Emerging novel targets for nonalcoholic fatty liver disease treatment: Evidence from recent basic studies

Advances in nanotechnology for the diagnosis and management of metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) has a high global incidence and associated with increased lipid accumulation in hepatocytes, elevated hepatic enzyme levels, liver fibrosis, and hepatic carcinoma. Despite decades of research and significant advancements, the treatment of MASLD still faces formidable challenges. Nanoprobes for diagnostics and nanomedicine for targeted drug delivery to the liver present promising options for MASLD diagnosis and treatment, enhancing both imaging contrast and bioavailability. Here, we review recent advances in nanotechnology applied to MASLD diagnosis and treatment, specifically focusing on drug delivery systems targeting hepatocytes, hepatic stellate cells, Kupffer cells, and liver sinusoidal endothelial cells. This review aims to provide an overview of nanomedicine's potential in early MASLD diagnosis and therapeutic interventions, addressing related complications.

Impaired mitochondrial degradation of CHCHD2 promotes metabolic dysfunction-associated steatohepatitis-related hepatocellular carcinoma by upregulating VEGFA

Metabolic dysfunction-associated steatohepatitis (MASH) is the fastest-growing cause of liver cancer. The liver microenvironment of patients with MASH supports the development of hepatocellular carcinoma (HCC). Coiled-coil-helix-coiled-coil-helix domain-containing 2 (CHCHD2), which is located in both the mitochondria and nucleus, is increased in MASH liver. Its role in the development of MASH-HCC remain unknown. In this study, we found CHCHD2 protein levels were elevated in both tumor and para-tumor tissues of patients with MASH-HCC and diethylnitrosamine- and high-fat diet-induced MASH-HCC mice. Chchd2-knockout mice were generated. CHCHD2 was overexpressed in hepatocytes using AAV with TBG promoter. Chchd2 knockout inhibited the progression of MASH-HCC in mice. CHCHD2 protein-targeted ChIP-sequencing data revealed that CHCHD2 target genes encoding secretory proteins were enriched in cancer pathways. Among these genes, vascular endothelial growth factor A (VEGFA) level increased in CHCHD2-overexpressing livers and hepatocytes. Chchd2 knockdown reduced palmitate-induced VEGFA expression. Palmitate-treated hepatocyte increased the angiogenic activity of endothelial cells in a paracrine manner, and this was suppressed by Chchd2 knockdown in hepatocytes. CHCHD2-overexpressing hepatocytes promoted the angiogenic activity of endothelial cells. We futher employed an orthotopic murine model of HCC to demonstrate that elevated CHCHD2 protein levels in para-tumor tissues support HCC growth. In addition, we found that the degradation of CHCHD2 was primarily mediated by mitochondrial protease ClpXP, which was repressed in the MASH liver. In conclusion, the mitochondrial degradation of CHCHD2 is impaired in MASH, and elevated CHCHD2 levels in hepatocytes promote VEGFA transcription and support the growth of HCC.

(+)-Lipoic acid reduces mitochondrial unfolded protein response and attenuates oxidative stress and aging in an in vitro model of non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a liver disorder characterized by the ac-cumulation of fat in hepatocytes without alcohol consumption. Mitochondrial dysfunction and endoplasmic reticulum (ER) stress play significant roles in NAFLD pathogenesis. The unfolded protein response in mitochondria (UPRmt) is an adaptive mechanism that aims to restore mitochondrial protein homeostasis and mitigate cellular stress. This study aimed to investigate the effects of ( +)-Lipoic acid (ALA) on UPRmt, inflammation, and oxidative stress in an in vitro model of NAFLD using HepG2 cells treated with palmitic acid and oleic acid to induce steatosis.

RESULTS

Treatment with palmitic and oleic acids increased UPRmt-related proteins HSP90 and HSP60 (heat shock protein), and decreased CLPP (caseinolytic protease P), indicating ER stress activation. ALA treatment at 1 μM and 5 μM restored UPRmt-related protein levels. PA:OA (palmitic acid:oleic acid)-induced ER stress markers IRE1α (Inositol requiring enzyme-1), CHOP (C/EBP Homologous Protein), BIP (Binding Immunoglobulin Protein), and BAX (Bcl-2-associated X protein) were significantly reduced by ALA treatment. ALA also enhanced ER-mediated protein glycosylation and reduced oxidative stress, as evidenced by decreased GPX1 (Glutathione peroxidase 1), GSTP1 (glutathione S-transferase pi 1), and GSR (glutathione-disulfide reductase) expression and increased GSH (Glutathione) levels, and improved cellular senescence as shown by the markers β-galactosidase, γH2Ax and Klotho-beta.

CONCLUSIONS

In conclusion, ALA ameliorated ER stress, oxidative stress, and inflammation in HepG2 cells treated with palmitic and oleic acids, potentially offering therapeutic benefits for NAFLD providing a possible biochemical mechanism underlying ALA beneficial effects.

Targeting ferroptosis with natural products in liver injury: new insights from molecular mechanisms to targeted therapies

BACKGROUND

Ferroptosis is a brand-new type of controlled cell death that is distinguished by its reliance on iron and the production of lipid peroxidation. The role of ferroptosis in damaging liver disorders has attracted a lot of attention in recent years. One effective strategy to reduce liver damage is to target ferroptosis.

PURPOSE

The purpose of this review is to clarify the connection between ferroptosis and liver damage and to look into the potential contribution of natural products to the clinical management of liver damage and the discovery of novel medications.

METHODS

To study the methods by which natural products operate on ferroptosis to cure liver damage and their main signaling pathways, we searched databases from the time of initial publication to August 2023 in PubMed, EMBASE, Web of Science, Ovid, ScienceDirect, and China National Knowledge Infrastructure. The liver illness that each natural product treats is categorized and summarized. It's interesting to note that several natural compounds, such Artemether, Fucoidan sulfate, Curcumin, etc., have the benefit of having many targets and multiple pathways of action.

RESULTS

We saw that in human samples or animal models of liver injury, ferroptosis indicators were activated, lipid peroxidation levels were elevated, and iron inhibitors had the ability to reduce liver damage. Liver damage can be treated with natural products by regulating ferroptosis. This is mostly accomplished through the modulation of Nrf2-related pathways (e.g., Conclusions and Astaxanthin), biological enzymes like GPX4 and the SIRT family (e.g., Chrysophanol and Decursin), and transcription factors like P53 (e.g., Artemether and Zeaxanthin).

CONCLUSIONS

This review proposes a promising path for the therapeutic therapy of liver damage by providing a theoretical foundation for the management of ferroptosis utilizing natural ingredients.

Ginsenoside Rh2 promotes hepatic stellate cell ferroptosis and inactivation via regulation of IRF1-inhibited SLC7A11

BACKGROUND

Sustained liver fibrosis may lead to cirrhosis. Activated hepatic stellate cells (HSCs) are crucial for liver fibrosis development. Ferroptosis, a newly iron-dependent regulated cell death, has been demonstrated to be involved in HSC inactivation.

PURPOSE

Ginsenoside Rh2 (GRh2), a natural bioactive product derived from ginseng, has been shown to promote HSC inactivation. However, the effect of GRh2 on HSC ferroptosis remains unclear.

METHODS

We explored the effects of GRh2 on liver fibrosis in vivo and in vitro. RNA-sequence analysis was performed in HSCs after GRh2 treatment. The crosstalk between ferroptotic HSCs and macrophages was also explored.

RESULTS

GRh2 alleviated liver fibrosis in vivo. In vitro, GRh2 reduced HSC proliferation and activation via ferroptosis, with increased intracellular iron, reactive oxygen species, malondialdehyde and glutathione depletion. The expression of SLC7A11, a negative regulator of ferroptosis, was obviously reduced by GRh2. Interestingly, interferon regulatory factor 1 (IRF1), a transcription factor, was predicted to bind the promoter region of SCL7A11. The interaction between IRF1 and SCL7A11 was further confirmed by the results of chromatin immunoprecipitation and luciferase reporter assays. Furthermore, loss of IRF1 led to an increase in SCL7A11, which contributed to the suppression of HSC ferroptosis and the enhancement of HSC activation in GRh2-treated HSCs. Further studies revealed that GRh2-induced HSC ferroptosis contributed to the inhibition of macrophage recruitment via regulation of inflammation-related genes. Moreover, GRh2 caused a reduction in liver inflammation in vivo.

CONCLUSION

Collectively, GRh2 up-regulates IRF1 expression, resulting in the suppression of SLC7A11, which contributes to HSC ferroptosis and inactivation. GRh2 ameliorates liver fibrosis through enhancing HSC ferroptosis and inhibiting liver inflammation. GRh2 may be a promising drug for treating liver fibrosis.