Inhibition of protein synthesis by the cordycepin analog of (2'-5')ppp(Ap)nA, (2'-5')ppp(3'dAp)n3'dA, in intact mammalian cells

The introduction of the cordycepin analog of (2'-5')An, (2'-5')ppp(3'dAp)n3'dA [referred to as (2'-5')p33'dAn], into mouse L929 cells and cultured human fibroblasts resulted in a dose-dependent inhibition of protein synthesis which was comparable to the inhibition observed by (2'-5')ppp(Ap)nA [referred to as (2'-5')p3An]. The inhibition of protein synthesis by (2'-5')p33'dAn was much more persistent than that of the naturally occurring (2'-5')p3An following prolonged incubation of cells. Furthermore, the (2'-5')p3An was cytotoxic to mammalian cells in culture, whereas the (2'-5')p33'dAn was not.     

Cordycepin activates AMP‐activated protein kinase (AMPK) via interaction with the γ1 subunit

Cordycepin is a bioactive component of the fungus Cordyceps militaris. Previously, we showed that cordycepin can alleviate hyperlipidemia through enhancing the phosphorylation of AMP‐activated protein kinase (AMPK), but the mechanism of this stimulation is unknown. Here, we investigated the potential mechanisms of cordycepin‐induced AMPK activation in HepG2 cells. Treatment with cordycepin largely reduced oleic acid (OA)‐elicited intracellular lipid accumulation and increased AMPK activity in a dose‐dependent manner. Cordycepin‐induced AMPK activation was not accompanied by changes in either the intracellular levels of AMP or the AMP/ATP ratio, nor was it influenced by calmodulin‐dependent protein kinase kinase (CaMKK) inhibition; however, this activation was significantly suppressed by liver kinase B1 (LKB1) knockdown. Molecular docking, fluorescent and circular dichroism measurements showed that cordycepin interacted with the γ1 subunit of AMPK. Knockdown of AMPKγ1 by siRNA substantially abolished the effects of cordycepin on AMPK activation and lipid regulation. The modulating effects of cordycepin on the mRNA levels of key lipid regulatory genes were also largely reversed when AMPKγ1 expression was inhibited. Together, these data suggest that cordycepin may inhibit intracellular lipid accumulation through activation of AMPK via interaction with the γ1 subunit.     

Efficient production of cordycepin by the Cordyceps militaris mutant G81-3 for practical use

Cordycepin is one of the most versatile metabolites of Cordyceps militaris. When C. militaris G81-3, the mutant obtained by a proton beam irradiation, was cultivated by liquid surface culture, cordycepin was found to crystallize in the medium due to high cordycepin concentration. Because the cordycepin crystals strongly attached to the mycelial mat, complete recovery of cordycepin was difficult. To prevent cordycepin crystallization, increase of the initial medium volume was examined to decrease the condensation rate by vaporization, in combination with decrease of the initial substrate level. Besides, addition of the water to the culture bottle was examined to cancel out the medium condensation. A 7.4 g/L of cordycepin was obtained without crystallization by the former method. The upper limit of cordycepin production, 14.3 g/L, was obtained by the latter method and this value was the highest level of all the previous reports. A 2.5-fold scale-up of the culture slightly declined the production rate, however, the amount of cordycepin production was properly 2.5 times higher than that of the small scale. In addition, differences in sensitivities to the substrates between the mutant and the wild-type strain are discussed.     

Cordycepin: A bioactive metabolite with therapeutic potential

Cytotoxic nucleoside analogues were the first chemotherapeutic agents for cancer treatment. Cordycepin, an active ingredient of the insect fungus Cordyceps militaris, is a category of compounds that exhibit significant therapeutic potential. Cordycepin has many intracellular targets, including nucleic acid (DNA/RNA), apoptosis and cell cycle, etc. Investigations of the mechanism of anti-cancer drugs have yielded important information for the design of novel drug targets in order to enhance anti-tumor activity with less toxicity to patients. This extensive review covers various molecular aspects of cordycepin interactions with its recognized cellular targets and proposes the development of novel therapeutic strategies for cancer treatment.     

Adenosine kinase-deficient mutant of Saccharomyces cerevisiae

Abstract A cordycepin-resistant mutant strain of Saccharomyces cerevisiae (CD-R2) was found to be deficient in adenosine kinase. This mutant accumulated S-adenosylhomocysteine during growth in the presence of exogenous adenosine and it grew in a pseudohyphal manner in the presence of this nucleotide.     

蛹虫草表型多态性对子实体产生及虫草菌素的影响

为选育高产子实体和虫草菌素的蛹虫草菌株,从野生蛹虫草中分离单孢子并进行分型,之后进行产子实体实验;同时对蛹虫草子实体进行了产孢结构的观察,并用高效液相色谱仪检测了子实体和培养基中的虫草菌素。结果表明,菌落背面颜色为橙铬色的菌株容易产生子实体;出发(原代)菌株所产子实体在形态上更接近野生蛹虫草,而角变株的子实体畸形;出发菌株产子实体能力要比该菌株未发生角变部分分离株和角变部分分离株都强。在虫草菌素的产量上也以出发菌株为高,表明表型多态性对蛹虫草产子实体和虫草菌素有很大的影响。这对于优势菌种的筛选和生产实践有借鉴意义。     

Influence of treatment with 3′-deoxyadenosine associated deoxycoformycin on hematological parameters and activity of adenosine deaminase in infected mice with Trypanosoma evansi

This study aimed to verify the effect of 3′-deoxyadenosine and deoxycoformycin on hematologic parameters and adenosine deaminase (ADA) activity in plasma and brain of mice infected with Trypanosoma evansi. Seventy animals were divided into seven groups, which were divided into two subgroups each for sampling on days 4 and 8 post-infection (PI). The groups were composed of three uninfected groups (A–C), namely, not-treated (A), treated with 3′-deoxyadenosine (B), and treated with deoxycoformycin (C) and four infected groups, mice with T. evansi (D–G), namely, not-treated (D), treated with 3′-deoxyadenosine (E), treated with deoxycoformycin (F), and treated with a combination 3′-deoxyadenosine and deoxycoformycin (G). Hematological parameters and ADA activity were evaluated in plasma and brain. Animals in groups B and C exhibited a reduction in the levels of plasma total protein compared group A. Animals in groups D and F showed changes in the hematological parameters. The ADA activity significantly reduced in the animals of groups C, D, F and G. Mice in the group E presented increased ADA activity in plasma. Therefore, we conclude that the treatment interferes significantly in the hematologic parameters in mice infected with T. evansi. On the other hand, when the ADA inhibitor was used we observed a significant decrease in the values of hematocrit, total erythrocytes, and hemoglobin concentration. The deoxycoformycin was able to inhibit the ADA activity of parasite thus it may be one of the mechanisms of efficacy of this treatment.     

COVID-19 receptor and malignant cancers: Association of CTSL expression with susceptibility to SARS-CoV-2

CTSL is expressed by cancerous tissues and encodes a lysosomal cysteine proteinase that regulates cancer progression and SARS-CoV-2 entry. Therefore, it is critical to predict the susceptibility of cancer patients for SARS-CoV-2 and evaluate the correlation between disease outcomes and the expression of CTSL in malignant cancer tissues. In the current study, we analyzed CTSL expression, mutation rate, survival and COVID-19 disease outcomes in cancer and normal tissues, using online databases. We also performed immunohistochemistry (IHC) to test CTSL expression and western blot to monitor its regulation by cordycepin (CD), and N6, N6-dimethyladenosine (m⁶₂A), respectively. We found that CTSL is conserved across different species, and highly expressed in both normal and cancer tissues from human, as compared to ACE2 or other proteinases/proteases. Additionally, the expression of CTSL protein was the highest in the lung tissue. We show that the mRNA expression of CTSL is 66.4-fold higher in normal lungs and 54.8-fold higher in cancer tissues, as compared to ACE2 mRNA expression in the respective tissues. Compared to other proteases/proteinases/convertases such as TMPRSS2 and FURIN, the expression of CTSL was higher in both normal lungs and lung cancer samples. All these data indicate that CTSL might play an important role in COVID-19 pathogenesis in normal and cancer tissues of the lungs. Additionally, the CTSL-002 isoform containing both the inhibitor_I29 and Peptidase_C1 domains was highly prevalent in all cancers, suggesting its potential role in tumor progression and SARS-CoV-2 entry in multiple types of cancers. Further analysis of the expression of CTSL mutant showed a correlation with FURIN and TMPRSS2, suggesting a potential role of CTSL mutations in modulating SARS-CoV-2 entry in cancers. Moreover, high expression of CTSL significantly correlated with a short overall survival (OS) in lung cancer and glioma. Thus, CTSL might play a major role in the susceptibility of lung cancer and glioma patients to SARS-CoV-2 uptake and COVID-19 severity. Furthermore, CD or m⁶₂A inhibited CTSL expression in the cancer cell lines A549, MDA-MB-231, and/or PC3 in a dose dependent manner. In conclusion, we show that CTSL is highly expressed in normal tissues and increased in most cancers, and CD or m⁶₂A could inhibit its expression, suggesting the therapeutic potential of targeting CTSL for cancer and COVID-19 treatment.     

Anti-HCV activity of the Chinese medicinal fungus Cordyceps militaris

Persistent hepatitis C virus (HCV) infection causes chronic liver diseases and is a global health problem. Although the sustained virologic response rate in the treatment of genotype 1 using new triple therapy (pegylated-interferon, ribavirin, and telaprevir/boceprevir) has been improved by more than 70%, several severe side effects such as skin rash/ageusia and advanced anemia have become a problem. Under these circumstances, a new type of anti-HCV oral drug with few side effects is needed. Our recently developed HCV drug assay systems, including the HuH-7 cell line-derived OR6 and AH1R, and the Li23 cell line-derived ORL8 and ORL11, allow genome-length HCV RNAs (several strains of genotype 1b) encoding renilla luciferase to replicate efficiently. Using these systems as anti-HCV candidates, we have identified numerous existing medicines that can be used against HCV with few side effects, such as statins and teprenon. To obtain additional anti-HCV candidates, we evaluated a number of oral health supplements, and found that the capsule but not the liquid form of Cordyceps militaris (CM) (Ascomycotinanorth, North Chinese caterpillar fungus), which is used as a Chinese herbal medicine, exhibited moderate anti-HCV activity. In combination with interferon-α or ribavirin, CM exhibited an additive inhibitory effect. Among the main components of CM, cordycepin, but not ergosterol, contributed to the anti-HCV activity of CM. In consideration of all these results, we suggest that CM would be useful as an oral anti-HCV agent in combination with interferon-α and/or ribavirin.