Virological characteristics of a SARS-CoV-2-related bat coronavirus, BANAL-20-236.

BACKGROUND: Although several SARS-CoV-2-related coronaviruses (SC2r-CoVs) were discovered in bats and pangolins, the differences in virological characteristics between SARS-CoV-2 and SC2r-CoVs remain poorly understood. Recently, BANAL-20-236 (B236) was isolated from a rectal swab of Malayan horseshoe bat and was found to lack a furin cleavage site (FCS) in the spike (S) protein. The comparison of its virological characteristics with FCS-deleted SARS-CoV-2 (SC2ΔFCS) has not been conducted yet. METHODS: We prepared human induced pluripotent stem cell (iPSC)-derived airway and lung epithelial cells and colon organoids as human organ-relevant models. B236, SARS-CoV-2, and artificially generated SC2ΔFCS were used for viral experiments. To investigate the pathogenicity of B236 in vivo, we conducted intranasal infection experiments in hamsters. FINDINGS: In human iPSC-derived airway epithelial cells, the growth of B236 was significantly lower than that of the SC2ΔFCS. A fusion assay showed that the B236 and SC2ΔFCS S proteins were less fusogenic than the SARS-CoV-2 S protein. The infection experiment in hamsters showed that B236 was less pathogenic than SARS-CoV-2 and even SC2ΔFCS. Interestingly, in human colon organoids, the growth of B236 was significantly greater than that of SARS-CoV-2. INTERPRETATION: Compared to SARS-CoV-2, we demonstrated that B236 exhibited a tropism toward intestinal cells rather than respiratory cells. Our results are consistent with a previous report showing that B236 is enterotropic in macaques. Altogether, our report strengthens the assumption that SC2r-CoVs in horseshoe bats replicate primarily in the intestinal tissues rather than respiratory tissues. FUNDING: This study was supported in part by AMED ASPIRE (JP23jf0126002, to Keita Matsuno, Kazuo Takayama, and Kei Sato); AMED SCARDA Japan Initiative for World-leading Vaccine Research and Development Centers "UTOPIA" (JP223fa627001, to Kei Sato), AMED SCARDA Program on R&D of new generation vaccine including new modality application (JP223fa727002, to Kei Sato); AMED SCARDA Hokkaido University Institute for Vaccine Research and Development (HU-IVReD) (JP223fa627005h0001, to Takasuke Fukuhara, and Keita Matsuno); AMED Research Program on Emerging and Re-emerging Infectious Diseases (JP21fk0108574, to Hesham Nasser; JP21fk0108493, to Takasuke Fukuhara; JP22fk0108617 to Takasuke Fukuhara; JP22fk0108146, to Kei Sato; JP21fk0108494 to G2P-Japan Consortium, Keita Matsuno, Shinya Tanaka, Terumasa Ikeda, Takasuke Fukuhara, and Kei Sato; JP21fk0108425, to Kazuo Takayama and Kei Sato; JP21fk0108432, to Kazuo Takayama, Takasuke Fukuhara and Kei Sato; JP22fk0108534, Terumasa Ikeda, and Kei Sato; JP22fk0108511, to Yuki Yamamoto, Terumasa Ikeda, Keita Matsuno, Shinya Tanaka, Kazuo Takayama, Takasuke Fukuhara, and Kei Sato; JP22fk0108506, to Kazuo Takayama and Kei Sato); AMED Research Program on HIV/AIDS (JP22fk0410055, to Terumasa Ikeda; and JP22fk0410039, to Kei Sato); AMED Japan Program for Infectious Diseases Research and Infrastructure (JP22wm0125008 to Keita Matsuno); AMED CREST (JP21gm1610005, to Kazuo Takayama; JP22gm1610008, to Takasuke Fukuhara; JST PRESTO (JPMJPR22R1, to Jumpei Ito); JST CREST (JPMJCR20H4, to Kei Sato); JSPS KAKENHI Fund for the Promotion of Joint International Research (International Leading Research) (JP23K20041, to G2P-Japan Consortium, Keita Matsuno, Takasuke Fukuhara and Kei Sato); JST SPRING (JPMJSP2108 to Shigeru Fujita); JSPS KAKENHI Grant-in-Aid for Scientific Research C (22K07103, to Terumasa Ikeda); JSPS KAKENHI Grant-in-Aid for Scientific Research B (21H02736, to Takasuke Fukuhara); JSPS KAKENHI Grant-in-Aid for Early-Career Scientists (22K16375, to Hesham Nasser; 20K15767, to Jumpei Ito); JSPS Core-to-Core Program (A. Advanced Research Networks) (JPJSCCA20190008, to Kei Sato); JSPS Research Fellow DC2 (22J11578, to Keiya Uriu); JSPS Research Fellow DC1 (23KJ0710, to Yusuke Kosugi); JSPS Leading Initiative for Excellent Young Researchers (LEADER) (to Terumasa Ikeda); World-leading Innovative and Smart Education (WISE) Program 1801 from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) (to Naganori Nao); Ministry of Health, Labour and Welfare (MHLW) under grant 23HA2010 (to Naganori Nao and Keita Matsuno); The Cooperative Research Program (Joint Usage/Research Center program) of Institute for Life and Medical Sciences, Kyoto University (to Kei Sato); International Joint Research Project of the Institute of Medical Science, the University of Tokyo (to Terumasa Ikeda and Takasuke Fukuhara); The Tokyo Biochemical Research Foundation (to Kei Sato); Takeda Science Foundation (to Terumasa Ikeda and Takasuke Fukuhara); Mochida Memorial Foundation for Medical and Pharmaceutical Research (to Terumasa Ikeda); The Naito Foundation (to Terumasa Ikeda); Hokuto Foundation for Bioscience (to Tomokazu Tamura); Hirose Foundation (to Tomokazu Tamura); and Mitsubishi Foundation (to Kei Sato).

Longitudinal analysis of genomic mutations in SARS-CoV-2 isolates from persistent COVID-19 patient.

A primary reason for the ongoing spread of coronavirus disease 2019 (COVID-19) is the continuous acquisition of mutations by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the mechanism of acquiring mutations is not fully understood. In this study, we isolated SARS-CoV-2 from an immunocompromized patient persistently infected with Omicron strain BF.5 for approximately 4 months to analyze its genome and evaluate drug resistance. Although the patient was administered the antiviral drug remdesivir (RDV), there were no acquired mutations in RDV binding site, and all isolates exhibited susceptibility to RDV. Notably, upon analyzing the S protein sequence of the day 119 isolate, we identified mutations acquired by mutant strains emerging from the BF.5 variant, suggesting that viral genome analysis in persistent COVID-19 patients may be useful in predicting viral evolution. These results suggest mutations in SARS-CoV-2 are acquired during long-term viral replication rather than in response to antiviral drugs.

Micro-patterned culture of iPSC-derived alveolar and airway cells distinguishes SARS-CoV-2 variants.

The emergence of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) variants necessitated a rapid evaluation system for their pathogenesis. Lung epithelial cells are their entry points; however, in addition to their limited source, the culture of human alveolar epithelial cells is especially complicated. Induced pluripotent stem cells (iPSCs) are an alternative source of human primary stem cells. Here, we report a model for distinguishing SARS-CoV-2 variants at high resolution, using separately induced iPSC-derived alveolar and airway cells in micro-patterned culture plates. The position-specific signals induced the apical-out alveolar type 2 and multiciliated airway cells at the periphery and center of the colonies, respectively. The infection studies in each lineage enabled profiling of the pathogenesis of SARS-CoV-2 variants: infection efficiency, tropism to alveolar and airway lineages, and their responses. These results indicate that this culture system is suitable for predicting the pathogenesis of emergent SARS-CoV-2 variants.

Virological characteristics of the SARS-CoV-2 Omicron XBB.1.5 variant.

Circulation of SARS-CoV-2 Omicron XBB has resulted in the emergence of XBB.1.5, a new Variant of Interest. Our phylogenetic analysis suggests that XBB.1.5 evolved from XBB.1 by acquiring the S486P spike (S) mutation, subsequent to the acquisition of a nonsense mutation in ORF8. Neutralization assays showed similar abilities of immune escape between XBB.1.5 and XBB.1. We determine the structural basis for the interaction between human ACE2 and the S protein of XBB.1.5, showing similar overall structures between the S proteins of XBB.1 and XBB.1.5. We provide the intrinsic pathogenicity of XBB.1 and XBB.1.5 in hamsters. Importantly, we find that the ORF8 nonsense mutation of XBB.1.5 resulted in impairment of MHC suppression. In vivo experiments using recombinant viruses reveal that the XBB.1.5 mutations are involved with reduced virulence of XBB.1.5. Together, our study identifies the two viral functions defined the difference between XBB.1 and XBB.1.5.

Membrane-Associated Ubiquitin Ligase RING Finger Protein 152 Orchestrates Melanogenesis via Tyrosinase Ubiquitination.

Lysosomal degradation of tyrosinase, a pivotal enzyme in melanin synthesis, negatively impacts melanogenesis in melanocytes. Nevertheless, the precise molecular mechanisms by which lysosomes target tyrosinase have remained elusive. Here, we identify RING (Really Interesting New Gene) finger protein 152 (RNF152) as a membrane-associated ubiquitin ligase specifically targeting tyrosinase for the first time, utilizing AlphaScreen technology. We observed that modulating RNF152 levels in B16 cells, either via overexpression or siRNA knockdown, resulted in decreased or increased levels of both tyrosinase and melanin, respectively. Notably, RNF152 and tyrosinase co-localized at the trans-Golgi network (TGN). However, upon treatment with lysosomal inhibitors, both proteins appeared in the lysosomes, indicating that tyrosinase undergoes RNF152-mediated lysosomal degradation. Through ubiquitination assays, we found the indispensable roles of both the RING and transmembrane (TM) domains of RNF152 in facilitating tyrosinase ubiquitination. In summary, our findings underscore RNF152 as a tyrosinase-specific ubiquitin ligase essential for regulating melanogenesis in melanocytes.

Comparative pathogenicity of SARS-CoV-2 Omicron subvariants including BA.1, BA.2, and BA.5.

The unremitting emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants necessitates ongoing control measures. Given its rapid spread, the new Omicron subvariant BA.5 requires urgent characterization. Here, we comprehensively analyzed BA.5 with the other Omicron variants BA.1, BA.2, and ancestral B.1.1. Although in vitro growth kinetics of BA.5 was comparable among the Omicron subvariants, BA.5 was much more fusogenic than BA.1 and BA.2. Airway-on-a-chip analysis showed that, among Omicron subvariants, BA.5 had enhanced ability to disrupt the respiratory epithelial and endothelial barriers. Furthermore, in our hamster model, in vivo pathogenicity of BA.5 was slightly higher than that of the other Omicron variants and less than that of ancestral B.1.1. Notably, BA.5 gains efficient virus spread compared with BA.1 and BA.2, leading to prompt immune responses. Our findings suggest that BA.5 has low pathogenicity compared with the ancestral strain but enhanced virus spread /inflammation compared with earlier Omicron subvariants.

Virological characterization of the 2022 outbreak-causing monkeypox virus using human keratinocytes and colon organoids.

The outbreak-causing monkeypox virus of 2022 (2022 MPXV) is classified as a clade IIb strain and phylogenetically distinct from prior endemic MPXV strains (clades I or IIa), suggesting that its virological properties may also differ. Here, we used human keratinocytes and induced pluripotent stem cell-derived colon organoids to examine the efficiency of viral growth in these cells and the MPXV infection-mediated host responses. MPXV replication was much more productive in keratinocytes than in colon organoids. We observed that MPXV infections, regardless of strain, caused cellular dysfunction and mitochondrial damage in keratinocytes. Notably, a significant increase in the expression of hypoxia-related genes was observed specifically in 2022 MPXV-infected keratinocytes. Our comparison of virological features between 2022 MPXV and prior endemic MPXV strains revealed signaling pathways potentially involved with the cellular damages caused by MPXV infections and highlights host vulnerabilities that could be utilized as protective therapeutic strategies against human mpox in the future.

Genetic factors affecting survival in Japanese patients with sporadic amyotrophic lateral sclerosis: a genome-wide association study and verification in iPSC-derived motor neurons from patients.

BACKGROUND: Several genetic factors are associated with the pathogenesis of sporadic amyotrophic lateral sclerosis (ALS) and its phenotypes, such as disease progression. Here, in this study, we aimed to identify the genes that affect the survival of patients with sporadic ALS. METHODS: We enrolled 1076 Japanese patients with sporadic ALS with imputed genotype data of 7 908 526 variants. We used Cox proportional hazards regression analysis with an additive model adjusted for sex, age at onset and the first two principal components calculated from genotyped data to conduct a genome-wide association study. We further analysed messenger RNA (mRNA) and phenotype expression in motor neurons derived from induced pluripotent stem cells (iPSC-MNs) of patients with ALS. RESULTS: Three novel loci were significantly associated with the survival of patients with sporadic ALS-FGF1 at 5q31.3 (rs11738209, HR=2.36 (95% CI, 1.77 to 3.15), p=4.85×10-9), THSD7A at 7p21.3 (rs2354952, 1.38 (95% CI, 1.24 to 1.55), p=1.61×10-8) and LRP1 at 12q13.3 (rs60565245, 2.18 (95% CI, 1.66 to 2.86), p=2.35×10-8). FGF1 and THSD7A variants were associated with decreased mRNA expression of each gene in iPSC-MNs and reduced in vitro survival of iPSC-MNs obtained from patients with ALS. The iPSC-MN in vitro survival was reduced when the expression of FGF1 and THSD7A was partially disrupted. The rs60565245 was not associated with LRP1 mRNA expression. CONCLUSIONS: We identified three loci associated with the survival of patients with sporadic ALS, decreased mRNA expression of FGF1 and THSD7A and the viability of iPSC-MNs from patients. The iPSC-MN model reflects the association between patient prognosis and genotype and can contribute to target screening and validation for therapeutic intervention.

Elucidation of the liver pathophysiology of COVID-19 patients using liver-on-a-chips.

SARS-CoV-2 induces severe organ damage not only in the lung but also in the liver, heart, kidney, and intestine. It is known that COVID-19 severity correlates with liver dysfunction, but few studies have investigated the liver pathophysiology in COVID-19 patients. Here, we elucidated liver pathophysiology in COVID-19 patients using organs-on-a-chip technology and clinical analyses. First, we developed liver-on-a-chip (LoC) which recapitulating hepatic functions around the intrahepatic bile duct and blood vessel. We found that hepatic dysfunctions, but not hepatobiliary diseases, were strongly induced by SARS-CoV-2 infection. Next, we evaluated the therapeutic effects of COVID-19 drugs to inhibit viral replication and recover hepatic dysfunctions, and found that the combination of anti-viral and immunosuppressive drugs (Remdesivir and Baricitinib) is effective to treat hepatic dysfunctions caused by SARS-CoV-2 infection. Finally, we analyzed the sera obtained from COVID-19 patients, and revealed that COVID-19 patients, who were positive for serum viral RNA, are likely to become severe and develop hepatic dysfunctions, as compared with COVID-19 patients who were negative for serum viral RNA. We succeeded in modeling the liver pathophysiology of COVID-19 patients using LoC technology and clinical samples.

Evaluation of Broad Anti-Coronavirus Activity of Autophagy-Related Compounds Using Human Airway Organoids.

To deal with the broad spectrum of coronaviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), that threaten human health, it is essential to not only drugs develop that target viral proteins but also consider drugs that target host proteins/cellular processes to protect them from being hijacked for viral infection and replication. To this end, it has been reported that autophagy is deeply involved in coronavirus infection. In this study, we used airway organoids to screen a chemical library of autophagic modulators to identify compounds that could potentially be used to fight against infections by a broad range of coronaviruses. Among the 80 autophagy-related compounds tested, cycloheximide and thapsigargin reduced SARS-CoV-2 infection efficiency in a dose-dependent manner. Cycloheximide treatment reduced the infection efficiency of not only six SARS-CoV-2 variants but also human coronavirus (HCoV)-229E and HCoV-OC43. Cycloheximide treatment also reversed viral infection-induced innate immune responses. However, even low-dose (1 µM) cycloheximide treatment altered the expression profile of ribosomal RNAs; thus, side effects such as inhibition of protein synthesis in host cells must be considered. These results suggest that cycloheximide has broad-spectrum anti-coronavirus activity in vitro and warrants further investigation.

Design of a chimeric ACE-2/Fc-silent fusion protein with ultrahigh affinity and neutralizing capacity for SARS-CoV-2 variants.

Background: As SARS-CoV-2 continues to mutate into Variants of Concern (VOC), there is growing and urgent need to develop effective antivirals to combat COVID-19. Monoclonal antibodies developed earlier are no longer capable of effectively neutralizing currently active VOCs. This report describes the design of variant-agnostic chimeric molecules consisting of an Angiotensin-Converting Enzyme 2 (ACE-2) domain mutated to retain ultrahigh affinity binding to a wide variety of SARS-CoV-2 variants, coupled to an Fc-silent immunoglobulin domain that eliminates antibody-dependent enhancement and extends biological half-life. Methods: Molecular modeling, Surrogate Viral Neutralization tests (sVNTs) and infection studies of human airway organoid cultures were performed with synthetic chimeras, SARS-CoV-2 spike protein mimics and SARS-CoV-2 Omicron variants B.1.1.214, BA.1, BA.2 and BA.5. Results: ACE-2 mutations L27, V34 and E90 resulted in ultrahigh affinity binding of the LVE-ACE-2 domain to the widest variety of VOCs, with KDs of 93 pM and 73 pM for binding to the Alpha B1.1.7 and Omicron B.1.1.529 variants, and notably, 78fM, 133fM and 1.81pM affinities to the Omicron BA.2, BA2.75 and BQ.1.1 subvariants, respectively. sVNT assays revealed titers of ≥4.9 ng/ml, for neutralization of recombinant viral proteins corresponding to the Alpha, Delta and Omicron variants. The values above were obtained with LVE-ACE-2/mAB chimeras containing the FcRn-binding Y-T-E sequence which extends biological half-life 3-4-fold. Conclusions: The ACE-2-mutant/Fc silent fusion proteins described have ultrahigh affinity to a wide variety of SARS-CoV-2 variants including Omicron. It is proposed that these chimeric ACE-2/mABs will constitute variant-agnostic and cost-effective prophylactics against SARS-CoV-2, particularly when administered nasally.

Upregulation of Robo4 expression by SMAD signaling suppresses vascular permeability and mortality in endotoxemia and COVID-19 models.

There is an urgent need to develop novel drugs to reduce the mortality from severe infectious diseases with the emergence of new pathogens, including Coronavirus disease 2019 (COVID-19). Although current drugs effectively suppress the proliferation of pathogens, immune cell activation, and inflammatory cytokine functions, they cannot completely reduce mortality from severe infections and sepsis. In this study, we focused on the endothelial cell-specific protein, Roundabout 4 (Robo4), which suppresses vascular permeability by stabilizing endothelial cells, and investigated whether enhanced Robo4 expression could be a novel therapeutic strategy against severe infectious diseases. Endothelial-specific overexpression of Robo4 suppresses vascular permeability and reduces mortality in lipopolysaccharide (LPS)-treated mice. Screening of small molecules that regulate Robo4 expression and subsequent analysis revealed that two competitive small mothers against decapentaplegic (SMAD) signaling pathways, activin receptor-like kinase 5 (ALK5)-SMAD2/3 and ALK1-SMAD1/5, positively and negatively regulate Robo4 expression, respectively. An ALK1 inhibitor was found to increase Robo4 expression in mouse lungs, suppress vascular permeability, prevent extravasation of melanoma cells, and decrease mortality in LPS-treated mice. The inhibitor suppressed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced endothelial barrier disruption and decreased mortality in mice infected with SARS-CoV-2. These results indicate that enhancing Robo4 expression is an efficient strategy to suppress vascular permeability and mortality in severe infectious diseases, including COVID-19, and that small molecules that upregulate Robo4 can be potential therapeutic agents against these diseases.

Exocyst complex component 2 is a potential host factor for SARS-CoV-2 infection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused an epidemic and spread rapidly all over the world. Because the analysis of host factors other than receptors and proteases has not been sufficiently performed, we attempted to identify and characterize host factors essential for SARS-CoV-2 infection using iPS cells and airway organoids (AO). Based on previous CRISPR screening and RNA-seq data, we found that exocyst complex component 2 (EXOC2) is one important host factor for SARS-CoV-2 infection. The intracellular SARS-CoV-2 nucleocapsid (N) expression level was decreased to 3.7% and the virus copy number in cell culture medium was decreased to 1.6% by EXOC2 knockdown. Consistently, immunostaining results showed that N protein-positive cells were significantly decreased by EXOC2 knockdown. We also found that EXOC2 knockdown downregulates SARS-CoV-2 infection by regulating IFNW1 expression. In conclusion, controlling the EXOC2 expression level may prevent SARS-CoV-2 infection and deserves further study.

SARS-CoV-2 disrupts respiratory vascular barriers by suppressing Claudin-5 expression.

In the initial process of coronavirus disease 2019 (COVID-19), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects respiratory epithelial cells and then transfers to other organs the blood vessels. It is believed that SARS-CoV-2 can pass the vascular wall by altering the endothelial barrier using an unknown mechanism. In this study, we investigated the effect of SARS-CoV-2 on the endothelial barrier using an airway-on-a-chip that mimics respiratory organs and found that SARS-CoV-2 produced from infected epithelial cells disrupts the barrier by decreasing Claudin-5 (CLDN5), a tight junction protein, and disrupting vascular endothelial cadherin-mediated adherens junctions. Consistently, the gene and protein expression levels of CLDN5 in the lungs of a patient with COVID-19 were decreased. CLDN5 overexpression or Fluvastatin treatment rescued the SARS-CoV-2-induced respiratory endothelial barrier disruption. We concluded that the down-regulation of CLDN5 expression is a pivotal mechanism for SARS-CoV-2-induced endothelial barrier disruption in respiratory organs and that inducing CLDN5 expression is a therapeutic strategy against COVID-19.

Therapeutic Potential of Cannabinoids on Tumor Microenvironment: A Molecular Switch in Neoplasia Transformation.

The efficacy of chemotherapy depends on the tumor microenvironment. This microenvironment consists of a complex cellular network that can exert both stimulatory and inhibitory effects on tumor genesis. Given the increasing interest in the effectiveness of cannabis, cannabinoids have gained much attention as a potential chemotherapy drug. Cannabinoids are a group of marker compounds found in Cannabis sativa L., more commonly known as marijuana, a psychoactive drug used since ancient times for pain management. Although the anticancer potential of C. sativa, has been recognized previously, increased attention was generated after discovering the endocannabinoid system and the successful production of cannabinoid receptors. In vitro and in vivo studies on various tumor models have shown therapeutic efficiency by modifying the tumor microenvironment. However, despite extensive attention regarding potential therapeutic implications of cannabinoids, considerable clinical and preclinical analysis is needed to adequately define the physiological, pharmacological, and medicinal aspects of this range of compounds in various disorders covered in this review. This review summarizes the key literature surrounding the role of cannabinoids in the tumor microenvironment and their future promise in cancer treatment.

Cell response analysis in SARS-CoV-2 infected bronchial organoids.

The development of an in vitro cell model that can be used to study severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) research is expected. Here we conducted infection experiments in bronchial organoids (BO) and an BO-derived air-liquid interface model (BO-ALI) using 8 SARS-CoV-2 variants. The infection efficiency in BO-ALI was more than 1,000 times higher than that in BO. Among the bronchial epithelial cells, we found that ciliated cells were infected with the virus, but basal cells were not. Ciliated cells died 7 days after the viral infection, but basal cells survived after the viral infection and differentiated into ciliated cells. Fibroblast growth factor 10 signaling was essential for this differentiation. These results indicate that BO and BO-ALI may be used not only to evaluate the cell response to SARS-CoV-2 and coronavirus disease 2019 (COVID-19) therapeutic agents, but also for airway regeneration studies.

Biocompatible Films of Calcium Alginate Inactivate Enveloped Viruses Such as SARS-CoV-2.

The current pandemic is urgently demanding the development of alternative materials capable of inactivating the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes the coronavirus 2019 (COVID-19) disease. Calcium alginate is a crosslinked hydrophilic biopolymer with an immense range of biomedical applications due to its excellent chemical, physical, and biological properties. In this study, the cytotoxicity and antiviral activity of calcium alginate in the form of films were studied. The results showed that these films, prepared by solvent casting and subsequent crosslinking with calcium cations, are biocompatible in human keratinocytes and are capable of inactivating enveloped viruses such as bacteriophage phi 6 with a 1.43-log reduction (94.92% viral inactivation) and SARS-CoV-2 Delta variant with a 1.64-log reduction (96.94% viral inactivation) in virus titers. The antiviral activity of these calcium alginate films can be attributed to its compacted negative charges that may bind to viral envelopes inactivating membrane receptors.

SARS-CoV-2 infection triggers paracrine senescence and leads to a sustained senescence-associated inflammatory response.

Reports of post-acute COVID-19 syndrome, in which the inflammatory response persists even after SARS-CoV-2 has disappeared, are increasing1, but the underlying mechanisms of post-acute COVID-19 syndrome remain unknown. Here, we show that SARS-CoV-2-infected cells trigger senescence-like cell-cycle arrest2,3 in neighboring uninfected cells in a paracrine manner via virus-induced cytokine production. In cultured human cells or bronchial organoids, these SASR-CoV-2 infection-induced senescent cells express high levels of a series of inflammatory factors known as senescence-associated secretory phenotypes (SASPs)4 in a sustained manner, even after SARS-CoV-2 is no longer detectable. We also show that the expression of the senescence marker CDKN2A (refs. 5,6) and various SASP factor4 genes is increased in the pulmonary cells of patients with severe post-acute COVID-19 syndrome. Furthermore, we find that mice exposed to a mouse-adapted strain of SARS-CoV-2 exhibit prolonged signs of cellular senescence and SASP in the lung at 14 days after infection when the virus was undetectable, which could be substantially reduced by the administration of senolytic drugs7. The sustained infection-induced paracrine senescence described here may be involved in the long-term inflammation caused by SARS-CoV-2 infection.

Dual inhibition of TMPRSS2 and Cathepsin Bprevents SARS-CoV-2 infection in iPS cells.

It has been reported that many receptors and proteases are required for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Although angiotensin-converting enzyme 2 (ACE2) is the most important of these receptors, little is known about the contribution of other genes. In this study, we examined the roles of neuropilin-1, basigin, transmembrane serine proteases (TMPRSSs), and cathepsins (CTSs) in SARS-CoV-2 infection using the CRISPR interference system and ACE2-expressing human induced pluripotent stem (iPS) cells. Double knockdown of TMPRSS2 and cathepsin B (CTSB) reduced the viral load to 0.036% ± 0.021%. Consistently, the combination of the CTPB inhibitor CA-074 methyl ester and the TMPRSS2 inhibitor camostat reduced the viral load to 0.0078% ± 0.0057%. This result was confirmed using four SARS-CoV-2 variants (B.1.3, B.1.1.7, B.1.351, and B.1.1.248). The simultaneous use of these two drugs reduced viral load to less than 0.01% in both female and male iPS cells. These findings suggest that compounds targeting TMPRSS2 and CTSB exhibit highly efficient antiviral effects independent of gender and SARS-CoV-2 variant.

Urine levels of the polyglutamine ataxin-3 protein are elevated in patients with spinocerebellar ataxia type 3.

INTRODUCTION: Accumulation of polyglutamine (polyQ) ataxin-3 (ATXN3) contributes to the pathobiology of spinocerebellar ataxia type 3 (SCA3). Recently, we showed that polyQ ATXN3 is elevated in the plasma and cerebrospinal fluid (CSF) of SCA3 patients, and has the potential to serve as a biological marker for this disease [1]. Based on these findings, we investigated whether polyQ ATXN3 can also be detected in urine samples from SCA3 patients. METHODS: We analyzed urine samples from 30 SCA3 subjects (including one pre-symptomatic subject), 35 subjects with other forms of ataxia, and 37 healthy controls. To quantify polyQ ATXN3 protein levels, we used our previously developed immunoassay. RESULTS: PolyQ ATXN3 can be detected in the urine of SCA3 patients, but not in urine samples from healthy controls or other forms of ataxia. There was a significant statistical association between polyQ ATXN3 levels in urine samples and those in plasma. Further, the levels of polyQ ATXN3 urine associated with an earlier age of SCA3 disease onset. CONCLUSION: As clinical trials for SCA3 advance, urine polyQ ATXN3 protein has potential to be a useful, non-invasive and inexpensive biomarker for SCA3.