Aconitine inhibits androgen synthesis enzymes by rat immature Leydig cells via down-regulating androgen synthetic enzyme expression in vitro

Aconitine and its derivatives: bioactivities, structure-activity relationships and preliminary molecular mechanisms

Aconitine (AC), which is the primary bioactive diterpene alkaloid derived from Aconitum L plants, have attracted considerable interest due to its unique structural feature. Additionally, AC demonstrates a range of biological activities, such as its ability to enhance cardiac function, inhibit tumor growth, reduce inflammation, and provide analgesic effects. However, the structure-activity relationships of AC are remain unclear. A clear understanding of these relationships is indeed critical in developing effective biomedical applications with AC. In line with these challenges, this paper summarized the structural characteristics of AC and relevant functional and bioactive properties and the structure-activity relationships presented in biomedical applications. The primary temporal scope of this review was established as the period spanning from 2010 to 2023. Subsequently, the objective of this review was to provide a comprehensive understanding of the specific action mechanism of AC, while also exploring potential novel applications of AC derivatives in the biomedical field, drawing upon their structural characteristics. In conclusion, this review has provided a comprehensive analysis of the challenges and prospects associated with AC in the elucidation of structure-bioactivity relationships. Furthermore, the importance of exploring modern biotechnology approaches to enhance the potential biomedical applications of AC has been emphasized.

Differential tissue expression of sex steroid-synthesizing enzyme CYP11A1 in male Tibetan sheep (Ovis aries)

Steroid metabolism is a fundament to testicular development and function. The cytochrome P450, family 11, subfamily A, polypeptide 1 (CYP11A1) is a key rate-limiting enzyme for catalyzing the conversion of cholesterol to pregnenolone. However, despite its importance, what expression and roles of CYP11A1 possesses and how it regulates the testicular development and spermatogenesis in Tibetan sheep remains largely unknown. Based on this, we evaluated the expression and localization patterns of CYP11A1 in testes and epididymides of Tibetan sheep at three developmental stages (three-month-old, pre-puberty; one-year-old, sexual maturity and three-year-old, adult) by quantitative real-time PCR (qPCR), western blot and immunofluorescence. The results showed that CYP11A1 mRNA and protein were expressed in testes and epididymides throughout the development stages and obviously more intense in one- and three-year-old groups than three-month-old group (except for the caput epididymidis). Immunofluorescence assay showed that the CYP11A1 protein was mainly located in Leydig cells and epididymal epithelial cells. In addition, positive signals of CYP11A1 protein were observed in germ cells, epididymal connective tissue and sperms stored in the epididymal lumen. Collectively, these results suggested that the CYP11A1 gene might be mainly involved in regulating spermatogenesis and androgen synthesis in developmental Tibetan sheep testis and epididymis.

The potential role of plant secondary metabolites on antifungal and immunomodulatory effect

With the widespread use of antibiotic drugs worldwide and the global increase in the number of immunodeficient patients, fungal infections have become a serious threat to global public health security. Moreover, the evolution of fungal resistance to existing antifungal drugs is on the rise. To address these issues, the development of new antifungal drugs or fungal inhibitors needs to be targeted urgently. Plant secondary metabolites are characterized by a wide variety of chemical structures, low price, high availability, high antimicrobial activity, and few side effects. Therefore, plant secondary metabolites may be important resources for the identification and development of novel antifungal drugs. However, there are few studies to summarize those contents. In this review, the antifungal modes of action of plant secondary metabolites toward different types of fungi and fungal infections are covered, as well as highlighting immunomodulatory effects on the human body. This review of the literature should lay the foundation for research into new antifungal drugs and the discovery of new targets. KEY POINTS: • Immunocompromised patients who are infected the drug-resistant fungi are increasing. • Plant secondary metabolites toward various fungal targets are covered. • Plant secondary metabolites with immunomodulatory effect are verified in vivo.

Antitumor effects and potential mechanisms of aconitine based on preclinical studies: an updated systematic review and meta-analysis

Background: Herbs originating from the Aconitum L. (Ranunculaceae), such as Aconitum carmichaelii Debeaux. (Wutou), Aconitum pendulum Busch. (Tiebangchui), and Aconitum kusnezoffii Reichb. (Caowu), etc. are highly valued for their medicinal properties. The roots and tubers of these herbs are commonly used to treat an array of ailments, including joint pain and tumors. The alkaloids present in them are the primary active components, with aconitine being the most notable. Aconitine has gained attention for its exceptional anti-inflammatory and analgesic properties, as well as its potential as an anti-tumor and cardiotonic agent. However, the exact process through which aconitine hinders the growth of cancerous cells and triggers their programmed cell death remains unclear. Therefore, we have undertaken a comprehensive systematic review and meta-analysis of the current research on the potential antitumor properties of aconitine. Methods: We conducted a thorough search of relevant preclinical studies in databases including PubMed, Web of Science, VIP, WanFang Data, CNKI, Embase, Cochrane Library, and National Center for Biotechnology Information (NCBI). The search was conducted up until 15 September 2022, and the data were statistically analyzed using RevMan 5.4 software. The number of tumor cell value-added, tumor cell apoptosis rate, thymus index (TI), and Bcl-2 gene expression level were the main indicators to be analyzed. Results: After applying the final inclusion criteria, a total of thirty-seven studies, comprising both in vivo and in vitro research were analyzed. The results showed that treatment with aconitine led to a significant reduction in tumor cell proliferation, a noteworthy increase in the rate of apoptosis among tumor cells, a decrease in the thymus index, and a reduction in the expression level of Bcl-2. These results suggested that aconitine could inhibit the proliferation, invasion, and migration abilities of tumor cells by regulating Bcl-2 etc., thereby enhancing the anti-tumor effects. Conclusion: In summary, our present study demonstrated that aconitine effectively reduced tumor size and volume, indicating a strong anti-tumor effect. Additionally, aconitine could increase the expression levels of caspase-3, Bax and other targets. Mechanistically, it may regulate the expression levels of Bax and Bcl-2 through the NF-κB signaling pathway, ultimately inhibiting tumor cell proliferation through autophagy.

Tandem mass tag labeled quantitative proteomic analysis of differential protein expression on total alkaloid of Aconitum flavum Hand.-Mazz. against melophagus ovinus

Melophagus ovinus disease is a common ectoparasitosis, which can lead to a decrease in animal production performance, product quality, and even death. Aconitum flavum Hand.-Mazz. has many pharmacological activities including insecticidal, heat-clearing, analgesic, and dehumidifying. However, there are few researches focused on the effects and related mechanism of Aconitum flavum Hand.-Mazz. in killing Melophagus ovinus. In this study, 11 alkaloids of Aconitum flavum Hand.-Mazz. were detected, and its total alkaloid activity was determined. The results showed when the total alkaloid concentration was 64 mg/ml and the treatment time was 16 h, the killing rate of Melophagus ovinus reached 100%. Through the observation of the differences in the surface of Melophagus ovinus in each experimental group, it was found that the morphology of the posterior end of the female Melophagus ovinus in the alkaloid treatment group was significantly different from that of the blank and positive control groups, and most of the epidermal tissue was obsessive and missing. Moreover, the enzyme activity determination results of 64 mg/ml group were significantly different when compared with the normal control group, while there was no significant difference in other groups. Then, the Melophagus ovinus gene library was established by the unreferenced genome transcriptome sequencing, the proteomic comparison was performed using tandem mass tag labeled protein detection technology, and finally, the samples were quantitatively analyzed by liquid chromatography-mass spectrometry tandem and bioinformatics methods. Based on the above experimental results, it was speculated that Aconitum flavum Hand.-Mazz. total alkaloids may cause the imbalance of protein disulfide isomerase expressions by affecting the regulation of Hsp40 cellular protein homeostasis and the oxidation of protein disulfide isomerase and related proteins. This would affect the selective recognition of signal sequence, the targeted transport of Sec 61, and the correct folding of the three-dimensional structure of amino acid chain, weakening the clearance of amino acid chains that cannot be correctly folded and eventually resulting in the killing of Melophagus ovinus. This study preliminarily revealed the mechanism of Aconitum flavum Hand.-Mazz. total alkaloids against Melophagus ovinus and provided a theoretical basis for the screening of Melophagus ovinus action targets and the development of new veterinary drugs.

An insight into current advances on pharmacology, pharmacokinetics, toxicity and detoxification of aconitine

Aconitine is a diterpenoid alkaloid, which mainly exists in the plants of Aconitum. In the last decade, a plethora of studies on the pharmacological activities of aconitine has been conducted and demonstrated that aconitine possessed an extensive range of pharmacological activities such as anti-tumor, anti-inflammatory, analgesic, local anesthesia, and immunomodulatory effects. Pharmacokinetic studies indicated that aconitine may have the characteristics of poor bioavailability, wide distribution, and slow elimination. However, studies have also found that aconitine has toxic effects on the heart, nerves, embryos, etc. Therefore, we believe that aconitine may not be suitable for heart patients and pregnant women to treat related diseases. It is important to note that all of these pharmacological effects require further high-quality studies to determine the clinical efficacy of aconitine. This review aims to summarize the advances in pharmacological, pharmacokinetics, toxicity, and detoxification of aconitine in the last decade with an emphasis on its anti-tumor and anti-inflammatory activities, to provide researchers with the latest information and point out the limitations of relevant research at the current stage and the aspects that should be strengthened in future research.

Chronic stress inhibits testosterone synthesis in Leydig cells through mitochondrial damage via Atp5a1

Stress is one of the leading causes of male infertility, but its exact function in testosterone synthesis has scarcely been reported. We found that adult male rats show a decrease in bodyweight, genital index and serum testosterone level after continual chronic stress for 21 days. Two-dimensional gel electrophoresis (2-DE) and MALDI-TOF-MS analysis identified 10 differentially expressed proteins in stressed rats compared with controls. A strong protein interaction network was found to be centred on Atp5a1 among these proteins. Atp5a1 expression significantly decreased in Leydig cells after chronic stress. Transfection of Atp5a1 siRNAs decreased StAR, CYP11A1, and 17β-HSD expression by damaging the structure of mitochondria in TM3 cells. This study confirmed that chronic stress plays an important role in testosterone synthesis by regulating Atp5a1 expression in Leydig cells.

An autofluorescence-based isolation of Leydig cells for testosterone deficiency treatment

Effective procedures for the purification of Leydig cells (LCs) can facilitate functional studies and transplantation therapies. However, current methods to purify LCs from testes are still far from satisfactory. Here, we found that testicular autofluorescence existed in the interstitium along with the gradual maturation of LCs from birth to adulthood. These autofluorescent cells were further isolated by fluorescence-activated cell sorting (FACS) and determined to be composed of LCs and macrophages. To further purify LCs, we combined two fluorescence channels of FACS and successfully separated LCs and macrophages. Of note, we confirmed that the obtained LCs not only possessed high purity, viability and quantity but also had intact steroidogenic activity and excellent responsiveness to luteinizing hormone. Moreover, subcutaneous transplantation of isolated LCs could alleviate the symptoms of testosterone deficiency in castrated mice. In summary, we established an effective autofluorescence-based method for isolating LCs. This method will aid in the future success of using LCs for basic and translational applications.

Prolonging photoperiod promotes testosterone synthesis of Leydig cells by directly targeting local melatonin system in rooster testes

The study investigated the effects of prolonging photoperiod on the synthesis of testosterone and melatonin in roosters, and the effect of melatonin on testosterone synthesis in rooster Leydig cells as well as its molecular mechanisms. We randomly divided one hundred and twenty 20-week-old roosters into three groups and provided 6, 12.5 and 16 h light, respectively. The results showed that prolonging photoperiod promoted testosterone synthesis, decreased melatonin production, and inhibited the expression of melatonin membrane receptors MEL1A, MEL1B, MEL1C, and aralkylamine n-acetyltransferase (AANAT) in rooster testes. Subsequently, rooster Leydig cells were isolated and treated with 0, 0.1, 1, 10, and 100 ng/mL melatonin for 36 h. The results suggested that melatonin inhibited testosterone synthesis in rooster Leydig cells, and silencing MEL1A and MEL1B relieved the inhibition of melatonin on testosterone synthesis. Additionally, melatonin reduced the intracellular cyclic adenosine monophosphate (cAMP) level and the phosphorylation level of cAMP-response element binding protein (CREB), and CREB overexpression alleviated the inhibition of melatonin on testosterone synthesis. Furthermore, pretreatment with cAMP activator forskolin or protein kinase A (PKA) activator 8-bromo-cAMP blocked the inhibition of melatonin on CREB phosphorylation and testosterone synthesis. These results indicated that prolonging photoperiod promoted testosterone synthesis associated with the decrease in melatonin production and membrane receptors and biosynthetic enzyme of melatonin in rooster testes, and melatonin inhibited testosterone synthesis of rooster Leydig cells by inhibiting the cAMP/PKA/CREB pathway via MEL1A and MEL1B. This may be evidence that prolonging photoperiod could promote testosterone synthesis through the inhibition of the local melatonin pathway in rooster testes.

Microcystin-LR inhibits testosterone synthesis via reactive oxygen species-mediated GCN2/eIF2α pathway in mouse testes

Previous studies demonstrated that microcystin-leucine-arginine (MC-LR) disrupted testosterone (T) synthesis, but the underlying mechanisms are not entirely elucidated. This study aims to explore the role of reactive oxygen species (ROS)-mediated GCN2/eIF2α activation on MC-LR-induced disruption of testicular T synthesis. Male mice were intraperitoneally injected with MC-LR (0 or 20 μg/kg) daily for 5 weeks. Serum T was decreased in MC-LR-exposed mice (0.626 ± 0.122 vs 24.565 ± 8.486 ng/ml, P < 0.01), so did testicular T (0.667 ± 0.15 vs 8.317 ± 1.387 ng/mg protein, P < 0.01). Steroidogenic proteins including StAR, CYP11A1 and CYP17A1 were downregulated in MC-LR-exposed mouse testes and TM3 cells. Mechanistically, p-GCN2 and p-eIF2α were elevated in MC-LR-exposed TM3 cells. GCN2iB attenuated MC-LR-induced GCN2 and eIF2α phosphorylation in TM3 cells. Moreover, GCN2iB attenuated MC-LR-induced downregulation of steroidogenic proteins in TM3 cells. Further analysis found that cellular ROS were elevated and HO-1 was upregulated in MC-LR-exposed TM3 cells. PBN rescued MC-LR-induced activation of GCN2/eIF2α signaling in TM3 cells. Additionally, pretreatment with PBN attenuated MC-LR induced downregulation of steroidogenic proteins and synthases in TM3 cells. These results suggest that ROS-mediated GCN2/eIF2α activation contributes partially to MC-LR-caused downregulation of steroidogenic proteins and synthases. The present study provides a new clue for understanding the mechanism of MC-LR-induced endocrine disruption.

Dibutyltin (DBT) inhibits in vitro androgen biosynthesis of rat immature Leydig cells

Dibutyltin (DBT) is an organotine widely applied in stabilizing plastics and de-worm poultry agents. But the effects of DBT on immature Leydig cells remain elusive. Thus, the present study aims to investigate whether in vitro exposure to DBT affects immature Leydig cell function of androgen production and delineate the underlying mechanisms. 35 days old rat immature Leydig cells were isolated and exposed to DBT at different concentrations (0, 0.1, 0.5, and 1 μM). It was found that 0.5 and 1 μM DBT lowered androgen production from immature Leydig cells under basal conditions. DBT at 1 μM lowered androgen production from immature Leydig cells under the stimulations from luteinizing hormone or 8-Br-cAMP. DBT at 1 μM lowered 22R-hydroxycholesterol and pregnenolone-mediated androgen production from immature Leydig cells. DBT at 0.1, 0.5, and 1 μM down-regulated the mRNA expression levels of Lhcgr, Star, Cyp11a1, Hsd3b1, and Nr5a1. Further investigation found that DBT at 1 μM directly inhibited CYP11A1 and 3β-HSD1 enzyme activities. In conclusion, this study told us that in vitro exposure to DBT inhibited androgen biosynthesis in immature Leydig cells by selectively interfering with the expressions and enzyme activities of CYP11A1 and 3β-HSD1.

Chlorpyrifos inhibits sperm maturation and induces a decrease in mouse male fertility

BACKGROUND

Pesticides, especially organophosphorus pesticides such as chlorpyrifos (CPF), play an important role in modern agriculture. Studies have shown that pesticide residues are an important cause of male reproductive injury in mammal.

AIM

The aim of this study was to evaluate the reproductive damage caused by CPF in male mice and investigate the underlying mechanisms.

METHODS

In vivo, C57BL/6 mice (6-8 weeks old) were treated with CPF for 14, 70, and 80 days by intraperitoneal injection, intragastric administration, and dietary supplementation, respectively. Then, sperm from the cauda epididymidis was cultured in vitro to confirm the deleterious effects of CPF.

RESULTS

The in vivo results indicated that, after treatment with CPF by dietary supplementation and intraperitoneal injection, the expression of reproduction-related genes in the mouse testes was altered, although the mice were fertile and the testes presented no morphological abnormalities. Notably, mating experiments revealed that the fertility of male mice was decreased following CPF administration by gavage. Sperm motility within the cauda epididymidis declined significantly after CPF treatment, which was accompanied by a decrease in sperm density, upregulation of relative reactive oxygen species (ROS) levels, and downregulation of glutathione reductase activity. In vitro incubation experiments showed that sperm rapidly lost their capacity for linear movement; the relative ROS levels also increased significantly, while the mitochondrial membrane potential (MMP) showed a significant decrease. However, the integrity of the plasma membrane was not affected by CPF administration.

CONCLUSIONS

The above data indicated that exposure to CPF reduces sperm motility by disrupting mitochondrial function and increasing the level of oxidative stress during sperm maturation, thereby reducing the fecundity of male mice.

Research Progress on Anti-Inflammatory Effects and Mechanisms of Alkaloids from Chinese Medical Herbs

As the spectrum of diseases keeps changing and life pace keeps going faster, the probability and frequency of diseases caused by human inflammatory reactions also keep increasing. How to develop effective anti-inflammatory drugs has become the hotspot of researches. It has been found that alkaloids from Chinese medical herbs have anti-inflammatory, analgesic, antitumor, anticonvulsant, diuretic, and antiarrhythmic effects, among which the anti-inflammatory effect is very prominent and commonly used in the treatment of rheumatoid arthritis, ankylosing spondylitis, and other rheumatic immune diseases, but its mechanism of action has not been well explained. Based on this, this paper will classify alkaloids according to structural types and review the plant sources, applicable diseases, and anti-inflammatory mechanisms of 16 kinds of alkaloids commonly used in clinical treatment, such as berberine, tetrandrine, and stephanine, with the aim of providing a reference for drug researches and clinical applications.