Celecoxib-mediated attenuation of non-alcoholic steatohepatitis is potentially relevant to redistributing the expression of adiponectin receptors in rats

Global deletion of COX-2 Attenuates Hepatic Inflammation but Impairs Metabolic Homeostasis in Diet-Induced Obesity

The role of cyclooxygenase-2 (COX-2), a well-known pharmacological target for attenuating inflammation, in regulating obesity and its co-morbidities remains unclear. We sought to determine the role of COX-2 in modulating metabolic inflammation and systemic metabolic homeostasis in obesity. Male wild type (WT) and COX-2 knock-out (KO) mice were fed a chow diet (CD) or a high fat diet (HF, 45% fat) for 13 wk. While the body weight gain did not alter, the visceral adipose tissue (VAT) mass was significantly higher in KO-HF mice compared to WT-HF mice. Plasma triglycerides and total cholesterol levels were higher in KO-HF mice compared to WT-HF mice. Total body fat mass was higher with a concomitant reduction in lean mass in KO-HF mice compared to WT-HF mice. Paradoxically, hepatic steatosis was reduced in KO-HF mice. While liver triglycerides were reduced, the liver cholesterol was increased in KO-HF mice. Bile acids and markers of cholesterol biosynthesis were unaltered between WT-HF and KO-HF groups. The mRNA and/or protein levels of autophagy markers were significantly decreased in KO-HF mice compared to WT-HF mice, indicating that a reduction in autophagy may increase cholesterol levels in these mice. The liver inflammatory markers were significantly increased only in WT mice fed a HF diet but not in KO-HF fed mice compared to their respective controls. VAT showed a reduction in inflammatory markers in spite of an increase in adiposity. These data suggest that despite being effective in attenuating the inflammatory processes, inhibition of COX-2 exerts undesirable consequences on metabolic homeostasis.

Novel thiazolones for the simultaneous modulation of PPARγ, COX-2 and 15-LOX to address metabolic disease-associated portal inflammation

A hybrid pharmacophore model, based on structural motifs previously identified by our team, was employed to generate ligands that simultaneously target COX-2, 15-LOX, and PPARγ in the context of metabolic dysfunction-associated fatty liver disease (MAFLD). Notable COX-2 inhibitory activities (IC50 = 0.065-0.24 μM) were observed relative to celecoxib (IC50 = 0.049 μM). The two most effective 15-LOX inhibitors, 2a and 2b, exhibited 69 % and 57 % of quercetin's action, respectively. Utilizing the rat hemi-diaphragm model to assess in vitro glucose uptake capacity, compounds 2a and 2b demonstrated significant glucose uptake potential in the absence of insulin, surpassing that of pioglitazone. Compound 2a activated PPARγ with an EC50 value of 3.4 μM in a Gal4-hybrid reporter gene assay, indicating partial agonistic action. Interesting binding interactions with targets of interest were identified by molecular docking studies. As well, the expression levels of 20-HETE, Il-1β and TNF-α were decreased in LPS-challenged RAW264.7 macrophages upon treatment with compound 2a. The pharmacokinetic analysis of 2a and assessment of its in vivo efficacy in addressing hepatic impairment in rat models of diabetes and pre-diabetes were carried out. Together, these findings may offer preliminary insights into the potential of these compounds for further refinement in the existing therapeutic arsenals for metabolic diseases.

Yanggan Jiangmei Formula alleviates hepatic inflammation and lipid accumulation in non-alcoholic steatohepatitis by inhibiting the NF-κB/NLRP3 signaling pathway

The role of NF-κB and the NLRP3 inflammasome in the chronic inflammatory microenvironment of non-alcoholic steatohepatitis (NASH) has been posited as crucial. The Yanggan Jiangmei Formula (YGJMF) has shown promise in ameliorating hepatic steatosis in NASH patients, yet its pharmacological mechanisms remain largely unexplored. This study was conducted to investigate the efficacy of YGJMF in NASH and to elucidate its pharmacological underpinnings. To simulate NASH both in vivo and in vitro, high-fat-diet (HFD) rats and HepG2 cells stimulated with free fatty acids (FFAs) were utilized. The severity of liver injury and lipid deposition was assessed using serum indicators, histopathological staining, micro-magnetic resonance imaging (MRI), and the liver-to-muscle signal intensity ratio (SIRL/M). Furthermore, a combination of enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC), immunofluorescence, real-time quantitative polymerase chain reaction (RT-qPCR), and Western blotting analyses was employed to investigate the NF-κB/NLRP3 signaling pathway and associated cytokine levels. The results from liver pathology, MRI assessments, and biochemical tests in rat models demonstrated YGJMF's significant effectiveness in reducing liver damage and lipid accumulation. Additionally, YGJMF markedly reduced hepatocyte inflammation by downregulating inflammatory cytokines in both liver tissue and serum. Furthermore, YGJMF was found to disrupt NF-κB activation, consequently inhibiting the assembly of the NLRP3 inflammasome in both the in vitro and in vivo models. The preliminary findings of this study suggest that YGJMF may alleviate hepatic steatosis and inhibit the NF-κB/NLRP3 signaling pathway, thereby exerting anti-inflammatory effects in NASH.

Downregulation of 15-PGDH enhances MASH-HCC development via fatty acid-induced T-cell exhaustion

Background & Aims

Hepatocellular carcinoma (HCC) mainly develops from chronic hepatitis. Metabolic dysfunction-associated steatohepatitis (MASH) has gradually become the main pathogenic factor for HCC given the rising incidence of obesity and metabolic diseases. 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) degrades prostaglandin 2 (PGE2), which is known to exacerbate inflammatory responses. However, the role of PGE2 accumulation caused by 15-PGDH downregulation in the development of MASH-HCC has not been determined.

Methods

We utilised the steric animal model to establish a MASH-HCC model using wild-type and 15-Pgdh+/- mice to assess the significance of PGE2 accumulation in the development of MASH-HCC. Additionally, we analysed clinical samples obtained from patients with MASH-HCC.

Results

PGE2 accumulation in the tumour microenvironment induced the production of reactive oxygen species in macrophages and the expression of cell growth-related genes and antiapoptotic genes. Conversely, the downregulation of fatty acid metabolism in the background liver promoted lipid accumulation in the tumour microenvironment, causing a decrease in mitochondrial membrane potential and CD8+ T-cell exhaustion, which led to enhanced development of MASH-HCC.

Conclusions

15-PGDH downregulation inactivates immune surveillance by promoting the proliferation of exhausted effector T cells, which enhances hepatocyte survival and proliferation and leads to the development of MASH-HCC.

Impact and implications

The suppression of PGE2-related inflammation and subsequent lipid accumulation leads to a reduction in the severity of MASH and inhibition of subsequent progression toward MASH-HCC.

Lipidomics in pathogenesis, progression and treatment of nonalcoholic steatohepatitis (NASH): Recent advances

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease affecting up to 30% of the general adult population. NAFLD encompasses a histological spectrum ranging from pure steatosis to non-alcoholic steatohepatitis (NASH). NASH can progress to cirrhosis and is becoming the most common indication for liver transplantation, as a result of increasing disease prevalence and of the absence of approved treatments. Lipidomic readouts of liver blood and urine samples from experimental models and from NASH patients disclosed an abnormal lipid composition and metabolism. Collectively, these changes impair organelle function and promote cell damage, necro-inflammation and fibrosis, a condition termed lipotoxicity. We will discuss the lipid species and metabolic pathways leading to NASH development and progression to cirrhosis, as well as and those species that can contribute to inflammation resolution and fibrosis regression. We will also focus on emerging lipid-based therapeutic opportunities, including specialized proresolving lipid molecules and macrovesicles contributing to cell-to-cell communication and NASH pathophysiology.

Interdisciplinary advances reshape the delivery tools for effective NASH treatment

BACKGROUND

Nonalcoholic steatohepatitis (NASH), a severe systemic and inflammatory subtype of nonalcoholic fatty liver disease, eventually develops into cirrhosis and hepatocellular carcinoma with few options for effective treatment. Currently potent small molecules identified in preclinical studies are confronted with adverse effects and long-term ineffectiveness in clinical trials. Nevertheless, highly specific delivery tools designed from interdisciplinary concepts may address the significant challenges by either effectively increasing the concentrations of drugs in target cell types, or selectively manipulating the gene expression in liver to resolve NASH.

SCOPE OF REVIEW

We focus on dissecting the detailed principles of the latest interdisciplinary advances and concepts that direct the design of future delivery tools to enhance the efficacy. Recent advances have indicated that cell and organelle-specific vehicles, non-coding RNA research (e.g. saRNA, hybrid miRNA) improve the specificity, while small extracellular vesicles and coacervates increase the cellular uptake of therapeutics. Moreover, strategies based on interdisciplinary advances drastically elevate drug loading capacity and delivery efficiency and ameliorate NASH and other liver diseases.

MAJOR CONCLUSIONS

The latest concepts and advances in chemistry, biochemistry and machine learning technology provide the framework and strategies for the design of more effective tools to treat NASH, other pivotal liver diseases and metabolic disorders.