The fungal secretory peptide micasin induces itch by activating MRGPRX1/C11/A1 on peripheral neurons.

Pruritus is the leading symptom of dermatophytosis. Microsporium canis is one of the predominant dermatophytes causing dermatophytosis. However, the pruritogenic agents and the related molecular mechanisms of the dermatophyte M. canis remain poorly understood. Here, the secretion of the dermatophyte M. canis was found to dose-dependently evoke itch in mice. The fungal peptide micasin secreted from M. canis was then identified to elicit mouse significant scratching and itching responses. The peptide micasin was further revealed to directly activate mouse dorsal root ganglia (DRG) neurons to mediate the non-histaminergic itch. Knockout and antagonistic experiments demonstrated that MRGPRX1/C11/A1 rather than MRGPRX2/b2 activated by micasin contributed to pruritus. The chimera and mutation of MRGPRX1 showed that three domains (ECL3, TMH3 and TMH6) and four hydrophobic residues (Y99, F237, L240 and W241) of MRGPRX1 played the key role in micasin-triggered MRGPRX1 activation. Our study sheds light on the dermatophytosis-associated pruritus and may provide potential therapeutic targets and strategies against pruritus caused by dermatophytes.

Similar neurotoxin expression profiles of traditional Chinese scorpion medicine material between juvenile and adult Mesobuthus martensii scorpions revealed by multiple strategic proteomics.

ETHNOPHARMACOLOGICAL RELEVANCE: The Mesobuthus martensii scorpions, called as "Quanxie", are known Chinese medicinal material base on the "Combat poison with poison" strategy for more than one thousand years, and still widely used to treat various diseases according to the Pharmacopoeia of the People's Republic of China nowadays. AIM OF STUDY: The study aims to investigate the similarity of scorpion neurotoxins at the protein level between the juvenile and adult Mesobuthus martensii scorpions as Chinese medicine materials. MATERIALS AND METHODS: The second-, third- and fourth-instar, and adult Mesobuthus martensii scorpions were collected for the characterization of neurotoxin expression through multiple strategic proteomics, including undigested scorpion venom, endopeptidase-digested, and undigested scorpion telson extract for the sample analysis. RESULTS: Based on the known 107 scorpion neurotoxins from the genomic and transcriptomic analysis of adult Mesobuthus martensii scorpions, the multiple strategic proteomics first revealed that neurotoxins exhibited more stability in telson extract than secreted venom. In the reported transcripts of scorpion neurotoxins, approximately 53%, 56%, 66% and 78% of neurotoxins were detected through undigested scorpion venom, the endopeptidase Arg-C-, Lys-C-digested telson extract, and undigested telson extract strategies, respectively. Nearly 79% of scorpion neurotoxins detected in third-instar Mesobuthus martensii scorpions represent the largest number of scorpion neurotoxins from proteomic analysis to date. Moreover, a total of 84% of scorpion neurotoxins were successfully identified at the protein level, and similar neurotoxin expression profiles in second-, third- and fourth-instar, and adult Mesobuthus martensii scorpions were first revealed by the multiple strategic proteomics. CONCLUSION: These findings for the first time demonstrate the similar neurotoxin expression profiles between the juvenile and adult Mesobuthus martensii scorpions as Chinese medicinal material, which would serve as a paradigm for further toxin analysis from different venomous animals.

The Tick Saliva Peptide HIDfsin2 TLR4-Dependently Inhibits the Tick-Borne Severe Fever with Thrombocytopenia Syndrome Virus in Mouse Macrophages.

Ticks transmit a variety of pathogens to their hosts by feeding on blood. The interactions and struggle between tick pathogens and hosts have evolved bilaterally. The components of tick saliva can directly or indirectly trigger host biological responses in a manner that promotes pathogen transmission; however, host cells continuously develop strategies to combat pathogen infection and transmission. Moreover, it is still unknown how host cells develop their defense strategies against tick-borne viruses during tick sucking. Here, we found that the tick saliva peptide HIDfsin2 enhanced the antiviral innate immunity of mouse macrophages by activating the Toll-like receptor 4 (TLR4) signaling pathway, thereby restricting tick-borne severe fever with thrombocytopenia syndrome virus (SFTSV) replication. HIDfsin2 was identified to interact with lipopolysaccharide (LPS), a ligand of TLR4, and then depolymerize LPS micelles into smaller particles, effectively enhancing the activation of the nuclear factor kappa-B (NF-κB) and type I interferon (IFN-I) signaling pathways, which are downstream of TLR4. Expectedly, TLR4 knockout completely eliminated the promotion effect of HIDfsin2 on NF-κB and type I interferon activation. Moreover, HIDfsin2 enhanced SFTSV replication in TLR4-knockout mouse macrophages, which is consistent with our recent report that HIDfsin2 hijacked p38 mitogen-activated protein kinase (MAPK) to promote the replication of tick-borne SFTSV in A549 and Huh7 cells (human cell lines) with low expression of TLR4. Together, these results provide new insights into the innate immune mechanism of host cells following tick bites. Our study also shows a rare molecular event relating to the mutual antagonism between tick-borne SFTSV and host cells mediated by the tick saliva peptide HIDfsin2 at the tick-host-virus interface.

Differential fluorescence features and recovery speeds of different scorpion exoskeleton parts during the molting process.

Scorpion fluorescence under ultraviolet light is a well-known phenomenon, but its features under excitation in the UVA, UVB and UVC bands have not been characterized. Systematic fluorescence characterization revealed indistinguishable fluorescence spectra with a peak wavelength of 475 nm for whole exuviae from second-, third- and fifth-instar scorpions under different ultraviolet light ranges. In-depth investigations of the chelae, mesosoma, metasoma and telson of adult scorpions further indicated heterogeneity in the typical fluorescence spectrum within the visible light range and in the newly reported fluorescence spectrum with a peak wavelength of 320 nm within the ultraviolet light range, which both showed excitation wavelength-independent features. Dynamic fluorescence changes during the molting process of third-instar scorpions revealed the fluorescence heterogeneity-dependent recovery speed of scorpion exoskeletons. The typical fluorescence spectra of the molted chelae and telson rapidly recovered approximately 6 h after ecdysis under UVA light and approximately 36 h after ecdysis under UVB and UVC light. However, it took approximately 12 h and 24 h to obtain the typical fluorescence spectra of the molted metasoma and mesosoma, respectively, under UVA irradiation and 72 h to obtain the typical fluorescence spectra under UVB and UVC irradiation. The fluorescence heterogeneity-dependent fluorescence recovery of the scorpion exoskeleton was further confirmed by tissue section analysis of different segments from molting third-instar scorpions. These findings reveal novel scorpion fluorescence features and provide potential clues on the biological function of scorpion fluorescence.

CD74-ROS1 L2026M mutant enhances autophagy through the MEK/ERK pathway to promote invasion, metastasis and crizotinib resistance in non-small cell lung cancer cells.

The treatment of non-small cell lung cancer (NSCLC) patients harboring a proto-oncogene tyrosine-protein kinase c-ros oncogene 1 (ROS1) fusion gene has greatly benefited from the use of crizotinib. However, drug resistance inevitably occurs after 1 year of treatment. Clinical studies have shown that patients with an L2026M mutation in the ROS1 kinase domain account for about 6% of the total number of crizotinib-resistant cases, which is an important group that cannot be ignored. To explore the mechanism involved, we constructed the HLA class II histocompatibility antigen gamma chain (CD74)-ROS1 L2026M mutant gene by fusion polymerase chain reaction (PCR) and transfected it into H460 and A549 cells. We found that the invasion and metastasis abilities of drug-resistant cells were increased. The results of monodansylcadaverine (MDC) staining, Acridine orange (AO) staining, and western blot indicated that the autophagy level of CD74-ROS1 L2026M mutant NSCLC cells was increased compared with the CD74-ROS1 group, and the inhibition of autophagy could reverse the increased invasion and metastasis abilities caused by the L2026M mutation. In addition, the L2026M mutation led to excessive activation of the MEK/ERK pathway, and MEK inhibitors could reduce the autophagy level, invasion, and metastasis abilities of cells; additionally, this process could be blocked by rapamycin, an activator of autophagy. Furthermore, crizotinib treatment activated expression of Src homology region 2 domain-containing phosphatase-2 (SHP2; also known as PTPN11) to upregulate the MEK/ERK pathway, and the combination of MEK inhibitors and crizotinib increased apoptosis compared with crizotinib alone. In conclusion, our results indicate that the MEK/ERK pathway mediates the induction of invasion, metastasis, and crizotinib resistance through autophagy caused by CD74-ROS1 L2026M mutation in NSCLC cells, and targeting MEK could reverse these processes.

Scorpion venom peptides: Molecular diversity, structural characteristics, and therapeutic use from channelopathies to viral infections and cancers.

Animal venom is an important evolutionary innovation in nature. As one of the most representative animal venoms, scorpion venom contains an extremely diverse set of bioactive peptides. Scorpion venom peptides not only are 'poisons' that immobilize, paralyze, kill, or dissolve preys but also become important candidates for drug development and design. Here, the review focuses on the molecular diversity of scorpion venom peptides, their typical structural characteristics, and their multiple therapeutic or pharmaceutical applications in channelopathies, viral infections and cancers. Especially, the group of scorpion toxin TRPTx targeting transient receptor potential (TRP) channels is systematically summarized and worthy of attention because TRP channels play a crucial role in the regulation of homeostasis and the occurrence of diseases in human. We also further establish the potential relationship between the molecular characteristics and functional applications of scorpion venom peptides to provide a research basis for modern drug development and clinical utilization of scorpion venom resources.

Functional Characterization of a New Degradation Peptide BmTX4-P1 from Traditional Chinese Scorpion Medicinal Material.

Thermally processed Buthus martensii Karsch scorpion is an important traditional Chinese medical material that has been widely used to treat various diseases in China for over one thousand years. Our recent work showed that thermally processed Buthus martensii Karsch scorpions contain many degraded peptides; however, the pharmacological activities of these peptides remain to be studied. Here, a new degraded peptide, BmTX4-P1, was identified from processed Buthus martensii Karsch scorpions. Compared with the venom-derived wild-type toxin peptide BmTX4, BmTX4-P1 missed some amino acids at the N-terminal and C-terminal regions, while containing six conserved cysteine residues, which could be used to form disulfide bond-stabilized α-helical and ß-sheet motifs. Two methods (chemical synthesis and recombinant expression) were used to obtain the BmTX4-P1 peptide, named sBmTX4-P1 and rBmTX4-P1. Electrophysiological experimental results showed that sBmTX4-P1 and rBmTX4-P1 exhibited similar activities to inhibit the currents of hKv1.2 and hKv1.3 channels. In addition, the experimental electrophysiological results of recombinant mutant peptides of BmTX4-P1 indicated that the two residues of BmTX4-P1 (Lys22 and Tyr31) were the key residues for its potassium channel inhibitory activity. In addition to identifying a new degraded peptide, BmTX4-P1, from traditional Chinese scorpion medicinal material with high inhibitory activities against the hKv1.2 and hKv1.3 channels, this study also provided a useful method to obtain the detailed degraded peptides from processed Buthus martensii Karsch scorpions. Thus, the study laid a solid foundation for further research on the medicinal function of these degraded peptides.

The tick saliva peptide HIDfsin2 promotes the tick-borne virus SFTSV replication in vitro by enhancing p38 signal pathway.

Pathogens co-evolved with ticks to facilitate blood collection and pathogen transmission. Although tick saliva was recently found to be rich in bioactive peptides, it is still elusive which saliva peptide promotes virus transmission and which pathways are invovled. Here, we used a saliva peptide HIDfsin2 and a severe fever with thrombocytopenia syndrome virus (SFTSV) both carried by the tick Haemaphysalis longicornis to elucidate the relationship between tick saliva components and tick-borne viruses. HIDfsin2 was found to promote the replication of SFTSV in a dose-dependent manner in vitro. HIDfsin2 was further revealed to MKK3/6-dependently magnify the activation of p38 MAPK. The overexpression, knockdown and phosphorylation site mutation of p38α indicated that p38 MAPK activation facilitated SFTSV infection in A549 cells. Moreover, the blockade of p38 MAPK activation significantly suppressed SFTSV replication. Differently, HIDfsin2 or pharmacological inhibition of p38 MAPK activation had no effect on a mosquito-borne Zika virus (ZIKV). All these results showed that HIDfsin2 specifically promoted SFTSV replication through the MKK3/6-dependent enhancement of p38 MAPK activation. Our study provides a new perspective on the transmission of tick-borne viruses under natural conditions, and supports that the blockade of p38 MAPK activation can be a promising strategy against the mortal tick-borne virus SFTSV.

Targeting HMGA1 contributes to immunotherapy in aggressive breast cancer while suppressing EMT.

Metastasis is an obstacle to the clinical treatment of aggressive breast cancer (BC). Studies have shown that high mobility group A1 (HMGA1) is abnormally expressed in various cancers and mediates tumor proliferation and metastasis. Here, we provided more evidence that HMGA1 mediated epithelial to mesenchymal transition (EMT) through the Wnt/ß-catenin pathway in aggressive BC. More importantly, HMGA1 knockdown enhanced antitumor immunity and improved the response to immune checkpoint blockade (ICB) therapy by upregulating programmed cell death ligand 1 (PD-L1) expression. Simultaneously, we revealed a novel mechanism by which HMGA1 and PD-L1 were regulated by the PD-L1/HMGA1/Wnt/ß-catenin negative feedback loop in aggressive BC. Taken together, we believe that HMGA1 can serve as a target for the dual role of anti-metastasis and enhancing immunotherapeutic responses.

A Pseudomonas Lysogenic Bacteriophage Crossing the Antarctic and Arctic, Representing a New Genus of Autographiviridae.

Polar regions tend to support simple food webs, which are vulnerable to phage-induced gene transfer or microbial death. To further investigate phage-host interactions in polar regions and the potential linkage of phage communities between the two poles, we induced the release of a lysogenic phage, vB_PaeM-G11, from Pseudomonas sp. D3 isolated from the Antarctic, which formed clear phage plaques on the lawn of Pseudomonas sp. G11 isolated from the Arctic. From permafrost metagenomic data of the Arctic tundra, we found the genome with high-similarity to that of vB_PaeM-G11, demonstrating that vB_PaeM-G11 may have a distribution in both the Antarctic and Arctic. Phylogenetic analysis indicated that vB_PaeM-G11 is homologous to five uncultured viruses, and that they may represent a new genus in the Autographiviridae family, named Fildesvirus here. vB_PaeM-G11 was stable in a temperature range (4-40 °C) and pH (4-11), with latent and rise periods of about 40 and 10 min, respectively. This study is the first isolation and characterization study of a Pseudomonas phage distributed in both the Antarctic and Arctic, identifying its lysogenic host and lysis host, and thus provides essential information for further understanding the interaction between polar phages and their hosts and the ecological functions of phages in polar regions.

Design, synthesis and antitumor activity of novel thiophene- triazine derivatives bearing arylurea unit as potent PI3K/mTOR inhibitorss.

In this article, we designed and synthesized a series of novel thiophene-triazine derivatives bearing arylurea unit as potent dual PI3K/mTOR inhibitors. The cytotoxicity of all the target compounds were evaluated against nine cancer cell lines (breast cancer cell line MCF-7, lung cancer cell lines A549, NCI-H460, H2228 and H1975, cervical cancer cell lines Hela and Hela-MDR, ovarian cancer cell lines Ovcar-2 and glioma U87MG) and the kinase inhibitory activity against PI3K/mTOR kinases was also tested. The results demonstrated that most of the target compounds exhibited moderate to excellent activity and high selectivity against one or more cancer cell lines. Among them, seven compounds displayed better activity than lead compound GDC-0941. The inhibitory activity of the most promising compound on nine cancer cell lines was 302.5 times better than that of GDC-0941 with the IC50 values as low as 0.008 ± 0.002 µM, and the inhibitory activity against PI3Kα and mTOR kinase was excellent, with the IC50 values of 177.41 and 12.24 nM, respectively, indicating that it was a potential dual PI3Kα/mTOR inhibitor. The Structure-Activity Relationships (SARs) indicated that the introduction of the arylurea group significantly improved the cellular and kinase activities of the target compounds. Moreover, the results of toxicity and hemolysis experiments demonstrated that the most promising compound had low toxicity and good safety. The results of PCR assay and molecular docking modes showed that it was a potential PI3K/mTOR inhibitor, which was worthy of further study.

Key domains and residues of the receptor MRGPRX1 recognizing the peptide ligand BAM8-22.

Mas-related G protein-coupled receptors (Mrgprs) are a newly discovered class of G protein-coupled receptors consisting of more than 50 members in recent years. MRGPRX1 can be activated by bovine adrenal medulla peptide 8-22 (BAM8-22), triggering Ca2+ influx and then causing pain and itch. It is very important for the discovery of analgesic and antipruritic drugs to elucidate the molecular mechanism of MRGPRX1 recognizing BAM8-22. Here, we identified the functional domains and residues of the receptor MRGPRX1 activating BAM8-22 through molecular model, mutation and living cell calcium imaging. The molecular docking predicted that BAM8-22 interacted with N-terminal, TM4, TM5, TM6 and ECL3 of MRGPRX1. Both ECL3 and TM6 domains were further revealed to play a critical role in the BAM8-22-induced MRGPRX1 activation, whereas TM3 region performed a secondary function. Moreover, the mutation F237A of MRGPRX1 completely lost the activation ability of BAM8-22. These results were consistent with the cryogenic electron microscopy (cryo-EM) structure of MRGPRX1-Gαq in complex with BAM8-22 reported most recently. Taken together, our work shows insights into the molecular mechanism of the interaction between the receptor MRGPRX1 and the peptide agonist BAM8-22, and will also provide some valuable clues for the design of analgesic and antipruritic drugs targeting MRGPRX1.

Proteomic Analysis of Exudates from Chronic Ulcer of Diabetic Foot Treated with Scorpion Antimicrobial Peptide.

Scorpion peptides have good therapeutic effect on chronic ulcer of diabetic foot, but the related pharmacological mechanism has remained unclear. The different proteins and bacteria present in ulcer exudates from chronic diabetic foot patients, treated with scorpion antimicrobial peptide at different stages, were analyzed using isobaric tags for quantification-labeled proteomics and bacteriological methods. According to the mass spectrometry data, a total of 1865 proteins were identified qualitatively, and the number of the different proteins was 130 (mid/early), 401 (late/early), and 310 (mid, late/early). In addition, functional annotation, cluster analysis of effects and the analysis of signal pathway, transcription regulation, and protein-protein interaction network were carried out. The results showed that the biochemical changes of wound microenvironment during the treatment involved activated biological functions such as protein synthesis, cell proliferation, differentiation, migration, movement, and survival. Inhibited biological functions such as cell death, inflammatory response, immune diseases, and bacterial growth were also involved. Bacteriological analysis showed that Burkholderia cepacia was the main bacteria in the early and middle stage of ulcer exudate and Staphylococcus epidermidis in the late stage. This study provides basic data for further elucidation of the molecular mechanism of diabetic foot.

XS-2, a novel potent dual PI3K/mTOR inhibitor, exhibits high in vitro and in vivo anti-breast cancer activity and low toxicity with the potential to inhibit the invasion and migration of triple-negative breast cancer.

Breast cancer has become the most commonly diagnosed cancer, surpassing lung cancer, with 2.26 million new breast cancers worldwide in 2020. Hence, there is an urgent need to develop effective molecularly targeted therapeutic drugs to treat breast cancer. In this paper, we designed, synthesized and screened a novel thiophene-triazine derivative, XS-2, as a potent dual PI3K/mTOR inhibitor for the treatment of breast cancer. Also, XS-2 was found to be potentially effective against triple-negative breast cancer (TNBC) in vitro during the investigation. We evaluated the in vitro inhibitory effect of XS-2 on 10 cancer cell lines by MTT and 6 kinases to investigated its in vivo antitumor activity in MCF-7 xenograft tumor-bearing BALB/c nude mice. In addition, the in vitro/in vivo toxicity to mice was also assessed by hemolytic toxicity, H&E staining and blood biochemical analysis. In order to investigate the antitumor mechanism of XS-2, a series of experiments were carried out in vitro/in vivo animal model and molecular biological levels such as the cell cycle and the apoptosis assay, real-time PCR, western blot, docking and molecular simulations analysis, etc. What's more, wound healing assay, Transwell and Western Blot were applied to explore the ability of XS-2 to inhibit the cell invasion and migration. The results showed that XS-2 exhibited strong antitumor activity both in vitro and in vivo. The inhibitory activities of XS-2 on ten cancer cell lines were ranging from 1.07 ± 0.11 to 0.002 ± 0.001 µM, which were 1565 times better than that of the lead compound GDC-0941, inhibitory activities against PI3Kα and mTOR kinases were 291.0 and 60.8 nM, respectively. Notably, XS-2 not only showed significant in vivo antitumor activity and low toxicity, with the tumor inhibition rate of 57.0 %, but also exhibited strong inhibitory in the expression of related proteins of PI3K pathway in tumor tissues. In addition, XS-2 significantly inhibited breast cancer MCF-7 and MDA-MB-231 cells in a concentration- and time-dependent manner, and inhibited the migration and invasion ability of MDA-MB-231 and MCF-7 cells. More than that, XS-2 could inhibit the increase of the expression levels of N-cadherin and vimentin upregulated by EGF and reversed the E-cadherin expression down regulated by EGF, resulting in inhibiting EMT in MCF-7 and MDA-MB-231 cells. The results showed that XS-2 was expected to be successfully developed as a high-efficiency and low-toxicity breast cancer therapeutic drug with the potential to inhibit the invasion and migration of TNBC. This provides a new research idea for the treatment of TNBC, which is of great significance.

SARS-CoV-2, COVID-19, and Reproduction: Effects on Fertility, Pregnancy, and Neonatal Life.

Since its discovery in Wuhan, China, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread over the world, having a huge impact on people's lives and health. The respiratory system is often targeted in people with the coronavirus disease 2019 (COVID-19). The virus can also infect many organs and tissues in the body, including the reproductive system. The consequences of the SARS-CoV-2 infection on fertility and pregnancy in hosts are poorly documented. Available data on other coronaviruses, such as severe acute respiratory syndrome (SARS-CoV) and Middle Eastern Respiratory Syndrome (MERS-CoV) coronaviruses, identified pregnant women as a vulnerable group with increased pregnancy-related complications. COVID-19 was also shown to impact pregnancy, which can be seen in either the mother or the fetus. Pregnant women more likely require COVID-19 intensive care treatment than non-pregnant women, and they are susceptible to giving birth prematurely and having their newborns admitted to the neonatal intensive care unit. Angiotensin converting enzyme 2 (ACE2), a key player of the ubiquitous renin-angiotensin system (RAS), is the principal host cellular receptor for SARS-CoV-2 spike protein. ACE2 is involved in the regulation of both male and female reproductive systems, suggesting that SARS-CoV-2 infection and associated RAS dysfunction could affect reproduction. Herein, we review the current knowledge about COVID-19 consequences on male and female fertility, pregnant women, and their fetuses. Furthermore, we describe the effects of COVID-19 vaccination on reproduction.