Hepatoprotective effects of paeonol by suppressing hepatic stellate cell activation via inhibition of SMAD2/3 and STAT3 pathways

Hepatic stellate cell (HSC) activation is a key event in extracellular matrix accumulation, causing hepatic fibrosis. Therefore, identifying chemicals that inhibit HSC activation is an important therapeutic strategy for hepatic fibrosis. The aim of this study was to investigate the therapeutic effects of paeonol on HSC activation. In LX-2 cells, paeonol inhibited the expression of collagen and decreased the expression of HSC activation markers. In mice with thioacetamide-induced liver fibrosis, paeonol treatment decreased the serum levels of aspartate aminotransferase and alanine transaminase and mRNA expression of α-smooth muscle actin, platelet-derived growth factor-β, and connective-tissue growth factor. Investigation of the underlying molecular mechanism of paeonol showed that paeonol inhibits the SMAD2/3 and STAT3 signaling pathways that are important for HSC activation. On the basis of these results, paeonol should be investigated and developed further for hepatic fibrosis treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01440-9.

Deficiency of HtrA3 Attenuates Bleomycin-Induced Pulmonary Fibrosis Via TGF-β1/Smad Signaling Pathway

PURPOSE

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease characterized by excessive extracellular matrix deposition. No effective treatments are currently available for IPF. High-temperature requirement A3 (HtrA3) suppresses tumor development by antagonizing transforming growth factor β (TGF-β) signaling; however, little is known about the role of HtrA3 in IPF. This study investigated the role of HtrA3 in IPF and underlying mechanisms.

METHODS

Lung tissues were collected from patients with IPF and mice with bleomycin (BLM)-induced pulmonary fibrosis, and HtrA3 expression was measured in tissue samples. Then, HtrA3 gene knockout mice were treated with BLM to induce pulmonary fibrosis and explore the effects and underlying mechanism of HtrA3 on pulmonary fibrosis.

RESULTS

HtrA3 was up-regulated in the lung tissues of patients with IPF and the pulmonary fibrotic mouse model compared to corresponding control groups. HtrA3 knockout decreased pulmonary fibrosis-related protein expression, alleviated the symptoms of pulmonary fibrosis, and inhibited epithelial-mesenchymal transition (EMT) in BLM-induced lung tissue compared with BLM-induced wild-type mice. The TGF-β1/Smad signaling pathway was activated in fibrotic lung tissue, whereas HtrA3 knockout inhibited this pathway.

CONCLUSION

The expression level of HtrA3 is increased in fibrotic lungs. HtrA3 knockout alleviates the symptoms of pulmonary fibrosis probably via the TGF-β1/Smad signaling pathway. Therefore, HtrA3 inhibition is a potential therapeutic target for pulmonary fibrosis.

Pathophysiology of mesangial expansion in diabetic nephropathy: mesangial structure, glomerular biomechanics, and biochemical signaling and regulation

Diabetic nephropathy, a kidney complication arising from diabetes, is the leading cause of death in diabetic patients. Unabated, the growing epidemic of diabetes is increasing instances of diabetic nephropathy. Although the main causes of diabetic nephropathy have been determined, the mechanisms of their combined effects on cellular and tissue function are not fully established. One of many damages of diabetic nephropathy is the development of fibrosis within the kidneys, termed mesangial expansion. Mesangial expansion is an important structural lesion that is characterized by the aberrant proliferation of mesangial cells and excess production of matrix proteins. Mesangial expansion is involved in the progression of kidney failure in diabetic nephropathy, yet its causes and mechanism of impact on kidney function are not well defined. Here, we review the literature on the causes of mesangial expansion and its impacts on cell and tissue function. We highlight the gaps that still remain and the potential areas where bioengineering studies can bring insight to mesangial expansion in diabetic nephropathy.

Design, synthesis and discovery of 2(1H)-quinolone derivatives for the treatment of pulmonary fibrosis through inhibition of TGF-β/smad dependent and independent pathway

Idiopathic pulmonary fibrosis (IPF) is a progressive, life-threatening and interstitial lung disease with the median survival of only 3-5 years. However, due to the unclear etiology and problems in accurate diagnosis, up to now only two drugs were approved by FDA for the treatment of IPF and their outcome responses are limited. Numerous studies have shown that TGF-β is the most important cytokine in the development of pulmonary fibrosis and plays a role through its downstream signaling molecule TGF-binding receptor Smads protein. In this paper, compounds bearing 2(1H)-quinolone scaffold were designed and their anti-fibrosis effects were evaluated. Of these compounds, 20f was identified as the most active one and could inhibit TGF-β-induced collagen deposition of NRK-49F cells and mouse fibroblasts migration with comparable activity and lower cytotoxicity than nintedanib in vitro. Further mechanism studies indicated that 20f reduced the expression of fibrogenic phenotypic protein α-SMA and collagen Ⅰ by inhibiting the TGF-β/Smad dependent pathways and ERK1/2 and p38 pathways. Moreover, compared with the nintedanib, 20f (100 mg/kg/day, p.o) more effectively alleviated collagen deposition in lung tissue and delayed the destruction of lung tissue structure both in bleomycin-induced prevention and treatment mice pulmonary fibrosis models. The immunohistochemical experiments further showed that 20f could block the expression level of phosphorylated Smad3 in the lung tissue cells, which resulted in its anti-fibrosis effects in vivo. In addition, 20f demonstrated good bioavailability (F = 41.55% vs 12%, compare with nintedanib) and an appropriate elimination half-life (T_1/2 = 3.5 h), suggesting that 20f may be a potential drug candidate for the treatment of pulmonary fibrosis.

Hyperbranched lipoid-based lipid nanoparticles for bidirectional regulation of collagen accumulation in liver fibrosis

Liver fibrosis leads to over one million deaths annually worldwide. Hepatic stellate cells (HSCs) have been identified as the main executors of liver fibrosis. Unfortunately, no drug has yet been approved for clinical use against liver fibrosis, largely because the tested drugs have been unable to access HSCs and efficiently remove the collagen accumulation involved in fibrogenesis. Here, we designed an efficient HSC-targeting lipid delivery system that carried dual siRNAs intended to both inhibit collagen synthesis and promote collagen degradation, with the goal of realizing enhanced anti-liver fibrosis by bidirectional regulation of collagen accumulation. The delivery system was constructed by using amphiphilic cationic hyperbranched lipoids (C₁₅-PA) for siRNA complexation and helper lipoids (cholesterol-polyethylene glycol-vitamin A, Chol-PEG-VA) for HSCs targeting. The generated vitamin A-decorated and hyperbranched lipoid-based lipid nanoparticles (VLNPs) showed excellent gene-binding ability and transfection efficiency, and enhanced the delivery of siRNAs to HSCs. Fibrotic mice treated with dual siRNA-loaded VLNPs showed a great reduction in the collagen accumulation seen in this model; the enhanced effect of bidirectional regulation reduced the collagen accumulation level in treated mice to almost that seen in normal mice. There was no notable sign of toxicity or tissue inflammation in mice exposed to repeated intravenous administration of the dual siRNA-loaded VLNPs. In conclusion, our results indicate that biocompatible VLNPs designed to exploit precise targeting and an effective bidirectional regulation strategy hold promise for treating liver fibrosis.

Synthesis and discovery of new compounds bearing coumarin scaffold for the treatment of pulmonary fibrosis

Idiopathic pulmonary fibrosis, characterized by excess accumulation of extracellular matrix, involved in many chronic diseases or injuries, threatens human health greatly. We have reported a series of compounds bearing coumarin scaffold which potently inhibited TGF-β-induced total collagen accumulation in NRK-49F cell line and migration of macrophages. Compound 9d also suppressed the TGF-β-induced protein expression of COL1A1, α-SMA, and p-Smad3 in vitro. Meanwhile, 9d at a dose of 100 mg/kg/day through oral administrations for 4 weeks effectively alleviated infiltration of inflammatory cells in lung tissue and fibrotic degree in bleomycin-induced pulmonary fibrosis model, which may related to its inhibition of TGF-β/Smad3 pathway and anti-inflammation efficacy. In addition, 9d demonstrated decent bioavailability (F = 39.88%) and suitable eliminated half-life time (T_1/2 = 13.09 h), suggesting that 9d could be a potential drug candidate for the treatment of fibrotic diseases.

TGF-β1- and CCN2-Stimulated Sirius Red Assay for Collagen Accumulation in Cultured Cells

A simple method for the determination of relative levels of insoluble collagen accumulation in fibroblast cultures is presented. Confluent cell cultures are provided with sodium ascorbate which is then permissive for collagen deposition. At intervals, cultures are fixed and stained successively with sirius red and then crystal Violet to, respectively, assess for relative changes in collagen accumulation in response to factors such as TGF-β1 or matricellular CCN2 and changes in DNA content as an index of changes in cell density.