Identification of residues in Lassa virus glycoprotein 1 involved in receptor switch.

Lassa virus (LASV) is an enveloped, negative-sense RNA virus that causes Lassa hemorrhagic fever. Successful entry of LASV requires the viral glycoprotein 1 (GP1) to undergo a receptor switch from its primary receptor alpha-dystroglycan (α-DG) to its endosomal receptor lysosome-associated membrane protein 1 (LAMP1). A conserved histidine triad in LASV GP1 has been reported to be responsible for receptor switch. To test the hypothesis that other non-conserved residues also contribute to receptor switch, we constructed a series of mutant LASV GP1 proteins and tested them for binding to LAMP1. Four residues, L84, K88, L107, and H170, were identified as critical for receptor switch. Substituting any of the four residues with the corresponding lymphocytic choriomeningitis virus (LCMV) residue (L84 â€‹N, K88E, L10F, and H170S) reduced the binding affinity of LASV GP1 for LAMP1. Moreover, all mutations caused decreases in glycoprotein precursor (GPC)-mediated membrane fusion at both pH 4.5 and 5.2. The infectivity of pseudotyped viruses bearing either GPCL84N or GPCK88E decreased sharply in multiple cell types, while L107F and H170S had only mild effects on infectivity. Using biolayer light interferometry assay, we found that all four mutants had decreased binding affinity to LAMP1, in the order of binding affinity being L84 â€‹N â€‹> â€‹L107F â€‹> â€‹K88E â€‹> â€‹H170S. The four amino acid loci identified for the first time in this study have important reference significance for the in-depth investigation of the mechanism of receptor switching and immune escape of LASV occurrence and the development of reserve anti-LASV infection drugs.

Endoscopic Dyeing and Plasma Coblation-Assisted Open Neck Surgery for Pyriform Fossa Branchial Apparatus Anomalies in Adults.

Objective: Pyriform fossa (PF) branchial apparatus anomalies (PFBAA) are rare congenital third or fourth branchial apparatus anomalies (TBAA or FBAA). This article summarizes our paradigm in managing this condition by combining endoscopic procedures and open neck surgery. Methods: A retrospective review was undertaken concerning PFBAA cases treated at our tertiary medical institution between July 2020 and November 2023. Data were collected from case records. Three sequential steps were implemented: (1) direct laryngoscopy to identify internal orifice (IO), with injection of methylene blue into it; (2) open neck surgery to resect all inflammatory tissues, focusing on the ligation of the sinus tract out of PF; and (3) plasma coblation of IO mucosa. Results: In total, 7 cases (4 men and 3 women) were included (28-67 years old, median age 53). Presenting symptoms were various, with 6 lesions on the left and 1 on the right side. Preoperative (PO) fiberoptic laryngoscopy identified IO in 6 patients, while PO barium esophageal study identified outflow from PF in 4 patients. A preliminary diagnosis of PFBAA could be established in all cases (2 TBAA and 5 FBAA cases). Direct laryngoscopy after general anesthesia identified IO in all cases (2 on the base of PF and 5 on the apex of PF). All the surgical procedures were successful, with uneventful recovery in all the patients. No postoperative complications were observed. All the patients resumed oral fluid intake after confirmation of no pharyngeal fistula by barium esophageal study on the seventh postoperative day. The duration of follow-up was between 6 and 40 months (with a median duration of 27 months). No recurrence was observed. Conclusion: Open neck surgery, assisted by endoscopic dyeing of sinus tracts and plasma coblation of IO mucosa, is a suitable treatment for PFBAA in adults. This paradigm is effective and safe for senior surgeons.

Long-term immune response to Omicron-specific mRNA vaccination in mice, hamsters, and nonhuman primates.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron and its subvariants (such as BQ.1, XBB and the latest variants, including XBB.1.16, EG.5, and BA.2.86), as the dominant variants, currently account for almost all new infections in the world due to their high transmissibility and immune escape ability. Omicron-specific mRNA vaccines showed great potential to protect against Omicron infections. However, whether the vaccine could provide long-term protection is unknown. Toward this goal, we evaluated the immunogenicity of a preclinical Omicron (BA.1)-specific mRNA vaccine (SOmicron-6P) in different animal models. SOmicron-6P induced the highest levels of antibody titers at 1-2 weeks in different animals after the second dose. Even 9 months after the immunization, we observed modest neutralizing activity against Omicron subvariants in macaques. In addition, immunological memory cells can be rapidly reactivated upon stimulation. SOmicron-6P at concentrations higher than 10 µg effectively protected hamsters from BA.1 challenge 253 days after the first immunization, which could be attributed to the reactivation of immune systems. In addition, the toxicity tests conducted in rats revealed a highly favorable biosafety profile for SOmicron-6P, even at high dosages. Our data suggest that the Omicron-specific mRNA vaccine is highly effective and safe in animal models and provides long-term immunologic protection against SARS-CoV-2 Omicron infections.

An engineered bispecific nanobody in tetrameric secretory IgA format confers broad neutralization against SARS-CoV-1&2 and most variants.

SARS-CoV-2, a type of respiratory virus, has exerted a great impact on global health and economy over the past three years. Antibody-based therapy was initially successful but later failed due to the accumulation of mutations in the spike protein of the virus. Strategies that enable antibodies to resist virus escape are therefore of great significance. Here, we engineer a bispecific SARS-CoV-2 neutralizing nanobody in secretory Immunoglobulin A (SIgA) format, named S2-3-IgA2m2, which shows broad and potent neutralization against SARS-CoV-1, SARS-CoV-2 and its variants of concern (VOCs) including XBB and BQ.1.1. S2-3-IgA2m2 is ∼1800-fold more potent than its parental IgG counterpart in neutralizing XBB. S2-3-IgA2m2 is stable in mouse lungs at least for three days when administrated by nasal delivery. In hamsters infected with BA.5, three intranasal doses of S2-3-IgA2m2 at 1 mg/kg significantly reduce viral RNA loads and completely eliminate infectious particles in the trachea and lungs. Notably, even at single dose of 1 mg/kg, S2-3-IgA2m2 prophylactically administered through the intranasal route drastically reduces airway viral RNA loads and infectious particles. This study provides an effective weapon combating SARS-CoV-2, proposes a new strategy overcoming the virus escape, and lays strategic reserves for rapid response to potential future outbreaks of "SARS-CoV-3".

Development of a zinc(II) 2-pyridinecarboxaldehyde thiosemicarbazone complex with remarkable antitumor and antiangiogenic activities.

To develop the next-generation metal agents for efficiently inhibiting tumor growth, we synthesized a series of new Zn(II) complexes (C1-C5) derived from 2-pyridinecarboxaldehyde thiosemicarbazone and investigated their structure-activity relationships. C5 bearing two methyl groups at the N-4 position of the ligand exerted the strongest inhibition effect among all the Zn(II) complexes. Importantly, C5 exerted an effective inhibitory effect on tumor growth and produced few side effects in vivo. We further confirmed the antitumor mechanisms of C5, including arresting the cell cycle at the S phase, inducing apoptosis, inducing lethal autophagy, and suppressing angiogenesis.

How growth mindset influences mathematics achievements: A study of Chinese middle school students.

Introduction: It has been suggested that students with growth mindsets are more likely to achieve better mathematics learning results than their counterparts with fixed mindsets. However, inconsistent and some even contradictory results have been reported in recent studies which examined the associations between growth mindset and mathematics achievements, suggesting the complexity regarding the effects of growth mindset on academic achievements. Methods: This study aims to examine students' growth mindsets, failure attributions, intrinsic motivation, mathematics self-efficacy, mathematics anxiety and mathematics achievements in one model to capture the sophisticated functioning processes of growth mindset. A total number of 266 middle school students in China participated in this study. Students' mindset and related variables (i.e.,motivations to learn mathematics, attributions of failure in mathematics, mathematics anxiety, mathematics self-efficacy) were measured at year 7, the first year of junior middle school in China. These students' mathematics learning outcomes were tracked from year 7 to year 9, the end of junior middle school. Structural equation modeling (SEM) was used to investigate the relations among students' growth mindsets, failure attributions, intrinsic motivation, mathematics self-efficacy, mathematics anxiety and mathematics achievements. Results: The results show that: (1) growth mindset doesn't directly predict mathematics achievements; (2) growth mindset indirectly influences mathematics achievements through intrinsic motivation; (3) failure attributions and mathematics self-efficacy sequentially mediate the association between growth mindset mathematics achievements; (4) failure attributions and mathematics anxiety sequentially mediate the relationship between growth mindset mathematics achievements. Discussion: The results of this study contribute a better understanding about how growth mindsets make impacts on middle school students' mathematics achievements. These findings have important implications for mathematics education in that we could not simply cultivate students' growth mindset in schools with expectations of higher mathematics learning outcomes. Instead, along with the growth mindset intervention, it is fundamental to make interventions on students' intrinsic motivation, failure attribution, mathematics self-efficacy, and mathematics anxiety in mathematics teaching and learning.

Deletion of the first glycosylation site promotes Lassa virus glycoprotein-mediated membrane fusion.

The Lassa virus (LASV) is endemic in West Africa and causes severe hemorrhagic Lassa fever in humans. The glycoprotein complex (GPC) of LASV is highly glycosylation-modified, with 11 â€‹N-glycosylation sites. All 11 N-linked glycan chains play critical roles in GPC cleavage, folding, receptor binding, membrane fusion, and immune evasion. In this study, we focused on the first glycosylation site because its deletion mutant (N79Q) results in an unexpected enhanced membrane fusion, whereas it exerts little effect on GPC expression, cleavage, and receptor binding. Meanwhile, the pseudotype virus bearing GPCN79Q was more sensitive to the neutralizing antibody 37.7H and was attenuated in virulence. Exploring the biological functions of the key glycosylation site on LASV GPC will help elucidate the mechanism of LASV infection and provide strategies for the development of attenuated vaccines against LASV infection.

Developing Next-Generation Protein-Based Vaccines Using High-Affinity Glycan Ligand-Decorated Glyconanoparticles.

Major diseases, such as cancer and COVID-19, are frightening global health problems, and sustained action is necessary to develop vaccines. Here, for the first time, ethoxy acetalated dextran nanoparticles (Ace-Dex-NPs) are functionalized with 9-N-(4H-thieno[3,2-c]chromene-2-carbamoyl)-Siaα2-3Galß1-4GlcNAc (TCC Sia-LacNAc) targeting macrophages as a universal vaccine design platform. First, azide-containing oxidized Ace-Dex-NPs are synthesized. After the NPs are conjugated with ovalbumin (OVA) and resiquimod (Rd), they are coupled to TCC Sia-LacNAc-DBCO to produce TCC Sia-Ace-Dex-OVA-Rd, which induce a potent, long-lasting OVA-specific cytotoxic T-lymphocyte (CTL) response and high anti-OVA IgG, providing mice with superior protection against tumors. Next, this strategy is exploited to develop vaccines against infection by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein is the main target for neutralizing antibodies. The TCC Sia-Ace-Dex platform is preferentially used for designing an RBD-based vaccine. Strikingly, the synthetic TCC Sia-Ace-Dex-RBD-Rd elicited potent RBD-neutralizing antibodies against live SARS-CoV-2 infected Vero E6 cells. To develop a universal SARS-CoV-2 vaccine, the TCC Sia-Ace-Dex-N-Rd vaccine carrying SARS-CoV-2 nucleocapsid protein (N) is also prepared, which is highly conserved among SARS-CoV-2 and its variants of concern (VOCs), including Omicron (BA.1 to BA.5); this vaccine can trigger strong N-specific CTL responses against target cells infected with SARS-CoV-2 and its VOCs.

Analysis of ischemic stroke burden in Asia from 1990 to 2019: based on the global burden of disease 2019 data.

Background: Ischemic stroke has the characteristics of high morbidity, mortality, and recurrence rate. This study aimed to describe and assess the burden of ischemic stroke in Asia based on the global burden of disease (GBD) 2019 data and provide a crucial scientific foundation for the prevention and control of this life-threatening disease. Method: This study used the GBD 2019 data to assess the burden of ischemic stroke. The indicators used in this study were derived from the following methods: (i) the incidence of ischemic stroke was estimated using the disability model for the global burden of disease study-mixed effects regression (DisMod-MR), a Bayesian meta-regression disease modeling tool; (ii) the non-specific codes of all available data on mortality were corrected and used to estimate mortality rates for ischemic stroke and the cause of death ensemble model was used to estimate mortality rates; and (iii) the disability-adjusted life years (DALYs) is the sum of years lived with disability (YLD) and the years of life lost (YLL), which quantifies the health loss due to specific diseases and injuries. In addition, the joinpoint regression model was adopted to analyze the temporal trend of ischemic stroke from 1990 to 2019 in Asia. Result: This study found an increase in the burden of ischemic stroke in 2019 compared to 1990. Moreover, the age-standardized incidence rate (ASIR) of ischemic stroke showed a gradual upward trend over the specific period. The age-standardized mortality rate (ASMR) showed a downward trend in Asia from 1990 to 2019. The burden of ischemic stroke was more concentrated on older age groups, particularly those older than 65 years. East Asia had the highest burden of ischemic stroke compared to other regions in Asia. Particularly, China, India, Indonesia, and Japan had the highest burdens of ischemic stroke among the Asian countries and regions. However, the population with the highest burden of ischemic stroke was still the elderly group. Conclusion: Based on our study, it is evident that the burden of ischemic stroke exists substantially and exhibits variations in the aspects of age, gender, and geographical region in Asia. Without targeted implementation of population-wide primary strategies for prevention and control, the burden of ischemic stroke is likely to worsen significantly in the future.

Screening and Identification of Lassa Virus Entry Inhibitors from a Fragment-Based Drug Discovery Library.

Lassa virus (LASV) is a highly pathogenic virus that is categorized as a biosafety level-4 pathogen. Currently, there are no approved drugs or vaccines specific to LASV. In this study, high-throughput screening of a fragment-based drug discovery library was performed against LASV entry using a pseudotype virus bearing the LASV envelope glycoprotein complex (GPC). Two compounds, F1920 and F1965, were identified as LASV entry inhibitors that block GPC-mediated membrane fusion. Analysis of adaptive mutants demonstrated that the transient mutants L442F and I445S, as well as the constant mutant F446L, were located on the same side on the transmembrane domain of the subunit GP2 of GPC, and all the mutants conferred resistance to both F1920 and F1965. Furthermore, F1920 antiviral activity extended to other highly pathogenic mammarenaviruses, whereas F1965 was LASV-specific. Our study showed that both F1920 and F1965 provide a potential backbone for the development of lead drugs for preventing LASV infection.

Bergamottin, a bioactive component of bergamot, inhibits SARS-CoV-2 infection in golden Syrian hamsters.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused an ongoing pandemic, coronavirus disease-2019 (COVID-19), which has become a major global public health event. Antiviral compounds remain the predominant means of treating COVID-19. Here, we reported that bergamottin, a furanocoumarin originally found in bergamot, exhibited inhibitory activity against SARS-CoV-2 in vitro, ex vivo, and in vivo. Bergamottin interfered with multiple stages of virus life cycles, specifically blocking the SARS-CoV-2 spike-mediated membrane fusion and effectively reducing viral RNA synthesis. Oral delivery of bergamottin to golden Syrian hamsters at dosages of both 50 mg/kg and 75 mg/kg reduced the SARS-CoV-2 load in nasal turbinates and lung tissues. Pathological damage caused by viral infection was also ameliorated after bergamottin treatment. Overall, our study provides evidence of bergamottin as a promising natural compound, with broad-spectrum anti-coronavirus activity, that could be further developed in the fight against COVID-19 infection during the current pandemic.

Highly selective cross-coupling reactions of 1,1-dibromoethylenes with alkynylaluminums for the synthesis of aryl substituted conjugated enediynes and unsymmetrical 1,3-diynes.

A highly efficient method for the synthesis of aryl substituted conjugated enediynes and unsymmetrical 1,3-diynes via selective cross-coupling reactions of 1,1-dibromoethylenes with alkynylaluminums using the Pd(OAc)2-DPPE and Pd2(dba)3-TFP complexes as catalysts, respectively, has been successfully developed. Though the alkyl substituted conjugated enediynes and unsymmetrical 1,3-diynes were not obtained, this case is also remarkable as the same starting materials could selectively produce either aryl substituted conjugated enediynes or unsymmetrical 1,3-diynes in moderate to excellent yields (up to 99%) in the different Pd-phosphine catalytic systems.

Isolated complete dislocation of hamate bone with an ulnar nerve injury: a case report and literature review.

Background: Isolated complete dislocation of the hamate bone is a rare wrist injury. Only 22 cases have been reported in the literature. Four of them were associated with nerve injury, but it is a pity that the causes of ulnar nerve injury had never been deeply analyzed. In the case report, it was stated that the ulnar nerve injury was caused by both displacement of uncinate bone and change of position of transverse carpal ligament. The complete dislocation of the hamate bone is mostly caused by direct force, often accompanied by tears of the surrounding ligaments. Case Description: A 30-year-old woman was treated because her left hand was crushed by a machine roller. Plain film X-ray showed isolated dislocation of the volar hamate and rotation of the hamate bone to the volar side. Clinical manifestations and computed tomography (CT) signs suggest ulnar nerve injury. The patient was quickly transported to the operating room for open reduction and internal fixation of the hamate bone and repair of the dorsal carpal ligament. The patient fully recovered after 12 months. Conclusions: Isolated complete dislocation of the hamate bone is a rare injury. The most common cause is direct compression force to the wrist. Diagnosis can be made through review of the patient's medical history, physical examination and X-ray, however, CT can accurately evaluate the displacement and rotation of the hamate bone, hamate bone fracture and other concomitant wrist fractures, suggesting compression changes of the median nerve and ulnar nerve to provide a reliable basis for the formulation of a clinical care plan. The case report added the evidence-based practice, and discussed the anatomical mechanism and imaging manifestation of ulnar nerve injury associated with complete dislocation of hamate bone.

Dithiocarbazate-FeIII, -CoIII, -NiII, and -ZnII Complexes: Design, Synthesis, Structure, and Anticancer Evaluation.

Non-platinum-metal complexes show great potential as anticancer agents. Herein, a series of dithiocarbazate non-Pt-metal complexes, including [FeIII(L)2]·Cl·2H2O 1, [CoIII(L)2]·NO3·2.5H2O 2, [NiII(L)2] 3, and [ZnII(L)2] 4, have been designed and evaluated for their efficacy as antineoplastic agents. Among them, complex 2 exhibited higher anticancer efficacy than complexes 1, 3, 4, and cisplatin against several cancer cell lines. Hemolysis assays revealed that complex 2 showed comparable hemolysis with cisplatin. In vivo anticancer evaluations showed that complex 2 could retard tumor xenograft growth effectively with low systemic toxicity. Further studies revealed that complex 2 suppressed cancer cells by triggering multiple mechanisms involving the simultaneous inhibition of mitochondria and glycolytic bioenergetics. Overall, our study provides new insights into the anticancer mechanism of Co complexes, which can be used as a good strategy to overcome the flexibility of cancer cells to chemotherapy adaptation.

Screening of Botanical Drugs against SARS-CoV-2 Entry Reveals Novel Therapeutic Agents to Treat COVID-19.

An escalating pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has severely impacted global health. There is a severe lack of specific treatment options for diseases caused by SARS-CoV-2. In this study, we used a pseudotype virus (pv) containing the SARS-CoV-2 S glycoprotein to screen a botanical drug library containing 1037 botanical drugs to identify agents that prevent SARS-CoV-2 entry into the cell. Our study identified four hits, including angeloylgomisin O, schisandrin B, procyanidin, and oleanonic acid, as effective SARS-CoV-2 S pv entry inhibitors in the micromolar range. A mechanistic study revealed that these four agents inhibited SARS-CoV-2 S pv entry by blocking spike (S) protein-mediated membrane fusion. Furthermore, angeloylgomisin O and schisandrin B inhibited authentic SARS-CoV-2 with a high selective index (SI; 50% cytotoxic concentration/50% inhibition concentration). Our drug combination studies performed in cellular antiviral assays revealed that angeloylgomisin O has synergistic effects in combination with remdesivir, a drug widely used to treat SARS-CoV-2-mediated infections. We also showed that two hits could inhibit the newly emerged alpha (B.1.1.7) and beta (B.1.351) variants. Our findings collectively indicate that angeloylgomisin O and schisandrin B could inhibit SARS-CoV-2 efficiently, thereby making them potential therapeutic agents to treat the coronavirus disease of 2019.

Screening and identification of Lassa virus endonuclease-targeting inhibitors from a fragment-based drug discovery library.

Lassa virus (LASV) belongs to the Old World genus Mammarenavirus, family Arenaviridae, and order Bunyavirales. Arenavirus contains a segmented negative-sense RNA genome, which is in line with the bunyavirus and orthomyxoviruses. The segmented negative-sense RNA viruses utilize a cap-snatching strategy to provide primers cleavaged from the host capped mRNA for viral mRNA transcription. As a similar strategy and the conformational conservation shared with these viruses, the endonuclease (EN) would serve as an attractive target for developing broad-spectrum inhibitors. Using the LASV minigenome (MG) system, we screened a fragment-based drug discovery library and found that two hits, F1204 and F1781, inhibited LASV MG activity. Both hits also inhibited the prototype arenavirus Lymphocytic choriomeningitis virus (LCMV) MG activity. Furthermore, both hits effectively inhibited authentic LCMV and severe fever with thrombocytopenia syndrome virus (SFTSV) infections. Similarly, both hits could inhibit the activity of LASV, LCMV, and SFTSV EN. The combination of either compound with an arenavirus entry inhibitor had significant synergistic antiviral effects. Moreover, both hits were found to be capable of binding to LASV EN with a binding affinity at the micromolar level. These findings provide a basis for developing the hits as potential candidates for the treatment of segmented negative-sense RNA virus infections.

Cost-effectiveness of tildrakizumab for the treatment of moderate-to-severe psoriasis in the United States.

OBJECTIVE: To evaluate the relative cost-effectiveness of tildrakizumab and other biologic and targeted systemic treatments compared with a mix of topical therapies, phototherapies, and other conventional systemic therapies as first-line treatment for moderate-to-severe plaque psoriasis from a United States payer's perspective. METHODS: A Markov model consisting of health states based on Psoriasis Area Severity Index (PASI) response rate categories and death was developed. The probabilities of achieving PASI responses were derived from a network meta-analysis based on published efficacy data. Health care costs and effectiveness measured in quality-adjusted life-years (QALYs) were estimated. Incremental costs per QALY gained of each biologic/targeted first-line treatment versus a mix of conventional treatments were compared to provide relative cost-effectiveness among biologic and targeted first-line treatments. RESULTS: Over 10 years, the incremental cost per QALY gained compared with a mix of topical therapies, phototherapies, and other oral systemic therapies was lowest for brodalumab, infliximab, apremilast, and tildrakizumab, followed by secukinumab, ixekizumab, guselkumab, adalimumab, ustekinumab, and etanercept. The position of tildrakizumab relative to the other treatments remained the same across multiple scenarios. CONCLUSIONS: Tildrakizumab is among the most cost-effective first-line therapies for moderate-to-severe plaque psoriasis and is more cost-effective than secukinumab, ixekizumab, guselkumab, adalimumab, ustekinumab, and etanercept.

Screening and Identification of Lujo Virus Entry Inhibitors From an Food and Drug Administration-Approved Drugs Library.

Lujo virus (LUJV) belongs to the Old World (OW) genus Mammarenavirus (family Arenaviridae). It is categorized as a biosafety level (BSL) 4 agent. Currently, there are no U.S. Food and Drug Administration (FDA)-approved drugs or vaccines specifically for LUJV or other pathogenic OW mammarenaviruses. Here, a high-throughput screening of an FDA-approved drug library was conducted using pseudotype viruses bearing LUJV envelope glycoprotein (GPC) to identify inhibitors of LUJV entry. Three hit compounds, trametinib, manidipine, and lercanidipine, were identified as LUJV entry inhibitors in the micromolar range. Mechanistic studies revealed that trametinib inhibited LUJV GPC-mediated membrane fusion by targeting C410 [located in the transmembrane (TM) domain], while manidipine and lercanidipine inhibited LUJV entry by acting as calcium channel blockers. Meanwhile, all three hits extended their antiviral spectra to the entry of other pathogenic mammarenaviruses. Furthermore, all three could inhibit the authentic prototype mammarenavirus, lymphocytic choriomeningitis virus (LCMV), and could prevent infection at the micromolar level. This study shows that trametinib, manidipine, and lercanidipine are candidates for LUJV therapy and highlights the critical role of calcium in LUJV infection. The presented findings reinforce the notion that the key residue(s) located in the TM domain of GPC provide an entry-targeted platform for designing mammarenavirus inhibitors.

Mechanism through Which Retrocyclin Targets Flavivirus Multiplication.

Currently, there are no approved drugs for the treatment of flavivirus infection. Accordingly, we tested the inhibitory effects of the novel θ-defensin retrocyclin-101 (RC-101) against flavivirus infection and investigated the mechanism underlying the potential inhibitory effects. First, RC-101 robustly inhibited both Japanese encephalitis virus (JEV) and Zika virus (ZIKV) infections. RC-101 exerted inhibitory effects on the entry and replication stages. Results also indicated that the nonstructural protein NS2B-NS3 serine protease might serve as a potential viral target. Furthermore, RC-101 inhibited protease activity at the micromolar level. We also demonstrated that with respect to the glycoprotein E protein of flavivirus, the DE loop of domain III (DIII), which is the receptor-binding domain of the E protein, might serve as another viral target of RC-101. Moreover, a JEV DE mutant exhibited resistance to RC-101, which was associated with deceased binding affinity of RC-101 to DIII. These findings provide a basis for the development of RC-101 as a potential candidate for the treatment of flavivirus infection. IMPORTANCE Retrocyclin is an artificially humanized circular θ-defensin peptide, containing 18 residues, previously reported to possess broad antimicrobial activity. In this study, we found that retrocyclin-101 inhibited flavivirus (ZIKV and JEV) infections. Retrocyclin-101 inhibited NS2B-NS3 serine protease activity, suggesting that the catalytic triad of the protease is the target. Moreover, retrocyclin-101 bound to the DE loop of the E protein of flavivirus, which prevented its entry.