The molecular characteristics in different procedures of spermatogenesis

Spermatogenesis is a multistep biological process. In addition to somatic cells, it involves the orderly differentiation of dozens of spermatogenic cells. In this process, the regulatory networks between different spermatogenic cell populations are significantly different. RNA m6A regulators and miRNAs have been found to be closely related to spermatogenesis in recent years, and they are an important part of the above regulatory networks. Understanding gene expression and its rules in different spermatogenic cell populations will help in the in-depth exploration of their detailed roles in spermatogenesis. This study collected a public dataset of nonobstructive azoospermia (NOA). Based on the Johnson score, the testicular samples of NOA were divided into three types, Sertoli-cell only syndrome, meiotic arrest and postmeiotic arrest, which represented the loss of three germ cell populations, including whole spermatogenic cells, postmeiotic spermatogenic cells, and a mixture of late spermatids and spermatozoa, respectively. The aforementioned three types of testis data were compared with normal testis data, and the molecular expression characteristics of the abovementioned three germ cell populations were obtained. Our study showed that different germ cell populations have different active molecules and their pathways. In addition, RNA m6A regulators, including METTL3, IGF2BP2 and PRRC2A, and miRNAs, including hsa-let-7a-2, hsa-let-7f-1, hsa-let-7g, hsa-miR-15a, hsa-miR-197, hsa-miR-21, hsa-miR-30e, hsa-miR-32, hsa-miR-503 and hsa-miR-99a, also presented regulatory roles in almost all germ cells.

Cinnamaldehyde Regulates the Generation of γ-aminobutyric Acid to Exert Sedation via Irreversible Inhibition of ENO1 in the Cerebellar Granular Layer

SCOPE

Glutamate (Glu) and γ-aminobutyric acid (GABA) are the major excitatory and inhibitory neurotransmitters that control information flow in the brain. GABA dysfunction is a general vulnerability factor for mental illness. Cinnamaldehyde (CA) is found to have sedation in a mental illness model. However, the specific targets and molecular mechanisms related to the sedative effects of CA have not been elucidated.

METHODS AND RESULTS

Metabolomics analysis and target fishing showed CA could increase the expression of GABA in vivo, and α-enolase (ENO1) is the primary target protein of CA associated with sedation. CA mainly binds with ENO1 in the cerebellar granular layer of brain, which influences the first transformations of the input signals arriving in the cerebellar cortex. The α,β-unsaturated aldehyde group of CA blocks the hydroxy group of Ser40, which induces a loss in ENO1 activation. CA also disturbs the glycolysis pathway and influences the tricarboxylic acid cycle and oxidative phosphorylation, which activate gluconeogenesis to provide energy to the brain. This mechanism is verified in zebrafish with ENO1 or glutamic acid decarboxylase (GAD) deficiency.

CONCLUSIONS

CA demonstrates sedation and alleviates GABA dysfunction via covalent binding ENO1, which shows the potential to improve the therapy of mental illness.

Vision-Related Quality of Life and Association Between Retinal Parameters in Patients with Non-Arteritic Anterior Ischemic Optic Neuropathy

Purpose

To evaluate visual-related quality of life (VR-QoL) and its association with optic nerve head microvasculature in individuals with nonarteritic anterior ischemic optic neuropathy (NAION) evaluated at the acute stage.

Methods

In this retrospective case-control study, 23 NAION eyes at the acute stage and 25 age and gender matched healthy eyes were included, respectively. All included eyes underwent a complete ophthalmic examination including optical coherence tomography (OCT) and OCT angiography (OCTA). The Chinese version of the National Eye Institute Visual Function Questionnaire-25 (CHI-NEI-VFQ-25) was applied to assess VR-QoL in individuals consecutively visited at an ophthalmic center. Descriptive and analytic statistics were employed.

Results

There were no significant differences on age, gender, socioeconomic and education level (P > 0.05), but best-corrected visual acuity (BCVA) differences were reported between cases and controls (P < 0.05). Each peripapillary retinal nerve fiber layer (RNFL) thickness was higher but peripapillary vessel density (VD) and VR-QoL scores for all subscales were significantly lower in cases when compared with controls, respectively (P < 0.05). Particularly, pearson's partial correlation analysis restricted to eyes with NAION revealed stronger correlations between peripapillary RNFL measurements, VD and VR-QoL.

Conclusion

NAION at the acute stage affects VR-QoL in Chinese individuals. Some peripapillary RNFL measurements and VD correlated with VR-QoL. Retinal anatomic and blood flow examinations and inventions in patients with NAION are necessary to facilitate VR-QoL and disease control.

Magnolol and honokiol target TRPC4 to regulate extracellular calcium influx and relax intestinal smooth muscle

ETHNOPHARMACOLOGICAL RELEVANCE

Magnolia officinalis Cortex (M. officinalis) is a classical traditional Chinese medicine (TCM) widely used to treat digestive system diseases. It effectively regulates gastrointestinal motility to improve abdominal pain, abdominal distension and other symptoms. Magnolol (MAG) and honokiol (HON) are the main pharmacodynamic components responsible for the gastrointestinal activity of M. officinalis.

AIM OF THE STUDY

The transient receptor potential (TRP) family is highly expressed in the gastrointestinal tract and participates in the regulation of gastrointestinal motility, visceral hypersensitivity, visceral secretion and other physiological activities. In this study, the calcium-lowering mechanisms of MAG and HON contributing to the smooth muscle relaxation associated with TRP are discussed.

MATERIALS AND METHODS

The relaxation smooth muscle effects of MAG and HON were tested by the isolated intestine tone tests. A synthetic MAG probe (MAG-P) was used to target fishing for their possible target. The distribution of MAG on the smooth muscle was identified by a molecular tracer based on chemical biology. Ca²⁺ imaging and dual-luciferase reporter assays were used to determine the effects on the target proteins. Finally, the calcium-mediating effects of MAG and HON on smooth muscle cells and TRPC4-knockdown cells were compared to verify the potential mechanism.

RESULTS

After confirming the smooth muscle relaxation in the small intestine induced by MAG and HON, the relaxation effect was identified mainly due to the downregulation of intracellular calcium by controlling external calcium influx. Although MAG and HON inhibited both TRPV4 and TRPC4 channels to reduce calcium levels, the inhibitory effect on TRPC4 channels is an important mechanism of their smooth muscle relaxation effect, since TRPC4 is widely expressed in the small intestinal smooth muscle cells.

CONCLUSIONS

The inhibition of MAG and HON on TRPC4 channels contributes to the relaxation of intestinal smooth muscle.

Effect of Sn on the CO Catalytic Activity and Water Resistance of Cu-Mn Catalyst

In view of the problem that excessive CO in underground coal mine space can easily lead to a large number of casualties, Cu-Mn-Sn water-resistant eliminators with different Sn contents were prepared by a co-precipitation method. The activity of the eliminators was analyzed by using an independently developed activity testing platform, N₂ adsorption and desorption, XRD, SEM, XPS, and FTIR to characterize the activity factors and water resistance. The results showed that Cu-Mn-Sn-20 with 20% Sn content had the highest activity, which was 3.23 times that of Cu-Mn. The main reason for the increased activity is that Cu-Mn-Sn-20 doped with 20% Sn provides a larger specific surface area and more active sites and reduces the pore size, so that the crystallization degree of Cu_1.4Mn_1.5O₄ is lower. The doping of 20% Sn reduces the absorption of lattice water and coordination water and improves the water resistance of Cu-Mn-Sn-type eliminators. The Cu-Mn-Sn-20 water-resistant eliminator is used to quickly eliminate CO in underground coal mines, which is of great significance for the rescue workers in underground coal mines after disasters.

Multi-omics analysis reveals the mechanisms of action and therapeutic regimens of traditional Chinese medicine, Bufei Jianpi granules: Implication for COPD drug discovery

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) is a serious public health challenge in the world. According to the treatment instructions by Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2020, bronchiectasis combine with inhaled corticosteroids and long-acting anti-muscarinic agents were recommended as the main prescription. However, this symptomatic treatment still has ineluctable limits because it ignored the most pathogenesis mechanism of COPD. As an alternative traditional Chinese medicine (TCM) for COPD, Bufei Jianpi granules (BJG) can reduce the frequency and duration of acute exacerbation in COPD patients and improve their quality of life. The evidence demonstrated BJG acts as therapeutics that retarding the airway remodeling process, eliminating phlegm, thrombolysis and improving mitochondrial function. However, the detailed molecular mechanism is still urgently revealed.

PURPUSE

In this study, we aim to find out the active pharmacodynamic ingredients and reveal the treatment mechanism of active pharmacodynamic ingredients.

METHODS

Based on the pharmacodynamic evaluation and chemomic profiling of BJG in COPD rats, an integrated multi-omics analysis was performed, including molecular networking, metabonomics, proteomics and bioinformatics. Moreover, focus on the active compounds, we verified the molecular core mechanism by molecular biology methods.

RESULTS

Pachymic acid, shionone, peiminine and astragaloside A was verified as therapeutic agents for improving the condition of COPD by acting on the EGFR, ERK1, PAI-1 and p53 target, respectively.

CONCLUSION

In this study, our findings indicated that some compounds in BJG alleviates the pathological process of COPD, which is related to regulating lung function, mucus production, pulmonary embolism and energy metabolism and this will be a benefit complementary to GOLD guidelines.

Okicamelliaside targets the N-terminal chaperone pocket of HSP90 disrupts the chaperone protein interaction of HSP90-CDC37 and exerts antitumor activity

Heat shock protein 90 (HSP90) has been recognized as a crucial target in cancer cells. However, various toxic reactions targeting the ATP binding site of HSP90 may not be the best choice for HSP90 inhibitors. In this paper, an ellagic acid derivative, namely, okicamelliaside (OCS), with antitumor effects was found. To identify potential anti-cancer mechanisms, an OCS photosensitive probe was applied to target fishing and tracing. Chemical proteomics and protein-drug interaction experiments have shown that HSP90 is a key target for OCS, with a strong binding affinity (K_D = 6.45 μM). Mutation analysis of the target protein and molecular dynamics simulation revealed that OCS could competitively act on the key Glu-47 site at the N-terminal chaperone pocket of HSP90, where the co-chaperone CDC37 binds to HSP90, affect its stability and reduce the ∆G_bind of HSP90-CDC37. It was demonstrated that OCS destroys the protein-protein interactions of HSP90-CDC37; selectively affects downstream kinase client proteins of HSP90, including CDK4, P-AKT⁴⁷³, and P-ERK1/2; and exerts antitumor effects on A549 cells. Furthermore, tumor xenograft experiments demonstrated high antitumor activity and low toxicity of OCS in the same way. Our findings identified a novel N-terminal chaperone pocket natural inhibitor of HSP90, that is, OCS, which selectively inhibits the formation of the HSP90-CDC37 protein complex, and provided further insight into HSP90 inhibitors for anti-cancer candidate drugs.

Exogenous citric acid enhances drought tolerance in tobacco (Nicotiana tabacum)

Organic acids play a pivotal role in improving plant response to long-term drought stress. External application of organic acids has been reported to improve drought resistance in several species. However, whether organic acids have similar effects in tobacco remains unknown. A screening study of the protective function of organic acids in tobacco and understanding the underlying molecular mechanism would be useful in developing a strategy for drought tolerance. Several physiological and molecular adaptations to drought including abscisic acid, stomatal closure, reactive oxygen species homeostasis, amino acid accumulation, and drought-responsive gene expression were observed by exogenous citric acid in tobacco plants. Exogenous application of 50 mm citric acid to tobacco plants resulted in higher chlorophyll content, net photosynthesis, relative water content, abscisic acid content and lower stomatal conductance, transpiration and water loss under drought conditions. Moreover, reactive oxygen species homeostasis was better maintained through increasing activity of antioxidant enzymes and decreasing hydrogen peroxide content after citric acid pretreatment under drought. Amino acids involved in the TCA cycle accumulated after external application of citric acid under drought stress. Furthermore, several drought stress-responsive genes also dramatically changed after application of citric acid. These data support the idea that external application of citric acid enhances drought resistance by affecting physiological and molecular regulation in tobacco. This study provides clear insights into mechanistic details of regulation of amino acid and stress-responsive gene expression by citric acid in tobacco in response to drought, which is promising for minimizing growth inhibition in agricultural fields.

LS-106, a novel EGFR inhibitor targeting C797S, exhibits antitumor activities both in vitro and in vivo

With the wide clinical use of the third-generation epidermal growth factor receptor (EGFR) inhibitor osimertinib for the treatment of EGFR-mutated non-small cell lung cancer (NSCLC), acquired resistance caused by EGFR C797S tertiary mutation has become a concern. Therefore, fourth-generation EGFR inhibitors that could overcome this mutation have gained increasing attention in recent years. Here, we identified LS-106 as a novel EGFR inhibitor against C797S mutation and evaluated its antitumor activity both in vitro and in vivo. In cell-free assay, LS-106 potently inhibited the kinase activities of EGFR19del/T790M/C797S and EGFRL858R/T790M/C797S with IC50 values of 2.4 nmol/L and 3.1 nmol/L, respectively, which was more potent than osimertinib. Meanwhile, LS-106 exhibited comparable kinase inhibitory effect to osimertinib on EGFRL858R/T790M and wild-type EGFR. Results from cellular experiments demonstrated that LS-106 potently blocked the phosphorylation of EGFR C797S triple mutations in the constructed BaF3 cells that highly expressed EGFR19del/T790M/C797S or EGFRL858R/T790M/C797S , and thus inhibited the proliferation of these cells. We also constructed tumor cells harboring EGFR19del/T790M/C797S (named PC-9-OR cells) using the CRISPR/Cas9 system and found that LS-106 markedly suppressed the activation of EGFR19del/T790M/C797S and the proliferation of PC-9-OR cells. Moreover, cells harboring EGFR19del/T790M/C797S underwent remarkable apoptosis upon LS-106 treatment. In vivo experiments further demonstrated that oral administration of LS-106 caused significant tumor regression in a PC-9-OR xenograft model, with a tumor growth inhibition rate (TGI) of 83.5% and 136.6% at doses of 30 and 60 mg/kg, respectively. Taken together, we identified LS-106 as a novel fourth-generation EGFR inhibitor against C797S mutation and confirmed its preclinical antitumor effects in C797S-triple-mutant tumor models.

GSH-Responsive Drug Delivery System for Active Therapy and Reducing the Side Effects of Bleomycin

The application of drug delivery system (DDS) has achieved breakthroughs in many aspects, especially in the field of tumor treatment. In this work, polyethylene glycol (PEG)-modified hollow mesoporous manganese dioxide (HMnO₂@PEG) nanoparticles were used to load the anti-tumor drug bleomycin (BLM). When the DDS reached the tumor site, HMnO₂@PEG was degraded and reduced to Mn²⁺ by the overexpression of glutathione in the tumor microenvironment, and the drug was released simultaneously. BLM coordinated with Mn²⁺ in situ, thereby greatly improving the therapeutic activity of BLM. The results of in vivo and in vitro treatment experiments showed that the DDS had excellent responsive therapeutic activation ability. In addition, Mn²⁺ exhibited strong paramagnetism and was used for T₁-weighted magnetic resonance imaging in vivo. Furthermore, this therapeutic mode of responsively releasing drugs and activating in situ effectively attenuated pulmonary fibrosis initiated by BLM. In short, this DDS could help in avoiding the side effects of drugs.

Atractylenolide-I covalently binds to CYP11B2, selectively inhibits aldosterone synthesis, and improves hyperaldosteronism

Hyperaldosteronism is a common disease that is closely related to endocrine hypertension and other cardiovascular diseases. Cytochrome P450 11B2 (CYP11B2), an important enzyme in aldosterone (ALD) synthesis, is a promising target for the treatment of hyperaldosteronism. However, selective inhibitors targeting CYP11B2 are still lacking due to the high similarity with CYP11B1. In this study, atractylenolide-I (AT-I) was found to significantly reduce the production of ALD but had no effect on cortisol synthesis, which is catalyzed by CYP11B1. Chemical biology studies revealed that due to the presence of Ala320, AT-I is selectively bound to the catalytic pocket of CYP11B2, and the C8/C9 double bond of AT-I can be epoxidized, which then undergoes nucleophilic addition with the sulfhydryl group of Cys450 in CYP11B2. The covalent binding of AT-I disrupts the interaction between heme and CYP11B2 and inactivates CYP11B2, leading to the suppression of ALD synthesis; AT-I shows a significant therapeutic effect for improving hyperaldosteronism.

Phenotype-Based HPLC-Q-TOF-MS/MS Coupled With Zebrafish Behavior Trajectory Analysis System for the Identification of the Antidepressant Components in Methanol Extract of Anshen Buxin Six Pills

Phenotype screening has become an important tool for the discovery of active components in traditional Chinese medicine. Anshen Buxin Six Pills (ASBX) are a traditional Mongolian medicine used for the treatment of neurosis in clinical settings. However, its antidepressant components have not been explicitly identified and studied. Here, the antidepressant effect of ASBX was evaluated in adult zebrafish. High performance liquid chromatography-mass spectrometry (HPLC-Q-TOF-MS/MS) was combined with zebrafish behavior trajectory analysis to screen and identify the antidepressant-active extract fraction and active components of ASBX. Finally, the antidepressant effect of the active ingredients were verified by the behavior, pathology, biochemical indices and protein level of adult fish. The novel tank driving test (NTDT) showed that ASBX can effectively improve the depressive effect of reserpine on zebrafish. Petroleum ether and dichloromethane extracts of ASBX were screened as antidepressant active extracts. Costunolide (COS) and dehydrocostus lactone (DHE) were screened as the active components of ASBX. COS had been shown to significantly improve the depressive behavior, nerve injury and neurotransmitter levels (5-hydroxytryptamine (5-HT) and norepinephrine (NE)) of zebrafish by inhibiting the high expression of serotonin transporter and norepinephrine transporter induced by reserpine suggesting the antidepressant effect of COS may be related to its effect on 5-HT and NE pathways. This study provided a phenotype based screening method for antidepressant components of traditional Chinese medicines, so as to realize the separation, identification and activity screening of components at the same time.

The rich pharmacological activities of Magnolia officinalis and secondary effects based on significant intestinal contributions

ETHNOPHARMACOLOGICAL RELEVANCE

Magnolia officinalis Cortex (M. officinalis) is a traditional herbal drug widely used in Asian countries. Depending on its multiple biological activities, M. officinalis is used to regulate gastrointestinal (GI) motility, relieve cough and asthma, prevent cardiovascular and cerebrovascular diseases, and treat depression and anxiety.

AIM OF THE REVIEW

We aimed to review the abundant form of pharmacodynamics activity and potential mechanisms of action of M. officinalis and the characteristics of the internal processes of the main components. The potential mechanisms of local and distance actions of M. officinalis based on GI tract was provided, and it was used to reveal the interconnections between traditional use, phytochemistry, and pharmacology.

MATERIALS AND METHODS

Published literatures about M. officinalis and its main components were collected from several scientific databases, including PubMed, Elsevier, ScienceDirect, Google Scholar and Web of Science etc. RESULTS: M. officinalis was shown multiple effects including effects on digestive system, respiratory system, central system, which is consistent with traditional applications, as well as some other activities such as cardiovascular system, anticancer, anti-inflammatory and antioxidant effects and so on. The mechanisms of these activities are abundant. Its chief ingredients such as magnolol and honokiol can be metabolized into active metabolites in vivo, which can increase water solubility and bioavailability and exert pharmacological activity in the whole body. In the GI tract, M. officinalis and its main ingredient can regulate GI hormones and substance metabolism, protect the intestinal barrier and affect the gut microbiota (GM). These actions are effective to improve local discomfort and some distal symptoms such as depression, asthma, or metabolic disorders.

CONCLUSIONS

Although M. officinalis has rich pharmacological effects, the GI tract makes great contributions to it. The GI tract is not only an important place for absorption and metabolism but also a key site to help M. officinalis exert local and distal efficacy. Pharmacodynamical studies on the efficacies of distal tissues based on the contributions of the GI tract hold great potential for understanding the benefits of M. officinalis and providing new ideas for the treatment of important diseases.

A new nomogram for the prediction of bone metastasis in patients with prostate cancer

Objective

This study aimed to establish a new prognostic nomogram for bone metastasis in patients with prostate cancer (PCa).

Methods

This study retrospectively analyzed clinical data from 332 patients diagnosed with PCa from 2014 to 2019, and patients were randomly divided into a training set (n = 184) and a validation set (n = 148). Multivariate logistic regression analysis was used to establish a prediction model based on the training set, and a nomogram was constructed for visual presentation. The calibration, discrimination and clinical usefulness of the model were evaluated using the validation set.

Results

Total prostate-specific antigen, clinical tumor stage, Gleason score, prostate volume, red cell distribution width and serum alkaline phosphatase were selected as predictors to develop a prediction model of bone metastasis. After evaluation, the model developed in our study exhibited good discrimination (area under the curve: 0.958; 95% confidence interval: 0.93–0.98), calibration (U = 0.01) and clinical usefulness.

Conclusions

The new proposed model showed high accuracy for bone metastasis prediction in patients with PCa and good clinical usefulness.

Seeking help by parents for care regarding the socio-emotional development of preschool children

Background

Timely parental help-seeking regarding their child's socio-emotional development is associated with a lower rate and lower severity of psychosocial problems in later life. This study aimed to examine factors associated with parental help-seeking for the socio-emotional development of 3-year-old children.

Methods

Data of parents and children (n = 1507) from a community sample was analyzed. Thirteen potentially related factors were assessed at baseline at child age 2 years, and classified according to Andersen's Behavioral Model: predisposing, enabling, and need factors. Parental help-seeking and 14 formal and informal care (e.g. General practitioner, internet) used in the past 12 months were measured at follow-up at child age 3 years. Logistic regression was applied.

Results

In total, 22.6% of parents reported help-seeking for socio-emotional development of their 3-year-old child; 6.8% addressed formal care and 17.5% addressed informal care. General practitioner (2.7%) and family (12.5%) were the most frequently used formal and informal care, respectively. Among predisposing factors associated with a higher odds of parental help-seeking were child's other western background (OR = 1.66, 95%CI: 1.02-2.68) and parental age = &lt; 29 years old (OR = 1.71, 95%CI: 1.01-2.92). No associated factors were found among enabling factors. The need factors associated with a higher odds of parental help-seeking were having previous help-seeking (OR = 2.52, 95%CI: 1.83-3.48) and discussing child's socio-emotional development in the well-child visit (OR = 2.47, 95%CI: 1.73-3.53).

Conclusions

Predisposing and need factors were associated with parental help-seeking for socio-emotional development of 3-years-old child. The findings can be used to further develop support for parents accessing adequate information, prevention and anticipatory care with regard to the child's socio-emotional development.

Key messages

The study longitudinally investigated parental help-seeking for socio-emotional development of their 3-year old children in a large community sample. The study makes an important contribution to the existing literature on this topic because of its particularly young sample of 3-year-old children.

Discovery and structure - activity relationship exploration of pyrazolo[1,5-a]pyrimidine derivatives as potent FLT3-ITD inhibitors

Internal tandem duplications of FLT3 (FLT3-ITD) occur in approximately 25% of all acute myeloid leukemia (AML) cases and confer a poor prognosis. Optimization of the screening hit 1 from our in-house compound library led to the discovery of a series of pyrazolo[1,5-a]pyrimidine derivatives as potent and selective FLT3-ITD inhibitors. Compounds 17 and 19 displayed potent FLT3-ITD activities both with IC₅₀ values of 0.4 nM and excellent antiproliferative activities against AML cell lines. Especially, compounds 17 and 19 inhibited the quizartinib resistance- conferring mutations, FLT3^D835Y, both with IC₅₀ values of 0.3 nM. Moreover, western blot analysis indicated that compounds 17 and 19 potently inhibited the phosphorylation of FLT3 and attenuated downstream signaling in AML cells. These results indicated that pyrazolo[1,5-a]pyrimidine derivatives could be promising FLT3-ITD inhibitors for the treatment AML.

Small-Molecule Fluorogenic Probe for the Detection of Mitochondrial Temperature In Vivo

Mitochondria, as energy factories, participate in many metabolic processes and play vital roles in cell life. Most human diseases are caused by mitochondrial dysfunction, and mitochondrial temperature is an important indicator of mitochondrial function. Despite the biological importance of mitochondria, there are few tools for detecting changes in mitochondrial temperature in living organisms. Here, we report on a thermosensitive rhodamine B (RhB)-derived fluorogenic probe (RhBIV) that enables fluorescent labeling of cell mitochondria at concentrations as low as 1 μM. We demonstrate that this probe exhibits a temperature-dependent response in cell mitochondria. Furthermore, in mice, it has a long half-life (t_1/2) and is primarily enriched in the liver. This unique thermosensitive probe offers a simple, nondestructive method for longitudinal monitoring of mitochondrial temperature both in vitro and in vivo to elucidate fundamental physiological and pathological processes related to mitochondrial function.

Ursolic acid reduces hepatocellular apoptosis and alleviates alcohol-induced liver injury via irreversible inhibition of CASP3 in vivo

Alcoholic liver disease (ALD) is one of the pathogenic factors of chronic liver disease with the highest clinical morbidity worldwide. Ursolic acid (UA), a pentacyclic terpenoid carboxylic acid, has shown many health benefits including antioxidative, anti-inflammatory, anticancer, and hepatoprotective activities. We previously found that UA was metabolized in vivo into epoxy-modified UA containing an epoxy electrophilic group and had the potential to react with nucleophilic groups. In this study we prepared an alkynyl-modified UA (AM-UA) probe for tracing and capturing the target protein of UA from liver in mice, then investigated the mode by which UA bound to its target in vivo. By conducting proteome identification and bioinformatics analysis, we identified caspase-3 (CASP3) as the primary target protein of UA associated with liver protection. Molecule docking analysis showed that the epoxy group of the UA metabolite reacted with Cys-163 of CASP3, forming a covalent bond with CASP3. The binding mode of the UA metabolites (UA, CM-UA, and EM-UA) was verified by biochemical evaluation, demonstrating that the epoxy group produced by metabolism played an important role in the inhibition of CASP3. In alcohol-treated HepG2 cells, pretreatment with the UA metabolite (10 μM) irreversibly inhibited CASP3 activities, and subsequently decreased the cleavage of PARP and cell apoptosis. Finally, pre-administration of UA (20-80 mg· kg-1 per day, ig, for 1 week) dose-dependently alleviated alcohol-induced liver injury in mice mainly via the inhibition of CASP3. In conclusion, this study demonstrates that UA is a valuable lead compound for the treatment of ALD.