Efficient hepatic differentiation and regeneration potential under xeno-free conditions using mass-producible amnion-derived mesenchymal stem cells

BACKGROUND

Amnion-derived mesenchymal stem cells (AM-MSCs) are an attractive source of stem cell therapy for patients with irreversible liver disease. However, there are obstacles to their use due to low efficiency and xeno-contamination for hepatic differentiation.

METHODS

We established an efficient protocol for differentiating AM-MSCs into hepatic progenitor cells (HPCs) by analyzing transcriptome-sequencing data. Furthermore, to generate the xeno-free conditioned differentiation protocol, we replaced fetal bovine serum (FBS) with polyvinyl alcohol (PVA). We investigated the hepatocyte functions with the expression of mRNA and protein, secretion of albumin, and activity of CYP3A4. Finally, to test the transplantable potential of HPCs, we transferred AM-MSCs along with hepatic progenitors after differentiated days 11, 12, and 13 based on the expression of hepatocyte-related genes and mitochondrial function. Further, we established a mouse model of acute liver failure using a thioacetamide (TAA) and cyclophosphamide monohydrate (CTX) and transplanted AM-HPCs in the mouse model through splenic injection.

RESULTS

We analyzed gene expression from RNA sequencing data in AM-MSCs and detected downregulation of hepatic development-associated genes including GATA6, KIT, AFP, c-MET, FGF2, EGF, and c-JUN, and upregulation of GSK3. Based on this result, we established an efficient hepatic differentiation protocol using the GSK3 inhibitor, CHIR99021. Replacing FBS with PVA resulted in improved differentiation ability, such as upregulation of hepatic maturation markers. The differentiated hepatocyte-like cells (HLCs) not only synthesized and secreted albumin, but also metabolized drugs by the CYP3A4 enzyme. The best time for translation of AM-HPCs was 12 days from the start of differentiation. When the AM-HPCs were transplanted into the liver failure mouse model, they settled in the damaged livers and differentiated into hepatocytes.

CONCLUSION

This study offers an efficient and xeno-free conditioned hepatic differentiation protocol and shows that AM-HPCs could be used as transplantable therapeutic materials. Thus, we suggest that AM-MSC-derived HPCs are promising cells for treating liver disease.

[Mechanism of Astragaloside prevents cholestatic liver fibrosis through inhibition of Notch signaling activation]

Objective: The Notch signaling pathway is closely related to biliary fibrosis. Previous studies have shown that Astragaloside (AS) can prevent the progression of cholestatic liver fibrosis. The purpose of this study is to observe the effect of AS on the regulation of Notch signaling pathway in biliary fibrosis. Methods: Cholestatic liver fibrosis was established by common bile duct ligation (BDL) in rats. Two weeks after BDL, the rats were randomly divided into a model group (i.e., BDL), an Astragalosides group (AS), and a sorafenib (SORA) positive control group and treated for 3 weeks. Bile duct proliferation and liver fibrosis were determined by tissue staining. Protein and gene expression were determined by immunostaining, immunoblotting and RT-PCR, respectively. Activation of the Notch signaling pathway was evaluated by analyzing expressions of Notch-1, -2, -3, -4, Jagged (JAG)1, Delta like (DLL)-1, -3, -4, Hes1, Numb and RBP-Jκ. Statistical analysis of variance analysis, q test, P < 0.05 showed that the difference was statistically significant. Results: (1) AS significantly reduced the deposition of collagen and the Hyp content of liver tissue (500.15 ± 86.10 vs. 625.72 ± 105.62, P = 0.031), and inhibited the activation of hepatic stellate cells. (2) AS significantly decreased the protein and mRNA expressions of transforming growth factor (TGF)-β1 (1.02±0.15 vs. 1.89±0.36, P = 0.007; 1.17±0.18 vs. 1.68±0.29, P = 0.013, respectively) and α-smooth muscle actin (α-SMA, 0.41±0.11 vs. 0.72±0.16, P = 0.003; 1.71±0.57 vs. 2.68±0.46, P = 0.008, respectively) compared with BDL group. In contrast, AS significantly enhanced expression of the Smad 7 protein compared with the BDL group (0.72±0.008 vs. 0.33±0.001, P = 0.005). AS also reduced biliary epithelial cell proliferation. AS reduced the mRNA levels of CK7, CK8 and CK18 (1.31±0.39 vs. 2.63±0.82, P = 0.009; 0.71±0.09 vs. 0.87±0.08, P = 0.031; 2.56±0.32 vs. 3.41±0.39, P = 0.010, respectively) and reduced the positive areas of CK19 and OV6 (62 337.17±21 873.38 vs. 22 5472.67±26 933.63, P = 0.000; 92 237.43±15 894.11 vs. 171 298.13±61 761.37, P = 0.000, respectively). (3) The mRNA expression of Notch-2, -3, -4 and JAG1 were significantly reduced in the AS group compared to the BDL group (1.07±0.19 vs. 1.51±0.28, P = 0.044; 0.99±0.24 vs. 1.18±0.10, P = 0.043; 1.36±0.42 vs. 3.40±0.44, P = 0.048; 2.62±0.43 vs. 3.73±0.83, P = 0.046, respectively). In contrast, the mRNA level of Numb was clearly enhanced after AS treatment (0.90±0.05 vs. 0.75±0.11, P = 0.019). In addition, consistent with the mRNA levels, the protein expressions of Notch-2, -3, -4 and JAG1 were reduced significantly (1.27±0.18 vs. 1.71±0.26, P = 0.004; 0.99±0.11 vs. 4.38±0.60, P = 0.001; 1.76±0.32 vs. 4.01±0.74, P = 0.002; 1.62±0.33 vs. 2.74±0.63, P = 0.002) and the Numb protein level was increased significantly (1.50±0.15 vs. 0.85±0.11, P = 0.001) in AS group compared with BDL group. Conclusion: AS may prevent cholestatic liver fibrosis via inhibition of the Notch signaling pathway, thereby inhibiting the abnormal proliferation of biliary epithelial cells. Results indicate that AS may be a potential treatment for cholestatic liver disease.

Astragaloside prevents BDL-induced liver fibrosis through inhibition of notch signaling activation

ETHNOPHARMACOLOGICAL RELEVANCE

Huangqi decoction was first described in Prescriptions of the Bureau of Taiping People׳s Welfare Pharmacy in the Song Dynasty (AD1078). It consists of Radix Astragali (Astragalus membranceus (Fisch.) Bge. Root, Huangqi) and Radix Glycyrrhizae (Glycyrrhiza uralensis Fisch., root and rhizome, Gancao), and it is an effective recipe that is usually used to treat consumptive disease and chronic liver diseases. Astragaloside (AS) is a main component of Radix Astragali had an effect similar to the Huangqi decoction on hepatic fibrosis.

AIM OF THE STUDY

Cholestasis is associated with a number of chronic liver diseases and Notch signaling has been demonstrated to be involved in ductular reaction. Previous studies have shown that AS can prevent the progression of cholestatic liver fibrosis, however, whether AS affects the Notch signaling pathway is unclear.

MATERIALS AND METHODS

Cholestatic liver fibrosis was established by common bile duct ligation (BDL) in rats. At first weekend, the rats were randomly divided into a model group (BDL), an AS group, and a Sorafenib positive control group (SORA) and treated for 3 weeks. Bile duct proliferation and liver fibrosis were determined by tissue staining. Activation of the Notch signaling pathway was evaluated by analyzing expressions of Notch-1, -2, -3, -4, Jagged 1 (JAG1), Delta-like (DLL)-1, -3, -4, Hes1, Numb and RBP-Jκ. Activation of the Wnt signaling pathway was evaluated by analyzing expressions of Wnt-4, -5a, -5b, Frizzled (Fzd)-2, -3, -6 and β-catenin.

RESULTS

(1) Compared with the BDL group, AS significantly reduced the deposition of collagen and the Hyp content of liver tissue and inhibited the activation of HSCs. In addition, AS significantly decreased the protein and mRNA expressions of TGF-β1 and α-SMA. In contrast, AS significantly enhanced expression of the Smad 7 protein. AS also reduced biliary epithelial cell proliferation, and reduced the mRNA and protein expressions of CK7, CK8, CK18, CK19, OV6, Sox9 and EpCAM. (2) The mRNA and protein expressions of Notch-2, -3, -4 and JAG1 were significantly reduced in the AS compared to the BDL group. In contrast, the mRNA and protein level of Numb was clearly enhanced after AS treatment.

CONCLUSION

AS may prevent biliary liver fibrosis via inhibition of the Notch signaling pathway, thereby inhibiting the abnormal proliferation of biliary epithelial cells. Results indicate that AS may be a potential therapeutic drug for cholestatic liver disease.