Therapeutic stapled peptides: Efficacy and molecular targets.

Peptide stapling, by employing a stable, preformed alpha-helical conformation, results in the production of peptides with improved membrane permeability and enhanced proteolytic stability, compared to the original peptides, and provides an effective solution to accelerate the rapid development of peptide drugs. Various reviews present peptide stapling chemistries, anchoring residues and one- or two-component cyclization, however, therapeutic stapled peptides have not been systematically summarized, especially focusing on various disease-related targets. This review highlights the latest advances in therapeutic peptide drug development facilitated by the application of stapling technology, including different stapling techniques, synthetic accessibility, applicability to biological targets, potential for solving biological problems, as well as the current status of development. Stapled peptides as therapeutic drug candidates have been classified and analysed mainly by receptor- and ligand-based stapled peptide design against various diseases, including cancer, infectious diseases, inflammation, and diabetes. This review is expected to provide a comprehensive reference for the rational design of stapled peptides for different diseases and targets to facilitate the development of therapeutic peptides with enhanced pharmacokinetic and biological properties.

All-hydrocarbon stapling enables improvement of antimicrobial activity and proteolytic stability of peptide Figainin 2.

Figainin 2 is a cationic, hydrophobic, α-helical host-defense peptide with 28 residues, which was isolated from the skin secretions of the Chaco tree frog. It shows potent inhibitory activity against both Gram-negative and Gram-positive pathogens and has garnered considerable interest in developing novel classes of natural antibacterial agents. However, as a linear peptide, conformational flexibility and poor proteolytic stability hindered its development as antibacterial agent. To alleviate its susceptibility to proteolytic degradation and improve its antibacterial activity, a series of hydrocarbon-stable analogs of Figainin 2 were synthesized and evaluated for their secondary structure, protease stability, antimicrobial, and hemolytic activities. Among them, F2-12 showed significant improvement in protease resistance and antimicrobial activity compared to that of the template peptide. This study provides a promising strategy for the development of antimicrobial drugs.

Efficacy, immunogenicity and safety of respiratory syncytial virus prefusion F vaccine: systematic review and meta-analysis.

OBJECTIVE: A notable research gap exists in the systematic review and meta-analysis concerning the efficacy, immunogenicity, and safety of the respiratory syncytial virus (RSV) prefusion F vaccine. METHODS: We conducted a comprehensive search across PubMed, Embase, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov to retrieve articles related to the efficacy, immunogenicity, and safety of RSV prefusion F vaccines, published through September 8, 2023. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. RESULTS: A total of 22 randomized controlled trials involving 78,990 participants were included in this systematic review and meta-analysis. The RSV prefusion F vaccine exhibited a vaccine effectiveness of 68% (95% CI: 59-75%) against RSV-associated acute respiratory illness, 70% (95% CI: 60-77%) against medically attended RSV-associated lower respiratory tract illness, and 87% (95% CI: 71-94%) against medically attended severe RSV-associated lower respiratory tract illness. Common reported local adverse reactions following RSV prefusion F vaccination include pain, redness, and swelling at the injection site, and systemic reactions such as fatigue, headache, myalgia, arthralgia, nausea, and chills. CONCLUSIONS: Our meta-analysis suggests that vaccines using the RSV prefusion F protein as antigen exhibit appears broadly acceptable efficacy, immunogenicity, and safety in the population. In particular, it provides high protective efficiency against severe RSV-associated lower respiratory tract disease.

LncRNA ENST00000370438 promotes cell proliferation by upregulating DHCR24 in breast cancer.

Long noncoding RNAs (lncRNAs) are critically involved in the occurrence and development of breast cancer (BC). In this study, we performed RNA sequencing, and the results revealed an increase in the expression level of novel lncRNA ENST00000370438 in tissues of patients with BC. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) results showed an increase in lncRNA ENST00000370438 expression level in 23 pairs of BC tissues. Next, we determined the effect of ENST00000370438 on BC cell proliferation, and the results showed that ENST00000370438 promotes cell proliferation in BC. The proteomic analysis showed a decrease in DHCR24 expression level in BC cells transfected with ENST00000370438 small interfering RNA. Western blot and qRT-PCR assay results showed that ENST00000370438 regulated DHCR24 expression. Furthermore, the rescue experiment showed that the interference with ENST00000370438 expression could restore the effect of DHCR24 overexpression on BC cell proliferation, demonstrating that ENST00000370438 could promote cell proliferation by upregulating DHCR24. Finally, we showed that lncRNA ENST000000370438 could promote tumor growth by overexpressing DHCR24 in nude mice. Our results demonstrated that lncRNA ENST00000370438 promotes BC cell proliferation by upregulating DHCR24 expression.

Emergence, Evolution, and Pathogenicity of Influenza A(H7N4) Virus in Shorebirds in China.

A 2-year surveillance study of influenza A viruses in migratory birds was conducted to understand the subsequent risk during the migratory seasons in Dandong Yalu River Estuary Coastal Wetland National Nature Reserve, Liaoning Province, China, a major stopover site on the East Asian-Australasian flyway. Overall, we isolated 27 influenza A viruses with multiple subtypes, including H3N8 (n = 2), H4N6 (n = 2), H4N7 (n = 2), H7N4 (n = 9), H7N7 (n = 1), H10N7 (n = 7), and H13N6 (n = 4). Particularly, a novel reassortant influenza A(H7N4) virus was first identified in a woman and her backyard poultry flock in Jiangsu Province, China, posing a serious threat to public health. Here, we describe the genetic characterization and pathogenicity of the nine influenza A(H7N4) isolates. Phylogenetic analysis indicated that complex viral gene flow occurred among Asian countries. We also demonstrated a similar evolutionary trajectory of the surface genes of the A(H7N4) isolates and Jiangsu human-related A(H7N4) viruses. Our A(H7N4) isolates exhibited differing degrees of virulence in mice, suggesting a potential risk to other mammalian species, including humans. We revealed multiple mutations that might affect viral virulence in mice. Our report highlights the importance and need for the long-term surveillance of avian influenza virus in migratory birds combined with domestic poultry surveillance along migratory routes and flyways and, thereby, the development of measures to manage potential health threats. IMPORTANCE The H7 subtype avian influenza viruses, such as H7N2, H7N3, H7N4, H7N7, and H7N9, were documented as being capable of infecting humans, and the H7 subtype low pathogenicity avian influenza viruses are capable of mutating into highly pathogenic avian influenza; therefore, they pose a serious threat to public health. Here, we investigated the evolutionary history, molecular characteristics, and pathogenicity of shorebird-origin influenza A(H7N4) viruses, showing a similar evolutionary trajectory with Jiangsu human A(H7N4) viruses in HA and NA genes. Moreover, our isolates exhibited variable virulence (including moderate virulence) in mice, suggesting a potential risk to other mammalian species, including humans.

lncRNA ENST00000422059 promotes cell proliferation and inhibits cell apoptosis in breast cancer by regulating the miR-145-5p/KLF5 axis.

Krüppel-like zinc-finger transcription factor 5 (KLF5) is a vital regulator of breast cancer (BC) onset and progression. The mechanism by which KLF5 regulates BC is still not clearly known. In this study, bioinformatics analysis shows that BC-affected individuals with elevated KLF5 expression levels have poor clinical outcomes. We further verify that miR-145-5p regulated KLF5 expression to promote cell apoptosis and inhibit cell proliferation in BC via dual-luciferase reporter assay, western blot analysis, qRT-PCR, CCK-8 assay and cell apoptosis assay. In addition, based on bioinformatics analysis, the binding of ENST00000422059 with miR-145-5p is confirmed by dual-luciferase reporter assay. Subsequently, FISH, western blot analysis, qRT-PCR, CCK-8 and cell apoptosis assays verified that ENST00000422059 increases KLF5 protein expression by sponging miRNA to promote cell proliferation and inhibit cell apoptosis. Finally, ENST00000422059 is found to accelerate tumor progression by regulating the miR-145-5p/KLF5 axis in vivo. In conclusion, this study suggests that ENST00000422059 upregulates KLF5 by sponging miR-145-5p to promote BC progression.

Total Chemical Synthesis of Correctly Folded Disulfide-Rich Proteins Using a Removable O-Linked ß-N-Acetylglucosamine Strategy.

Disulfide-rich proteins are useful as drugs or tool molecules in biomedical studies, but their synthesis is complicated by the difficulties associated with their folding. Here, we describe a removable glycosylation modification (RGM) strategy that expedites the chemical synthesis of correctly folded proteins with multiple or even interchain disulfide bonds. Our strategy comprises the introduction of simple O-linked ß-N-acetylglucosamine (O-GlcNAc) groups at the Ser/Thr sites that effectively improve the folding of disulfide-rich proteins by stabilization of their folding intermediates. After folding, the O-GlcNAc groups can be efficiently removed using O-GlcNAcase (OGA) to afford the correctly folded proteins. Using this strategy, we completed the synthesis of correctly folded hepcidin, an iron-regulating hormone bearing four pairs of disulfide-bonds, and the first total synthesis of correctly folded interleukin-5 (IL-5), a 26 kDa homodimer cytokine responsible for eosinophil growth and differentiation.

Comparison of different strategies towards the chemical synthesis of long-chain scorpion toxin AaH-II.

Long-chain scorpion toxin AaH-II isolated from Androctonus australis Hector can selectively inhibit mammalian voltage-gated sodium ion channel Nav 1.7 responsible for pain sensation. Efficient chemical synthesis of AaH-II and its derivatives is beneficial to the study of the function and mechanism of Nav 1.7 and the development of potential peptide inhibitors. Herein, we compared three different strategies, namely, direct solid-phase peptide synthesis, hydrazide-based two-segment native chemical ligation, and hydrazide-based three-segment native chemical ligation for the synthesis of AaH-II. The hydrazide-based two-segment native chemical ligation affords the target toxin with the optimal efficiency, which provides a practically robust procedure for the preparation of tool molecules derived from AaH-II to study the biological functions and modulation of Nav 1.7. Our work highlights the importance of selecting suitable segment condensation approach in the chemical synthesis of protein toxins.

Chemical Synthesis of a Full-Length G-Protein-Coupled Receptor ß2-Adrenergic Receptor with Defined Modification Patterns at the C-Terminus.

The ß2-adrenergic receptor (ß2AR) is a G-protein-coupled receptor (GPCR) that responds to the hormone adrenaline and is an important drug target in the context of respiratory diseases, including asthma. ß2AR function can be regulated by post-translational modifications such as phosphorylation and ubiquitination at the C-terminus, but access to the full-length ß2AR with well-defined and homogeneous modification patterns critical for biochemical and biophysical studies remains challenging. Here, we report a practical synthesis of differentially modified, full-length ß2AR based on a combined native chemical ligation (NCL) and sortase ligation strategy. An array of homogeneous samples of full-length ß2ARs with distinct modification patterns, including a full-length ß2AR bearing both monoubiquitination and octaphosphorylation modifications, were successfully prepared for the first time. Using these homogeneously modified full-length ß2AR receptors, we found that different phosphorylation patterns mediate different interactions with ß-arrestin1 as reflected in different agonist binding affinities. Our experiments also indicated that ubiquitination can further modulate interactions between ß2AR and ß-arrestin1. Access to full-length ß2AR with well-defined and homogeneous modification patterns at the C-terminus opens a door to further in-depth mechanistic studies into the structure and dynamics of ß2AR complexes with downstream transducer proteins, including G proteins, arrestins, and GPCR kinases.

Early Use of Corticosteroid May Prolong SARS-CoV-2 Shedding in Non-Intensive Care Unit Patients with COVID-19 Pneumonia: A Multicenter, Single-Blind, Randomized Control Trial.

BACKGROUND: There is still no clinical evidence available to support or to oppose corticosteroid treatment for coronavirus disease 2019 (COVID-19) pneumonia. OBJECTIVE: To investigate the efficacy and safety of corticosteroid given to the hospitalized patients with COVID-19 pneumonia. METHODS: This was a prospective, multicenter, single-blind, randomized control trial. Adult patients with COVID-19 pneumonia who were admitted to the general ward were randomly assigned to either receive methylprednisolone or not for 7 days. The primary end point was the incidence of clinical deterioration 14 days after randomization. RESULTS: We terminated this trial early because the number of patients with COVID-19 pneumonia in all the centers decreased in late March. Finally, a total of 86 COVID-19 patients underwent randomization. There was no difference of the incidence of clinical deterioration between the methylprednisolone group and control group (4.8 vs. 4.8%, p = 1.000). The duration of throat viral RNA detectability in the methylprednisolone group was 11 days (interquartile range, 6-16 days), which was significantly longer than that in the control group (8 days [2-12 days], p = 0.030). There were no significant differences between the 2 groups in other secondary outcomes. Mass cytometry discovered CD3+ T cells, CD8+ T cells, and NK cells in the methylprednisolone group which were significantly lower than those in the control group after randomization (p < 0.05). CONCLUSIONS: From this prematurely closed trial, we found that the short-term early use of corticosteroid could suppress the immune cells, which may prolong severe acute respiratory syndrome coronavirus 2 shedding in patients with COVID-19 pneumonia. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04273321.

Outbreaks of Highly Pathogenic Avian Influenza (H5N6) Virus Subclade 2.3.4.4h in Swans, Xinjiang, Western China, 2020.

In January 2020, the subclade 2.3.4.4h of highly pathogenic avian influenza (H5N6) virus infected migratory whooper swans and mute swans in Xinjiang, western China. The virus is lethal to chickens and ducks but has low pathogenicity in mice. Antigenically, this subclade is similar to the H5N1 vaccine seed virus Re-11.

A20 enhances mu-opioid receptor function by inhibiting beta-arrestin2 recruitment.

Opioids are widely used in clinical practice because of their strong analgesia. However, their use is restricted by such factors as tolerance and opioid-induced hyperalgesia (OIH), so it is critical to find ways to reduce the dosage of opioids to avoid the side effects. In this study, we demonstrated for the first time the regulatory role of A20 in morphine analgesia. By overexpressing and knocking down A20 in the spinal cord of mice, we found that A20 enhanced morphine analgesia rather than tolerance. Then, at the cellular level, different methods were used to confirm that A20 could not only strengthen the inhibition of cAMP induced by opioids drugs, but also affect µ opioid receptor (MOR) and ERK phosphorylation. In addition, we found that A20 interacted with MOR inhibitory protein ß-arrestin2, which could be enhanced by MOR agonists. Furthermore, there was evidence that A20 could inhibit ß-arrestin2 recruitment. Collectively, our results indicated that A20 in the spinal cord could enhance morphine analgesia and increase MOR function through ß-arrestin2. Upregulating A20 expression may be a potential strategy to improve the therapeutic profile of opioids and reduce their side effects.

Effects of Glycosylation and d-Amino Acid Substitution on the Antitumor and Antibacterial Activities of Bee Venom Peptide HYL.

Glycosylation is a promising strategy for modulating the physicochemical properties of peptides. However, the influence of glycosylation on the biological activities of peptides remains unknown. Here, we chose the bee venom peptide HYL as a model peptide and 12 different monosaccharides as model sugars to study the effects of glycosylation site, number, and monosaccharide structure on the biochemical properties, activities, and cellular selectivities of HYL derivatives. Some analogues of HYL showed improvement not only in cell selectivity and proteolytic stability but also in antitumor and antimicrobial activity. Moreover, we found that the helicity of glycopeptides can affect its antitumor activity and proteolytic stability, and the α-linked d-monosaccharides can effectively improve the antitumor activity of HYL. Therefore, it is possible to design peptides with improved properties by varying the number, structure, and position of monosaccharides. What's more, the glycopeptides HYL-31 and HYL-33 show a promising prospect for antitumor and antimicrobial drugs development, respectively. In addition, we found that the d-lysine substitution strategy can significantly improve the proteolytic stability of HYL. Our new approach provides a reference or guidance for the research of novel antitumor and antimicrobial peptide drugs.

MIR205HG acts as a ceRNA to expedite cell proliferation and progression in lung squamous cell carcinoma via targeting miR-299-3p/MAP3K2 axis.

INTRODUCTION: Long noncoding RNAs (lncRNAs) have been associated with many types of cancers, but their molecular mechanisms in lung squamous cell carcinoma (LUSC) have not been fully studied. Therefore, the current study investigated the regulation role of microRNA-205 host gene (MIR205HG) in LUSC and recognized the target genes managed by this lncRNA. METHODS: MIR205HG expression was assessed by the quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The effects of silenced MIR205HG on cell biological behaviors were detected by colony formation assay, transwell assay, flow cytometry analysis and western blot analysis. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay were utilized to proof the binding relationship between miR-299-3p and MIR205HG/mitogen-activated protein kinase kinase kinase 2 (MAP 3 K2). RESULTS: The expression levels of MIR205HG in LUSC tissues and cell lines were obviously up-regulated. Down-regulation of MIR205HG expression remarkably reduced cell proliferation, migration and epithelial-to-mesenchymal transition (EMT) progression, whereas promoted cell apoptosis. MIR205HG could bind with miR-299-3p and down-regulation of MIR205HG elevated miR-299-3p expression. MAP 3 K2 acted as the target gene of miR-299-3p and was up-regulated by MIR205HG overexpression. Overexpressing MAP 3 K2 could counteract the effects of down-regulating MIR205HG on LUSC progression to some degree. CONCLUSION: MIR205HG acts as a competing endogenous RNA (ceRNA) to expedite cell proliferation and progression via targeting miR-299-3p in LUSC.

Total synthesis and cyclization strategy of samoamide A, a cytotoxic cyclic octapeptide rich in proline and phenlalanine isolated from marine cyanobacterium.

Samoamide A is a cyclic octapeptide rich in proline and phenylalanine residues isolated from an American Samoa marine cyanobacterium, which exhibits potent activity against H460 human non-small-cell lung cancer cells (IC50 of 1.1 µM). The first total synthesis of samoamide A was achieved by employing a strategy of a solid-phase peptide synthesis (SPPS) and a head-to-tail cyclization selecting free steric-hinrance connection sites. Then the final product was purified and identified. This strategy not only provides a basis in producing potent cytotoxic agents for drug discovery, but also provides a reference to the total synthesis of proline-rich peptides.

ABIN-1 Negatively Regulates µ-Opioid Receptor Function.

The µ-opioid receptor (MOR) is a Gi/o protein-coupled receptor that mediates analgesic, euphoric, and reward effects. Using a bacterial two-hybrid screen, we reported that the carboxyl tail of the rat MOR associates with A20-binding inhibitor of nuclear factor κB (ABIN-1). This interaction was confirmed by direct protein-protein binding and coimmunoprecipitation of MOR and ABIN-1 proteins in cell lysates. Saturation binding studies showed that ABIN-1 had no effect on MOR binding. However, the interaction of ABIN-1 and MOR inhibited the activation of G proteins induced by DAMGO ([d-Ala2,N-Me-Phe4,Gly5-ol]-Enkephalin). MOR phosphorylation, ubiquitination, and internalization induced by DAMGO were decreased in Chinese hamster ovary cells that coexpressed MOR and ABIN-1. The suppression of forskolin-stimulated adenylyl cyclase by DAMGO was also inhibited by the interaction of ABIN-1 with MOR. In addition, extracellular signal-regulated kinase activation was also negatively regulated by overexpression of ABIN-1. These data suggest that ABIN-1 is a negative coregulator of MOR activation, phosphorylation, and internalization in vitro. ABIN-1 also inhibited morphine-induced hyperlocomotion in zebrafish larvae (AB strain). By utilization of an antisense morpholino oligonucleotide (MO) gene knockdown technology, the ABIN-1 MO-injected zebrafish larvae showed a significant increase (approximately 60%) in distance moved compared with control MO-injected larvae after acute morphine treatment (P < 0.01). Taken together, ABIN-1 negatively regulates MOR function in vitro and in vivo.

The opioid receptor triple agonist DPI-125 produces analgesia with less respiratory depression and reduced abuse liability.

Opioid analgesics remain the first choice for the treatment of moderate to severe pain, but they are also notorious for their respiratory depression and addictive effects. This study focused on the pharmacology of a novel opioid receptor mixed agonist DPI-125 and attempted to elucidate the relationship between the δ-, µ- and κ-receptor potency ratio and respiratory depression and abuse liability. Five diarylmethylpiperazine compounds (DPI-125, DPI-3290, DPI-130, KUST202 and KUST13T02) were selected for this study. PKA fluorescence redistribution assays in CHO cells individually expressing δ-, µ- or κ-receptors were used to measure the agonist potency. The respiratory safety profiles were estimated in rats by the ratio of ED50 (pCO2 increase)/ED50 (antinociception). The abuse liability of DPI-125 was evaluated with a self-administration model in rhesus monkeys. The observed agonist potencies of DPI-125 for δ-, µ- and κ-opioid receptors were 4.29±0.36, 11.10±3.04, and 16.57±4.14 nmol/L, respectively. The other four compounds were also mixed agonists with varying potencies. DPI-125 exhibited a high respiratory safety profile, clearly related to its high δ-receptor potency. The ratio of the EC50 potencies for the µ- and δ-receptors was found to be positively correlated with the respiratory safety ratio. DPI-125 has similar potencies for µ- and κ-receptors, which is likely the reason for its reduced abuse potential. Our results demonstrate that the opioid receptor mixed agonist DPI-125 is safer and less addictive than traditional µ-agonist analgesics. These findings suggest that the development of δ>µâˆ¼κ opioid receptor mixed agonists is feasible, and such compounds could represent a promising class of potent analgesics with wider therapeutic windows.

Gain-of-function mutations in SCN11A cause familial episodic pain.

Many ion channel genes have been associated with human genetic pain disorders. Here we report two large Chinese families with autosomal-dominant episodic pain. We performed a genome-wide linkage scan with microsatellite markers after excluding mutations in three known genes (SCN9A, SCN10A, and TRPA1) that cause similar pain syndrome to our findings, and we mapped the genetic locus to a 7.81 Mb region on chromosome 3p22.3-p21.32. By using whole-exome sequencing followed by conventional Sanger sequencing, we identified two missense mutations in the gene encoding voltage-gated sodium channel Nav1.9 (SCN11A): c.673C>T (p.Arg225Cys) and c.2423C>G (p.Ala808Gly) (one in each family). Each mutation showed a perfect cosegregation with the pain phenotype in the corresponding family, and neither of them was detected in 1,021 normal individuals. Both missense mutations were predicted to change a highly conserved amino acid residue of the human Nav1.9 channel. We expressed the two SCN11A mutants in mouse dorsal root ganglion (DRG) neurons and showed that both mutations enhanced the channel's electrical activities and induced hyperexcitablity of DRG neurons. Taken together, our results suggest that gain-of-function mutations in SCN11A can be causative of an autosomal-dominant episodic pain disorder.

A New Phenothiazine-Based Fluorescent Sensor for Detection of Cyanide.

A new fluorescent sensor for the detection of CN- was developed based on the conjugation of phenothiazine fluorophore and benzofuran unit. By the nucleophilic attacking of CN- to the fluoroacetylamino group in the sensor, the additional reaction of CN- and carbonyl group induced the ICT (intramolecular charge transfer) effect in the molecule and caused the fluorescence quenching sensor. The titration experiments show that the sensor has good sensitivity, selectivity and quick response for CN-. In addition, the fluorescent detection of CN- in the living cell and zebrafish experiments demonstrated the value of the sensor in tracing the CN- in biological systems.

Safety and Efficacy of the Modified Vaccinia Ankara-Bavaria Nordic Vaccine Against Mpox in the Real World: Systematic Review and Meta-Analysis.

In May 2022, mpox began to spread worldwide, posing a serious threat to human public health. Modified Vaccinia Ankara-Bavaria Nordic (MVA-BN) is a live attenuated orthopoxvirus vaccine that has been authorized by the U.S. Food and Drug Administration as the vaccine of choice for the prevention of mpox. In this study, we conducted a meta-analysis of all currently published literature on the efficacy and safety of the MVA-BN vaccine in the real world, showing that the MVA-BN vaccine is effective and safe, with efficacy of up to 75% with a single dose and up to 80% with a two-dose vaccine. Meanwhile, we found that subcutaneous injection has lower local and systemic adverse events than intradermal injection, regardless of single- or two-dose vaccination, and subcutaneous injection is better tolerated in children, the elderly, or people with underlying medical conditions. These results have important reference value for clinical practice.