Endogenous alpha-calcitonin gene-related peptide mitigates liver fibrosis in chronic hepatitis induced by repeated administration of concanavalin A

Gomisin D alleviates liver fibrosis through targeting PDGFRβ in hepatic stellate cells

Platelet-derived growth factor receptor β (PDGFRβ) plays an important role in hepatic fibrosis and is closely associated with hepatic stellate cells (HSCs) activation. Previously, by modeling PDGFRβ affinity chromatography, we found that gomisin D can target PDGFRβ. However, whether gomisin D has anti-fibrosis effects through targeting PDGFRβ remained unclear. In this study, the effect of gomisin D on hepatic fibrosis was evaluated in vivo and vitro. HSC cell lines and primary HSC were cultured and functionally we found that gomisin D promotes HSC apoptosis, inhibits HSCs activation and proliferation. A male BALB/c mouse liver fibrosis model was established to comfirm gomisin D (especially in 50 mg/kg) could improve liver fibrosis by inhibiting HSCs activation. In addition, gomisin D had a good binding ability with PDGFRβ (KD = 3.3e^-5 M). Mechanically, gomisin D regulated PDGF-BB/PDGFRβ signaling pathway by targeting PDGFRβ, further more inhibited HSC activation, subsequently inhibited inflammatory factors, ultimately improved CCl₄-induced liver fibrosis. Overall, gomisin D could inhibit HSC proliferation and activation, promote HSC apoptosis, and alleviate CCl₄-induced hepatic fibrosis by targeting PDGFRβ and regulating PDGF-BB/PDGFRβ signaling pathway. This study provides a new drug for anti-liver firbosis therapy, and elucidates the deeper mechanism of gomisin D against HSCs activation by targeting PDGFRβ.

Peptide mediated therapy in fibrosis: Mechanisms, advances and prospects

Fibrosis, a disease characterized by an excess accumulation of extracellular matrix components, could lead to organ failure and death, and is to blame for up to 45 % of all fatalities in developed nations. These disorders all share the common trait of an unchecked and increasing accumulation of fibrotic tissue in the affected organs, which leads to their malfunction and eventual failure, even if their underlying causes are highly diverse and, in some cases, remain unclear. Numerous studies have identified activated myofibroblasts as the common cellular elements ultimately responsible for the replacement of normal tissues with nonfunctional fibrotic tissue. The transforming growth factor-β pathway, for instance, plays a significant role in practically all kinds of fibrosis. However, there is no specific drug for the treatment of fibrosis, several medications with anti-hepatic fibrosis properties are still in the research and development stages. Peptide, which refers to a substance consisting of 2-50 amino acids, is characterized by structural diversity, low toxicity, biological activities, easy absorption, specific targeting, few side effects, and has been proven to be effective in anti-fibrosis. Here, we summarized various anti-fibrosis peptides in fibrosis including the liver, lungs, kidneys, and other organs. This review will provide a new insight into peptide mediated anti-fibrosis and is helpful to creation of antifibrotic medications.

Treated with interferon and the gene polymorphism of CGRP and its receptor

OBJECTIVE

This case-control study aims to investigate the relationship of polymorphisms of four gene loci (CGRP rs155209 and rs3781719, RAMP1 rs3754701 and rs7590387) with the prognosis of interferon therapy for chronic hepatitis B (CHB).

MATERIALS AND METHODS

A total of 317 CHB patients receiving interferon alone for the first time were recruited in northern China, and peripheral blood samples were obtained. The single-nucleotide polymorphisms (SNPs) in rs155209, rs3781719, rs3754701, and rs7590387 were genotyped using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). Univariate and multivariate logistic regression methods were employed to assess the correlation between CHB prognosis treated with interferon and polymorphisms of these gene loci.

RESULTS

The study clearly demonstrated the relevance of polymorphisms of rs155209, rs3781719, rs3754701, and rs7590387 with DNA response and ALT response after interferon treatment. CHB patients with CGRP rs155209C had a lower risk of developing DNA response (CT vs. TT: OR = 0.159, 95% CI = 0.086-0.294, P_adj < 0.001; CC vs. TT: OR = 0.131, 95% CI = 0.059-0.288, P_adj < 0.001), as well as a lower risk of developing ALT response (CT vs. TT: OR = 0.530, 95% CI = 0.323-0.869, P_adj < 0.05). Moreover, CHB patients with RAMP1 rs3754701T allele were more prone to develop DNA response (AT vs. AA: OR = 2.061, 95% CI = 1.237-3.435, P_adj < 0.05; TT vs. AA: OR = 5.676, 95% CI =1.247-25.837, P_adj < 0.05), and they also more likely to develop ALT response (AT vs. AA: OR = 1.766, 95% CI = 1.098-2.840, P_adj < 0.05). We did not find a significant association between CGRP rs3781719 or RAMP1 rs7590387 and DNA response or ALT response.

CONCLUSION

This study revealed that CGRP rs155209 and RAMP1 rs3754701 polymorphisms, but not CGRP rs3781719 and RAMP1 rs7590387, were correlated with interferon therapy prognosis for CHB in Han Chinese population, and RAMP1 rs3754701T was a protective factor for ALT response and DNA response, but CGRP rs155209C carriers were less prone to DNA and ALT responses.

Knockout of α-calcitonin gene-related peptide attenuates cholestatic liver injury by differentially regulating cellular senescence of hepatic stellate cells and cholangiocytes

α-Calcitonin gene-related peptide (α-CGRP) is a 37-amino acid neuropeptide involved in several pathophysiological processes. α-CGRP is involved in the regulation of cholangiocyte proliferation during cholestasis. In this study, we aimed to evaluate if α-CGRP regulates bile duct ligation (BDL)-induced liver fibrosis by using a α-CGRP knockout (α-CGRP^-/-) mouse model. α-CGRP^-/- and wild-type (WT) mice were subjected to sham surgery or BDL for 7 days. Then, liver fibrosis and cellular senescence as well as the expression of kinase such as p38 and C-Jun N-terminal protein kinase (JNK) in mitogen-activated protein kinases (MAPK) signaling pathway were evaluated in total liver, together with measurement of cellular senescence in cholangiocytes or hepatic stellate cells (HSCs). There was enhanced hepatic expression of Calca (coding α-CGRP) and the CGRP receptor components (CRLR, RAMP-1 and RCP) in BDL and in both WT α-CGRP^-/- and BDL α-CGRP^-/- mice, respectively. Moreover, there was increased CGRP serum levels and hepatic mRNA expression of CALCA and CGRP receptor components in late-stage PSC samples compared to healthy control samples. Depletion of α-CGRP reduced liver injury and fibrosis in BDL mice that was associated with enhanced cellular senescence of hepatic stellate cells and reduced senescence of cholangiocytes as well as decreased activation of p38 and JNK MAPK signaling pathway. Cholangiocyte supernatant from BDL α-CGRP^-/- mice inhibited the activation and increased cellular senescence of cultured human HSCs (HHSCs) compared to HHSCs stimulated with BDL cholangiocyte supernatant. Taken together, endogenous α-CGRP promoted BDL-induced cholestatic liver fibrosis through differential changes in senescence of HSCs and cholangiocytes and activation of p38 and JNK signaling. Modulation of α-CGRP/CGRP receptor signaling may be key for the management of biliary senescence and liver fibrosis in cholangiopathies.

Placental extract ameliorates non-alcoholic steatohepatitis (NASH) by exerting protective effects on endothelial cells

Non-alcoholic steatohepatitis (NASH) is a severe form of fatty liver disease that is defined by the presence of inflammation and fibrosis, ultimately leading to cirrhosis and hepatocellular carcinoma. Treatment with human placental extract (HPE) reportedly ameliorates the hepatic injury. We evaluated the effect of HPE treatment in a mouse model of NASH. In the methione- and choline-deficient (MCD) diet-induced liver injury model, fibrosis started from regions adjacent to the sinusoids. We administered the MCD diet with high-salt loading (8% NaCl in the drinking water) to mice deficient in the vasoprotective molecule RAMP2 for 5 weeks, with or without HPE. In both the HPE and control groups, fibrosis was seen in regions adjacent to the sinusoids, but the fibrosis was less pronounced in the HPE-treated mice. Levels of TNF-α and MMP9 expression were also significantly reduced in HPE-treated mice, and oxidative stress was suppressed in the perivascular region. In addition, HPE dose-dependently increased survival of cultured endothelial cells exposed to 100 μM H₂O₂, and it upregulated expression of eNOS and the anti-apoptotic factors bcl-2 and bcl-xL. From these observations, we conclude that HPE ameliorates NASH-associated pathologies by suppressing inflammation, oxidative stress and fibrosis. These beneficially effects of HPE are in part attributable to its protective effects on liver sinusoidal endothelial cells. HPE could thus be an attractive therapeutic candidate with which to suppress progression from simple fatty liver to NASH.

Endogenous Calcitonin Gene-Related Peptide Regulates Lipid Metabolism and Energy Homeostasis in Male Mice

Calcitonin gene-related peptide (CGRP) is a bioactive peptide produced by alternative splicing of the primary transcript of the calcitonin/CGRP gene. CGRP is largely distributed in the cardiovascular and nervous systems, where it acts as a regulatory factor. CGRP is also expressed in organs and tissues involved in metabolic regulation, including white adipose tissue (WAT), where its function is largely unknown. In this study, we examined the effects of endogenous CGRP on metabolic function. When we administered a high-fat diet to CGRP-specific knockout (CGRP-/-) and wild-type (WT) mice for 10 weeks, we observed that food intake did not differ between the two groups, but body weight and visceral fat weight were significantly lower in CGRP-/- mice. Fatty liver changes were less severe in CGRP-/- mice, which also showed lower serum insulin and leptin levels. Glucose tolerance and insulin sensitivity were better in CGRP-/- than WT mice, and expired gas analysis revealed greater oxygen consumption by CGRP-/- mice. Adipocyte hypertrophy was suppressed in CGRP-/- mice, while expression of β-3-adrenergic receptor, hormone-sensitive lipase and adiponectin was enhanced. Isoproterenol-induced glycerol release from WAT was higher in CGRP-/- than WT mice, and CGRP-/- mice showed elevated sympathetic nervous activity. β-receptor-blockade canceled the beneficial effects of CGRP deletion on obesity. These results suggest that, in addition to its actions in the cardiovascular system, endogenous CGRP is a key regulator of metabolism and energy homeostasis in vivo.

Localization of Xenobiotic Transporter OCTN1/SLC22A4 in Hepatic Stellate Cells and Its Protective Role in Liver Fibrosis

Xenobiotic transporters play key roles in disposition of certain therapeutic agents, although limited information is available on their roles other than pharmacokinetic issues. Here, suppressive effect of multispecific organic cation transporter OCTN1/SLC22A4 on liver fibrosis was proposed in liver injury models. After injection of hepatotoxins such as dimethylnitrosamine (DMN) or concanavalin A, hepatic fibrosis, and oxidative stress, evaluated in terms of Sirius red and 4-hydroxy-2-nonenal staining, respectively, were more severe in liver of octn1/slc22a4 gene knockout (octn1(-/-)) mice than that in wild-type mice. DMN treatment markedly increased α-smooth muscle actin and F4/80, markers of activated stellate and Kupffer cells, respectively, in liver of octn1(-/-), but had less effect in wild-type mice. Thus, octn1/slc22a4 gene deletion results in more severe hepatic fibrosis, oxidative stress, and inflammation. DMN-treated wild-type mice showed increased Octn1 staining and hepatic concentration of its food-derived antioxidant ergothioneine (ERGO). The upregulated Octn1 was co-localized with α-smooth muscle actin. Functional expression of Octn1 was demonstrated in activated human hepatic stellate cell lines, LI90 and LX-2. Provision of ERGO-rich feed ameliorated DMN-induced liver fibrosis and oxidative stress. Overall, Octn1 is upregulated in activated stellate cells, resulting in increased delivery of its substrate antioxidant ERGO and a protective effect against liver fibrosis.

Antifibrotic mechanism of deferoxamine in concanavalin A induced-liver fibrosis: Impact on interferon therapy

Iron-overload is a well-known factor of hepatotoxicity and liver fibrosis, which found to be a common finding among hepatitis C virus patients and related to interferon resistance. We aimed to elucidate the potential antifibrotic effect of deferoxamine; the main iron chelator, and its additional usefulness to interferon-based therapy in concanavalin A-induced immunological model of liver fibrosis. Rats were treated with deferoxamine and/or pegylated interferon-α for 6 weeks. Hepatotoxicity indices, oxidative stress, inflammatory and liver fibrosis markers were assessed. Concanavalin A induced a significant increase in hepatotoxicity indices and lipid peroxidation accompanied with a significant depletion of total antioxidant capacity, glutathione level and superoxide dismutase activity. Besides, it increased CD4(+) T-cells content and the downstream inflammatory cascades, including NF-κB, TNF-α, iNOS, COX-2, IL-6 and IFN-γ. Furthermore, α-SMA, TGF-β1 and hydroxyproline were increased markedly, which confirmed by histopathology. Treatment with either deferoxamine or pegylated interferon-α alone reduced liver fibrosis markers significantly and improved liver histology. However, some of the hepatotoxicity indices and oxidative stress markers did not improve upon pegylated interferon-α treatment alone, besides the remarkable increase in IL-6. Combination therapy of deferoxamine with pegylated interferon-α further improved all previous markers, ameliorated IL-6 elevation, as well as increased hepcidin expression. In conclusion, our study provides evidences for the potent antifibrotic effects of deferoxamine and the underlying mechanisms that involved attenuating oxidative stress and subsequent inflammatory cascade, as well as the production of profibrogenic factors. Addition of deferoxamine to interferon regimen for HCV patients may offer a promising adjuvant modality to enhance therapeutic response.

Fenofibrate A peroxisome proliferator activated receptor-α agonist treatment ameliorates Concanavalin A-induced hepatitis in rats

Peroxisome proliferator-activated receptor-α (PPARα) is physiologically highly expressed by hepatocytes, where it plays a pivotal anti-inflammatory and metabolic role. The decrease expression and functional activity of PPARα in hepatocytes during hepatitis C virus infection may contribute to the pathogenesis of the disease in humans. This study aims at evaluating the effects of PPARα activation with fenofibrate (FF) on liver inflammation, fibrosis and portal pressure (PP) in Concanavalin A (Con A)- induced hepatitis in rats. The rats were randomly divided to 3 groups; control (1 ml saline iv/wk) group, Con A (20mg/kg/iv/wk) group and Con A with FF (100mg/kg/day p.o) group. Blood samples and livers were collected by the end of the first, second, fourth and eighth injections of Con A for biochemical, histopathological and immunohistochemistry studies for α-smooth muscle actin (α SMA). Measurement of PP was performed by the end of the 8th week. FF group had a significant (P<0.05) decrease of serum alanine and aspartate aminotransferases with significant reduction of hepatic tumor necrosis factor alpha and malondialdehyde levels than Con A group. Histopathological examination revealed that treatment with FF significantly suppressed early inflammation, reduced α SMA, and apoptosis of hepatocytes induced by Con A, thereby preventing the progression of chronic liver injury and fibrosis. In addition FF group had a significantly lower PP (-89.0%) than Con A group. In conclusion PPARα activation significantly reduced liver inflammation, fibrosis and PP in Con A model of hepatitis that may represent a new therapeutic strategy for hepatitis and its complications.

The significance of CD14+ monocytes in peripheral blood stem cells for the treatment of rat liver cirrhosis

BACKGROUND AIMS

Circulating monocytes have been exploited as an important progenitor cell resource for hepatocytes in vitro and are instrumental in the removal of fibrosis. We investigated the significance of monocytes in peripheral blood stem cells (PBSC) for the treatment of liver cirrhosis.

METHODS

Rat CD14+ monocytes in PBSC were mobilized with granulocyte-colony-stimulating factor (G-CSF) and harvested by magnetic cell sorting (MACS). Female rats with carbon tetrachloride (CCl₄-induced liver cirrhosis were injected CM-DiI-labeled monocytes, CD14⁻ cells (1 x 10⁷ cells/rat) or saline via the portal vein.

RESULTS

Rat CD14+ and CD11b+ monocytes in PBSC were partly positive for CD34, CD45, CD44, Oct3/4 and Sox2, suggesting monocytes with progenitor capacity. Compared with CD14⁻ cell-infused and saline-injected rats, rats undergoing monocyte transplantation showed a gradually increased serum albumin level and decreased portal vein pressure, resulting in a significantly improved survival rate. Meanwhile, monocyte transplantation apparently attenuated liver fibrosis by analysis for fibronectin, α2-(1)-procollagen, α-smooth muscle aorta (SMA) and transforming growth factor (TGF)-β. Transplanted monocytes mainly clustered in periportal areas of liver, in which 1.8% cells expressed hepatocyte marker albumin and CK18. The expression level of hepatocyte growth factor (HGF), TGF-α, extracellular matrix (EGF) and vascular endothelial growth factor (VEGF) increased, while monocyte transplantation enhanced hepatocyte proliferation. On the other hand, the activities and expression of matrix metalloproteinases (MMP) increased while tissue inhibitor of metalloproteinase (TIMP)-1 expression significantly reduced in monocyte-transplanted livers. Some transplanted monocytes expressed MMP-9 and -13.

CONCLUSIONS

The data suggest that CD14+ monocytes in PBSC contribute to hepatocyte regeneration and extracellular matrix (ECM) remodeling in rat liver cirrhosis much more than CD14⁻ cells, and might offer a therapeutic alternative for patients with liver cirrhosis.