Transcriptome Analysis of Protection by Dendrobium Nobile Alkaloids (DNLA) against Chronic Alcoholic Liver Injury in Mice

Effects of compound Anoectochilus roxburghii (Wall.) Lindl. oral liquid on relative metabolic enzymes and various biochemical indices in Wistar rats with isoniazid-induced liver injury

Isoniazid (INH) is the first-line anti-tuberculosis drug in clinical practice, and its main adverse effect is drug-induced liver injury (DILI). This study aimed to investigate the hepatoprotective effect of Compound Anoectochilus roxburghii (Wall.) Lindl. Oral Liquid (CAROL) and to provide a new strategy for the search of potential drugs against INH-induced liver injury in Wistar rats. Animal experiment was based on INH (100 mg/kg) induced liver injury to explore the intervention effects of CAROL at doses of 1.35, 2.70, and 5.40 mL/kg. LC-QTOF-MS/MS was used to identify hepatoprotective components in CAROL and its' exposed components in rat serum. The hepatoprotective effect of CAROL was evaluated by pathological observation of rat liver tissue and changes in levels of biochemical indices and cytokines in serum or liver tissue. Of the 58 hepatoprotective components identified, 15 were detected in the serum of rats with liver-injured treated by high-dose CAROL. Results of animal experiments showed that the levels of various biochemical indexes and cytokines were significantly reversed with CAROL intervention. In particular, the expression level of cytokeratin-18 and high-mobility group box 1, as specific and sensitive indicators of DILI, was significantly reduced in the serum of rats with CAROL intervention compared with the INH model group. The same reversal was observed in the levels of TBIL, ALP, ALT, and AST in serum, as well as in the levels of TNF-α, IL-6, SOD, and MDA in liver tissue. For INH-metabolizing enzymes, an evident expression inhibition was observed in N-acetyltransferase 2 and glutathione S-transferases with CAROL intervention, which may be the key to controlling INH hepatotoxicity. CAROL has a favorable hepatoprotective effect on INH-induced liver injury. This study takes the first step in studying the hepatoprotective mechanism of CAROL against INH hepatotoxicity and provides reference for wider clinical applications.

Inhibition of mitochondrial ROS-mediated necroptosis by Dendrobium nobile Lindl. alkaloids in carbon tetrachloride induced acute liver injury

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium nobile Lindl. (DNL) is a well-known traditional Chinese medicine that has been recorded in the Chinese Pharmacopoeia (2020 edition). The previous data showed that Dendrobium nobile Lindl. alkaloids (DNLA) protect against CCl4-induced liver damage via oxidative stress reduction and mitochondrial function improvement, yet the exact regulatory signaling pathways remain undefined.

AIM OF THE STUDY

The aim of the present study was to investigate the role of necroptosis in the mode of CCl4-induced liver injury and determine whether DNLA protects against CCl4-induced acute liver injury (ALI) by inhibiting mitochondrial ROS (mtROS)-mediated necroptosis.

MATERIALS AND METHODS

DNLA was extracted from DNL, and the content was determined using liquid chromatograph mass spectrometer (LC-MS). In vivo experiments were conducted in C57BL/6J mice. Animals were administrated with DNLA (20 mg/kg/day, ig) for 7 days, and then challenged with CCl4 (20 μL/kg, ip). CCl4-induced liver injury in mice was evaluated through the assessment of biochemical indicators in mouse serum and histopathological examination of hepatic tissue using hematoxylin and eosin (H&E) staining. The protein and gene expressions were determined with western blotting and quantitative real-time PCR (RT-qPCR). Reactive oxygen species (ROS) production was detected using the fluorescent probe DCFH-DA, and mitochondrial membrane potential was evaluated using a fluorescent probe JC-1. The mtROS level was assessed using a fluorescence probe MitoSOX.

RESULTS

DNLA lessened CCl4-induced liver injury, evident by reduced AST and ALT levels and improved liver pathology. DNLA suppressed necroptosis by decreasing RIPK1, RIPK3, and MLKL phosphorylation, concurrently enhancing mitochondrial function. It also broke the positive feedback loop between mtROS and RIPK1/RIPK3/MLKL activation. Similar findings were observed with resveratrol and mitochondrial SOD2 overexpression, both mitigating mtROS and necroptosis. Further mechanistic studies found that DNLA inhibited the oxidation of RIPK1 and reduced its phosphorylation level, whereby lowering the phosphorylation of RIPK3 and MLKL, blocking necroptosis, and alleviating liver injury.

CONCLUSIONS

This study demonstrates that DNLA inhibits the necroptosis signaling pathway by reducing mtROS mediated oxidation of RIPK1, thereby reducing the phosphorylation of RIPK1, RIPK3, and MLKL, and protecting against liver injury.

Quantitative analysis of six sesquiterpene glycosides from Dendrobium nobile Lindl. under different growth conditions by high-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry in MRM mode

INTRODUCTION

The sesquiterpene glycosides (SGs) from Dendrobium nobile Lindl. have immunomodulatory effects. However, there are no studies on the growth conditions affecting its contents and quantitative analysis methods.

OBJECTIVE

In the present study, a quantitative analysis method for six SGs from D. nobile was established. We explored which growth conditions could affect the contents of SGs, providing a basis for the cultivation and clinical application of D. nobile.

METHODS

Firstly, based on the optimization of mass spectrometry parameters and extraction conditions for six SGs in D. nobile, a method for the determination of the contents of six SGs was established using high-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (HPLC-QqQ-MS/MS) in multiple reaction monitoring (MRM) mode. Then, the methodology of the established method was validated. Secondly, the established method was applied to determine the contents of six SGs from 78 samples of D. nobile grown under different growth conditions. Finally, chemometrics analysis was employed to analyze the results and select optimal growth conditions for D. nobile.

RESULTS

The results indicated significant variations in the contents of SGs from D. nobile grown under different growth conditions. The primary factors influencing SG contents included age, geographical origin, altitude, and epiphytic pattern.

CONCLUSION

Therefore, the established method for determining SG contents from D. nobile is stable. In particular, the SG contents were relatively high in samples of 3-year-old D. nobile grown at an altitude of approximately 500 m on Danxia rocks in Chishui, Guizhou.

PPARα is one of the key targets for dendrobine to improve hepatic steatosis in NAFLD

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium nobile Lindl. (DNL) is a traditional Chinese ethnobotanical herb. Dendrobine (DNE) has been designated as a quality indicator for DNL in the Chinese Pharmacopoeia. DNE exhibits various pharmacological activities, including the reduction of blood lipids, regulation of blood sugar levels, as well as anti-inflammatory and antioxidant properties.

AIM OF THE STUDY

The objective of this study is to explore the impact of DNE on lipid degeneration in nonalcoholic fatty liver disease (NAFLD) liver cells and elucidate its specific mechanism. The findings aim to offer theoretical support for the development of drugs related to DNL.

MATERIALS AND METHODS

We utilized male C57BL/6J mice, aged 6 weeks old, to establish a NAFLD model. This model allowed us to assess the impact of DNE on liver pathology and lipid levels in NAFLD mice. We investigated the mechanism of DNE's regulation of lipid metabolism through RNA-seq analysis. Furthermore, a NAFLD model was established using HepG2 cells to further evaluate the impact of DNE on the pathological changes of NAFLD liver cells. The potential mechanism of DNE's improvement was rapidly elucidated using HT-qPCR technology. These results were subsequently validated using mouse liver samples. Following the in vitro activation or inhibition of PPARα function, we observed changes in DNE's ability to ameliorate pathological changes in NAFLD hepatocytes. This mechanism was further verified through RT-qPCR and Western blot analysis.

RESULTS

DNE demonstrated a capacity to enhance serum TC, TG, and liver TG levels in mice, concurrently mitigating liver lipid degeneration. RNA-seq analysis unveiled that DNE primarily modulates the expression of genes related to metabolic pathways in mouse liver. Utilizing HT-qPCR technology, it was observed that DNE markedly regulates the expression of genes associated with the PPAR signaling pathway in liver cells. Consistency was observed in the in vivo data, where DNE significantly up-regulated the expression of PPARα mRNA and its protein level in mouse liver. Additionally, the expression of fatty acid metabolism-related genes (ACOX1, CPT2, HMGCS2, LPL), regulated by PPARα, was significantly elevated following DNE treatment. In vitro experiments further demonstrated that DNE notably ameliorated lipid deposition, peroxidation, and inflammation levels in NAFLD hepatocytes, particularly when administered in conjunction with fenofibrate. Notably, the PPARα inhibitor GW6471 attenuated these effects of DNE.

CONCLUSIONS

In summary, DNE exerts its influence on the expression of genes associated with downstream fat metabolism by regulating PPARα. This regulatory mechanism enhances liver lipid metabolism, mitigates lipid degeneration in hepatocytes, and ultimately ameliorates the pathological changes in NAFLD hepatocytes.