The highest-elevation frog provides insights into mechanisms and evolution of defenses against high UV radiation.

Defense against ultraviolet (UV) radiation exposure is essential for survival, especially in high-elevation species. Although some specific genes involved in UV response have been reported, the full view of UV defense mechanisms remains largely unexplored. Herein, we used integrated approaches to analyze UV responses in the highest-elevation frog, Nanorana parkeri. We show less damage and more efficient antioxidant activity in skin of this frog than those of its lower-elevation relatives after UV exposure. We also reveal genes related to UV defense and a corresponding temporal expression pattern in N. parkeri. Genomic and metabolomic analysis along with large-scale transcriptomic profiling revealed a time-dependent coordinated defense mechanism in N. parkeri. We also identified several microRNAs that play important regulatory roles, especially in decreasing the expression levels of cell cycle genes. Moreover, multiple defense genes (i.e., TYR for melanogenesis) exhibit positive selection with function-enhancing substitutions. Thus, both expression shifts and gene mutations contribute to UV adaptation in N. parkeri. Our work demonstrates a genetic framework for evolution of UV defense in a natural environment.

Identification and characterization of a novel elastase inhibitor from Hirudinaria manillensis.

A large number of protease inhibitors have been found from leeches, which are essential in various physiological and biological processes. In the curret study, a novel elastase inhibitor was purified and characterized from the leech of Hirudinaria manillensis, which was named HMEI-A. Primary structure analysis showed that HMEI-A belonged to a new family of proteins. HMEI-A exerted inhibitory effects on elastase and showed potent abilities to inhibit elastase with an inhibition constant (Ki) of 1.69 × 10-8 mol·L-1. Further study showed that HMEI-A inhibited the formation of neutrophil extracellular trap (NET). These results suggested that HMEI-A from the leech of H. manillensis is a novel elastase inhibitor which can suppress NET formation. It may play a significant role in blood-sucking of leeches and is a potential candidate as an anti-inflammatory agent.

Dalbavancin binds ACE2 to block its interaction with SARS-CoV-2 spike protein and is effective in inhibiting SARS-CoV-2 infection in animal models.

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a pandemic worldwide. Currently, however, no effective drug or vaccine is available to treat or prevent the resulting coronavirus disease 2019 (COVID-19). Here, we report our discovery of a promising anti-COVID-19 drug candidate, the lipoglycopeptide antibiotic dalbavancin, based on virtual screening of the FDA-approved peptide drug library combined with in vitro and in vivo functional antiviral assays. Our results showed that dalbavancin directly binds to human angiotensin-converting enzyme 2 (ACE2) with high affinity, thereby blocking its interaction with the SARS-CoV-2 spike protein. Furthermore, dalbavancin effectively prevents SARS-CoV-2 replication in Vero E6 cells with an EC50 of ~12 nM. In both mouse and rhesus macaque models, viral replication and histopathological injuries caused by SARS-CoV-2 infection are significantly inhibited by dalbavancin administration. Given its high safety and long plasma half-life (8-10 days) shown in previous clinical trials, our data indicate that dalbavancin is a promising anti-COVID-19 drug candidate.

Seven new veratramine-type alkaloids with potent analgesic effect from Veratrum taliense.

ETHNOPHARMACOLOGICAL RELEVANCE: Veratrum taliense is traditionally used TCMs in Yunnan province of China for pain and inflammation. Previous research and clinical applications have shown that V. taliense had significant analgesic activity. Jevine-type alkaloids were shown to be one of the anti-inflammatory and analgesic agents from V. taliense. However, other types of compounds from V. taliense related to its traditional use remains unknown. AIM OF THE STUDY: To identify veratramine-type steroidal alkaloids with analgesic effects from the roots and rhizomes of V. taliense. MATERIALS AND METHODS: Compounds were isolated from the roots and rhizomes of V. taliense by chromatographic separation. Their structures were elucidated based on UV, IR, NMR and MS spectra data. Analgesic activity was assessed with acetic acid-induced writhing in mice model. RESULTS: Seven new veratramine-type alkaloids were isolated from the roots and rhizomes of V. taliense. They all exhibited significant analgesic activity, of which alkaloids 1 and 4 were more potent antalgic than the well-known analgesic drug, pethidine. CONCLUSIONS: The veratramine-type alkaloids from V. taliense may serve as new leads for the discovery of analgesic drugs.

Purification and characterization of a novel anti-coagulant from the leech Hirudinaria manillensis.

Protease inhibitors have been reported rarely from the leech Hirudinaria manillensis. In this study, we purified a novel protease inhibitor (bdellin-HM-2) with anticoagulant properties from H. manillensis. With a molecular weight of 1.4x104, bdellin-HM-2 was also characterized with three intra-molecular disulfide bridges at the N-terminus and multiple HHXDD and HXDD motifs at the C-terminus. cDNA cloning revealed that the putative nucleotide-encoding protein of bdellin-HM-2 contained 132 amino acids and was encoded by a 399 bp open reading frame (ORF). Sequence alignment showed that bdellin-HM-2 shared similarity with the "non-classical" Kazal-type serine protease inhibitors, but had no inhibitory effect on trypsin, elastase, chymotrypsin, kallikrein, factor XIIa (FXIIa), factor XIa (FXIa), factor Xa (FXa), thrombin, or plasmin. Bdellin-HM-2 showed anticoagulant effects by prolonging the activated partial thromboplastin time (aPTT), indicating a role in enabling H. manillensis to obtain a blood meal from its host. Our results suggest that bdellin-HM-2 may play a crucial role in blood-sucking in this leech species and may be a potential candidate for the development of clinical anti-thrombotic drugs.

Alkaloids from Veratrum taliense Exert Cardiovascular Toxic Effects via Cardiac Sodium Channel Subtype 1.5.

Several species of the genus Veratrum that produce steroid alkaloids are commonly used to treat pain and hypertension in China and Europe. However, Veratrum alkaloids (VAs) induce serious cardiovascular toxicity. In China, Veratrum treatment often leads to many side effects and even causes the death of patients, but the pathophysiological mechanisms under these adverse effects are not clear. Here, two solanidine-type VAs (isorubijervine and rubijervine) isolated from Veratrum taliense exhibited strong cardiovascular toxicity. A pathophysiological study indicated that these VAs blocked sodium channels Na(V)1.3-1.5 and exhibited the strongest ability to inhibit Na(V)1.5, which is specifically expressed in cardiac tissue and plays an essential role in cardiac physiological function. This result reveals that VAs exert their cardiovascular toxicity via the Na(V)1.5 channel. The effects of VAs on Na(V)1.3 and Na(V)1.4 may be related to their analgesic effect and skeletal muscle toxicity, respectively.