and discharge. The maximum linear and areal capacitances (based on active materials) and areal energy storage and power densities (based on overall supercapacitor dimensions) are high (5.4 mF/cm, 40.9 mF/cm(2), 2.6 µWh/cm(2) and 66.9 µW/cm(2), respectively), despite the engineered superelasticity of the fiber supercapacitor. Retention of supercapacitor performance during large strain (50%) elastic deformation is demonstrated for supercapacitors incorporated into the wristband of a glove.

Flexible supercapacitor made of carbon nanotube yarn with internal pores.

Electrochemical deposition of MnO2 onto carbon nanotube (CNT) yarn gives a high-performance, flexible yarn supercapacitor. The hybrid yarn's blended structure, resulting from trapping of MnO2 in its internal pores, effectively enlarges electrochemical area and reduces charge diffusion length. Accordingly, the yarn supercapacitor exhibits high values of capacitance, energy density, and average power density. Applications in wearable electronics can be envisaged.

AMP-activated protein kinase mediates T cell activation-induced expression of FasL and COX-2 via protein kinase C theta-dependent pathway in human Jurkat T leukemia cells.

AMP-activated protein kinase (AMPK), an important regulator of energy homeostasis, is known to be activated during T cell activation. T cell activation by T cell receptor (TCR) engagement or its pharmacological mimics, PMA plus ionomycin (PMA/Io), induces immunomodulatory FasL and cyclooxygenase-2 (COX-2) expression. In this study, we examined the role and mechanisms of AMPK in PMA/Io-induced expression of FasL and COX-2 in Jurkat T human leukemic cells. Inhibition of AMPK by a pharmacological agent, compound C, or AMPKα1 siRNA suppressed expression of FasL and COX-2 mRNAs and proteins in PMA/Io-activated Jurkat cells. It also reduced secretion of FasL protein and prostaglandin E2, a main product of COX-2, in Jurkat cells and peripheral blood lymphocytes activated with PMA/Io or monoclonal anti-CD3 plus anti-CD28. Consistently, inhibition of AMPK blocked promoter activities of FasL and COX-2 in activated Jurkat cells. As protein kinase C theta (PKCθ) is a central molecule for TCR signaling, we examined any possible cross-talk between AMPK and PKCθ in activated T cells. Of particular importance, we found that inhibition of AMPK blocked phosphorylation and activation of PKCθ, suggesting that AMPK is an upstream kinase of PKCθ. Moreover, we showed that AMPK was directly associated with PKCθ and phosphorylated Thr538 of PKCθ in PMA/Io-stimulated Jurkat cells. We also showed that inhibition of PKCθ by rottlerin or dominant negative PKCθ reduced AMPK-mediated transcriptional activation of NF-AT and AP-1 in activated Jurkat cells. Taken together, these results suggest that AMPK regulates expression of FasL and COX-2 via the PKCθ and NF-AT and AP-1 pathways in activated Jurkat cells.

Comparison of various treatment modalities for acute tinnitus.

OBJECTIVES/HYPOTHESIS: Because in most cases the development of tinnitus is triggered by cochlear damage, there exists the opportunity to eliminate tinnitus while the cochlear lesion is still reversible. Therefore, we evaluated the therapeutic effects of various treatment modalities on acute subjective idiopathic tinnitus (SIT) and investigated prognostic factors affecting the treatment outcome. STUDY DESIGN: Prospective, controlled, double-blind trial. METHODS: A total 107 patients who underwent treatment for unilateral SIT that had developed within the previous 3 months completed the study. The patients were randomly assigned into three groups according to the treatment modality: group I (n = 32), alprazolam orally for 3 months; group II (n = 35), as for group I plus four intratympanic dexamethasone (ITD) injections; and group III (n = 40), as for group II plus four intravenous injections of lipo-prostaglandin E(1) . RESULTS: The improvement rate of group II (75.8%) was significantly higher than that of group I (40.3%; P < .05), and there was no significant difference in the improvement rate of group III (50.0%) compared with groups I and II (P > .05). The cure rates of group II (25.8%) and group III (20.0%) were significantly higher than that of group I (9.8%; P < .05). There was a significant correlation between the cure rate and duration of symptoms. CONCLUSIONS: The results of the present study indicate that ITD injection plus alprazolam medication is the best treatment choice for acute SIT within 3 months of development.

Is cognitive function in adults with hearing impairment improved by the use of hearing AIDS?

OBJECTIVES: In the present study, we investigated whether speech-related cognitive function and speech recognition ability under background noise in adults with hearing impairment are improved with the use of hearing aids. METHODS: Participants were recruited from the ENT Department of Eulji Hospital from September 2008 to July 2009. The study group comprised 18 participants (mean age, 69.5±8.3 years) with sensorineural hearing loss who were fitted with hearing aids, and the control group comprised 11 participants of equivalent age (mean age, 63.1±11.8 years) who were not fitted with hearing aids. All participants were assessed using the computerized Korean visual verbal learning test (VVLT) and words-in-noise (WIN) test prior to fitting of hearing aids for the study group and initially for the control group. Both groups were reassessed in both tests after 6 months. For each group, differences in the results between the two assessments were compared using the Friedman test. RESULTS: There was no difference in mean age between the study group and control group. In the study group, total VVLT score (reflecting short-term memory) was significantly improved from before hearing aid use to 6 months after hearing aid use (P<0.05), and VVLT recognition score (reflecting learning ability) was also significantly improved from before hearing aid use to 6 months after hearing aid use (P<0.05), but there was no change in the control group. For VVLT latency score (reflecting efficiency of memory) and speech discrimination score in the WIN test, no statistically significant difference was found between the initial and 6-month assessments in the study group or in the control group (P>0.05). CONCLUSION: The speech-related cognitive function of individuals with hearing impairment improved after using hearing aids. This finding indicates that hearing aids may induce acclimatization of the central auditory system.

Luteolin induces apoptosis through endoplasmic reticulum stress and mitochondrial dysfunction in Neuro-2a mouse neuroblastoma cells.

Luteolin, a dietary flavonoid, induces apoptosis in various types of cancer cells. However, its role in neuroblastoma and the underlying mechanisms remain to be elucidated. In the present study, we investigated the molecular mechanisms of the anti-cancer effect of luteolin in Neuro-2a mouse neuroblastoma cells. Luteolin induced apoptotic cell death and activation of caspase-12, -9, and -3, and knockdown of caspase-12 by siRNA transfection reduced luteolin-induced cell death. Luteolin also induced expression of endoplasmic reticulum (ER) stress-associated proteins, including C/EBP homologous protein (CHOP) and glucose-regulated proteins (GRP) 94 and 78, cleavage of ATF6α, and phosphorylation of eIF2α. CHOP knockdown or ER stress inhibitor, 4-phenylbutyric acid, reduced luteolin-induced cell death. These results suggest involvement of ER stress in luteolin-induced neuroblastoma cell death. We then showed that luteolin induced accumulation of reactive oxygen species and that the anti-oxidant N-acetylcysteine reduced luteolin-induced cell death and expression of CHOP and GRP78. We also demonstrated rapid reduction of mitochondrial membrane potential by luteolin, and N-acetylcysteine, as well as 4-phenylbutyric acid or CHOP siRNA transfection ameliorated luteolin-induced late loss, but not early loss of mitochondrial membrane potential. Finally, we showed that luteolin induced activation of mitogen-activated protein kinases such as JNK, p38, and ERK, and inhibitors of mitogen-activated protein kinases reduced luteolin-induced cell death and CHOP expression, as well as mitochondrial Bax translocation and cytochrome c release. Collectively, our results suggest that luteolin induces apoptosis through ER stress and mitochondrial dysfunction in Neuro-2a mouse neuroblastoma cells.

Baicalein protects HT22 murine hippocampal neuronal cells against endoplasmic reticulum stress-induced apoptosis through inhibition of reactive oxygen species production and CHOP induction.

Baicalein is one of the major flavonoids in Scutellaria baicalensis Georgi and possesses various effects, including cytoprotection and anti-inflammation. Because endoplasmic reticulum (ER) stress has been implicated in neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and cerebral ischemia, we investigated the effects of baicalein on apoptotic death of HT22 mouse hippocampal neuronal cells induced by thapsigargin (TG) and brefeldin A (BFA), two representative ER stress inducers. Apoptosis, reactive oxygen species (ROS) production, and mitochondrial membrane potential (MMP) were measured by flow cytometry. Expression level and phosphorylation status of ER stress-associated proteins and activation and cleavage of apoptosis-associated proteins were analyzed by Western blot. Baicalein reduced TG- and BFA-induced apoptosis of HT22 cells and activation and cleavage of apoptosis-associated proteins, such as caspase-12 and -3 and poly(ADP-ribose) polymerase. Baicalein also reduced the TG- and BFA-induced expression of ER stress-associated proteins, including C/EBP homologous protein (CHOP) and glucose-regulated protein 78, the cleavage of X-box binding protein-1 and activating transcription factor 6α, and the phosphorylation of eukaryotic initiation factor-2α and mitogen-activated protein kinases, such as p38, JNK, and ERK. Knock-down of CHOP expression by siRNA transfection and specific inhibitors of p38 (SB203580), JNK (SP600125), and ERK (PD98059) as well as anti-oxidant (N-acetylcysteine) reduced TG- or BFA-induced cell death. Baicalein also reduced TG- and BFA-induced ROS accumulation and MMP reduction. Taken together, these results suggest that baicalein could protect HT22 neuronal cells against ER stress-induced apoptosis by reducing CHOP induction as well as ROS accumulation and mitochondrial damage.

The Value of Measuring Eustachian Tube Aeration on Temporal Bone CT in Patients with Chronic Otitis Media.

OBJECTIVES: To evaluate that the cross-sectional area of the air space in the Eustachian tube (ET) on computed tomography (CT) images could be useful for predicting the postoperative aeration of the middle ear. METHODS: The patient group consisted of 80 patients (80 ears) with chronic otitis media and who underwent middle ear surgery from 2006-2007 and who were followed up for more than 1 yr. The control group consisted of 100 ears of 50 individuals with normal tympanic membranes and who underwent CT for other causes (such as tinnitus or hearing loss). The largest cross-sectional areas of the aerated ET were measured on the coronal images of the temporal bone CT by a single otologist using the computer-based "Region of Interest" picture archiving and communications system. The patient group was divided into two subgroups, 1) those with good postoperative aeration and 2) those with poor postoperative aeration. The largest cross-sectional areas of the aerated ETs were compared between the patients and the controls, and between the patients with good aeration and the patients with poor aeration. RESULTS: The mean cross-sectional areas significantly differed between the patient group and the control group, and between the good and poor aeration subgroups (P<0.05 each). The mean area of the poor aeration subgroup was smaller than that of the control group (P<0.05), but the mean area of the good aeration subgroup did not significantly differ from that of the controls. CONCLUSION: The cross-sectional area of the aerated ET, as measured on the preoperative coronal images of temporal bone CT scans, may be useful for predicting the postoperative condition of the tympanic cavity.