Predictive Modeling of MAFLD Based on Hsp90α and the Therapeutic Application of Teprenone in a Diet-Induced Mouse Model

Short-term dietary teprenone improved thermal tolerance and mitigated liver damage caused by heat stress in juvenile largemouth bass (Micropterus salmoides)

Heat stress seriously threatens fish survival and health, demanding immediate attention. Teprenone is a gastric mucosal protective agent that can induce heat shock protein expression. This research investigated the effects of teprenone on largemouth bass (Micropterus salmoides) subjected to heat stress. Juvenile fish were assigned to different groups: group C (control group, 0 mg teprenone/kg diet), T0, T200, T400, and T800 (0, 200, 400, and 800 mg teprenone/kg diet, respectively), which were fed for 3 days, followed by a day without the diet. All groups except group C were subjected to acute heat stress (from 24 °C to 35 °C at 1 °C per hour and then maintained at 35 °C for 3 h). The results were as follows: The critical thermal maxima were significantly higher in the T200, T400, and T800 groups compared with the T0 group (P < 0.05). Heat stress caused severe damage to the tissue morphology of the liver, while teprenone significantly reduced this injury (P < 0.05). Serum cortisol concentration decreased gradually as teprenone concentration increased, and the lowest concentration was observed in the T800 group (P < 0.05). Compared with the T0 group, the serum activities of aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyl transferase were significantly lower in the T200, T400, and T800 groups (P < 0.05). The liver activities of catalase, total superoxide dismutase, and peroxidase were significantly higher in the T200 group than in the T0 group (P < 0.05). Transcript levels of the heat shock proteins (hsp90, hsp70, hspa5, and hsf1) and caspase family (caspase3 and caspase9) in the liver of the T200 group were significantly higher than those of the T0 group (P < 0.05). Western blot results showed that HSP70 and HSPA5 in the liver were significantly upregulated in the T200 group compared with the T0 group (P < 0.05). In summary, dietary teprenone improved thermal tolerance, alleviated heat stress damage in the liver, enhanced antioxidant capacity, and upregulated heat shock proteins in juvenile largemouth bass. This study offers theoretical support for applying teprenone in aquaculture to reduce financial losses caused by abiotic factors.

HRD1-mediated ubiquitination of HDAC2 regulates PPARα-mediated autophagy and alleviates metabolic-associated fatty liver disease

BACKGROUND

Metabolic-associated fatty liver disease (MAFLD) is a leading cause of chronic liver disease worldwide. Autophagy plays a pivotal role in lipid metabolism; however, the mechanism underlying the reduced autophagic activity in MAFLD remains elusive.

METHODS

Autophagy was monitored by TUNEL assay and immunofluorescence staining of LC3. The expression of autophagy-related proteins, PPARα, HDAC2, and HRD1 was detected by Western blot. The association between HDAC2 and PPARα promoter was assessed by chromatin immunoprecipitation (ChIP) and dual-luciferase assays, and the HRD1-mediated ubiquitin-proteasomal degradation of HDAC2 was detected by co-immunoprecipitation (co-IP). The in vitro findings were validated in a hypoxia-induced MAFLD mouse model. Histological changes, fibrosis, and apoptosis in liver tissues were detected by hematoxylin and eosin staining, Masson's trichrome staining, and TUNEL assay. The immunoreactivities of key molecules were examined by IHC analysis.

RESULTS

Hypoxia-suppressed autophagy in hepatocytes. Hypoxic exposure downregulated HRD1 and PPARα, while upregulating HDAC2 in hepatocytes. Overexpression of PPARα promoted hepatic autophagy, while knocking down HDAC2 or overexpressing HRD1 reduced hypoxia-suppressed autophagy in hepatocytes. Mechanistically, HDAC2 acted as a transcriptional repressor of PPARα, and HRD1 mediated the degradation of HDAC2 through the ubiquitin-proteasome pathway. Functional studies further showed that hypoxia-suppressed hepatic autophagy via the HRD1/HDAC2/PPARα axis in vitro and in vivo.

CONCLUSION

HRD1-mediated ubiquitination of HDAC2 regulates PPARα-mediated autophagy and ameliorates hypoxia-induced MAFLD.

Effect of Calebin-A on Critical Genes Related to NAFLD: A Protein-Protein Interaction Network and Molecular Docking Study

Background

Calebin-A is a minor phytoconstituent of turmeric known for its activity against inflammation, oxidative stress, cancerous, and metabolic disorders like Non-alcoholic fatty liver disease(NAFLD). Based on bioinformatic tools. Subsequently, the details of the interaction of critical proteins with Calebin-A were investigated using the molecular docking technique.

Methods

We first probed the intersection of genes/ proteins between NAFLD and Calebin-A through online databases. Besides, we performed an enrichment analysis using the ClueGO plugin to investigate signaling pathways and gene ontology. Next, we evaluate the possible interaction of Calebin-A with significant hub proteins involved in NAFLD through a molecular docking study.

Results

We identified 87 intersection genes Calebin-A targets associated with NAFLD. PPI network analysis introduced 10 hub genes (TP53, TNF, STAT3, HSP90AA1, PTGS2, HDAC6, ABCB1, CCT2, NR1I2, and GUSB). In KEGG enrichment, most were associated with Sphingolipid, vascular endothelial growth factor A (VEGFA), C-type lectin receptor, and mitogen-activated protein kinase (MAPK) signaling pathways. The biological processes described in 87 intersection genes are mostly concerned with regulating the apoptotic process, cytokine production, and intracellular signal transduction. Molecular docking results also directed that Calebin-A had a high affinity to bind hub proteins linked to NAFLD.

Conclusion

Here, we showed that Calebin-A, through its effect on several critical genes/ proteins and pathways, might repress the progression of NAFLD.

Kaempferol exerts antioxidant effects in age-related diminished ovarian reserve by regulating the HSP90/NRF2 pathway

Kaempferol is the active ingredient of Er-Xian decoction (EXD), a traditional Chinese medicine formula used clinically to treat ovarian dysfunction, but the mechanism of kaempferol relieving age-related diminished ovarian reserve (AR-DOR) is still unclear. In this study, 36 volunteers and 78 DOR patients (37 patients with EXD treatment) were enrolled in the clinical research. Meanwhile, 32-week-old female mice were used to establish the AR-DOR model, and these model mice were intragastrically administered with 100 mg/kg kaempferol in the presence or absence of 200 mg/kg geranylgeranylacetone (GGA) or 1 mg/kg geldanamycin (GDA). The effects of kaempferol on serum hormone levels and oxidative stress-related indexes were detected by enzyme-linked immunosorbent assay. Antral follicle count (AFC) was determined by hematoxylin-eosin staining. The protein levels of HSP90 and nuclear factor erythroid 2-related factor 2 (NRF2) were assayed by Western blot. This study displayed that the serum anti-Mullerian hormone (AMH) level in DOR patients with EXD treatment was higher than that in DOR patients without EXD treatment. Kaempferol treatment reversed the low levels of AMH, estradiol (E2), AFC, superoxide dismutase (SOD), and catalase (CAT), as well as the high levels of follicle-stimulating hormone (FSH), reactive oxygen species (ROS), and malonaldehyde (MDA). The results showed that HSP90 was predicted to have high affinity with kaempferol, and its expression was inhibited by kaempferol, while the expression of NRF2, the target of HSP90, was up-regulated by kaempferol. However, the above effects of kaempferol were reversed by GGA. On the contrary, GDA enhanced the therapeutic effects of kaempferol on AR-DOR mice. Moreover, the treatment of kaempferol resulted in a reduction in the phosphorylation level of heat shock factor 1 (HSF1), the transcription factor associated with HSP90, and an increase in the phosphorylation level of Src, a client protein of HSP90. In summary, kaempferol exerts an antioxidant effect on AR-DOR by inhibiting HSP90 expression to up-regulate NRF2 expression. This study provides a theoretical basis for the clinical application of kaempferol in AR-DOR.

Prediction and verification of the active ingredients and potential targets of Erhuang Quzhi Granules on non-alcoholic fatty liver disease based on network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Erhuang Quzhi Granules (EQG) is a compound composed of 13 traditional Chinese medicines developed by the First Affiliated Hospital of Shihezi University. In clinical practice, EQG has been applied to the treatment of hyperlipidemia and non-alcoholic fatty liver disease (NAFLD), and could significantly improve the serum biochemical indicators of NAFLD patients.

AIM OF THE STUDY

This study aims to explore the bioactive compounds, potential targets, and molecular mechanisms of EQG against NAFLD through network pharmacology, molecular docking, and experimental verification.

MATERIALS AND METHODS

The chemical components of EQG came from the literature and quality standard. Bioactive compounds were screened based on the absorption, distribution, metabolism, and excretion (ADME) feature, and their potential targets were predicted using the substructure-drug-target network-based inference (SDTNBI). The core targets and signaling pathways were obtained through the analysis of protein-protein interaction (PPI), gene ontology (GO) function, and Kyoto encyclopedia of genes and genomes (KEGG) pathway. The results were further confirmed by literature retrieval, molecular docking, and in vivo experiments.

RESULTS

The results of network pharmacology showed 12 active ingredients and 10 core targets for EQG in treating NAFLD. And EQG mainly regulates lipid and atherosclerosis-related pathways to improve NAFLD. The collected literature verified the regulatory effect of the active components of EQG on core targets TP53, PPARG, EGFR, HIF1A, PPARA, and MTOR. Molecular docking results showed that Aloe-Emodin (AE), Emodin, Physcion, and Rhein (RH) had stable binding structures with the core targets HSP90AA1. In vivo experiment showed that AE and RH reduced aspartate transaminase (AST), alanine aminotransferase (ALT), interleukin (IL)-1β, IL-6, IL18, and tumor necrosis factor α (TNF-α) in the serum or liver of NAFLD mice, improved liver lipid deposition and fibrosis, and inhibit gene expression of nuclear factor kappa B (NF-κB), NOD-like receptor thermal protein domain associated protein 3 (NLRP3), IL-1β, TNF-α and protein expression of HSP90, NF-κB and Cleaved caspase-1.

CONCLUSIONS

This study comprehensively revealed the biological compounds, potential targets, and molecular mechanisms of EQG in the treatment of NAFLD, providing a reference basis for the promotion of EQG in the clinic.

Cytosolic Hsp90 Isoform-Specific Functions and Clinical Significance

The heat shock protein 90 (Hsp90) is a molecular chaperone and a key regulator of proteostasis under both physiological and stress conditions. In mammals, there are two cytosolic Hsp90 isoforms: Hsp90α and Hsp90β. These two isoforms are 85% identical and encoded by two different genes. Hsp90β is constitutively expressed and essential for early mouse development, while Hsp90α is stress-inducible and not necessary for survivability. These two isoforms are known to have largely overlapping functions and to interact with a large fraction of the proteome. To what extent there are isoform-specific functions at the protein level has only relatively recently begun to emerge. There are studies indicating that one isoform is more involved in the functionality of a specific tissue or cell type. Moreover, in many diseases, functionally altered cells appear to be more dependent on one particular isoform. This leaves space for designing therapeutic strategies in an isoform-specific way, which may overcome the unfavorable outcome of pan-Hsp90 inhibition encountered in previous clinical trials. For this to succeed, isoform-specific functions must be understood in more detail. In this review, we summarize the available information on isoform-specific functions of mammalian Hsp90 and connect it to possible clinical applications.