Macrophages contribute to liver repair after monocrotaline-induced liver injury via SDF-1/CXCR4

Cannabidiol may prevent the development of congestive hepatopathy secondary to right ventricular hypertrophy associated with pulmonary hypertension in rats

BACKGROUND

Pulmonary hypertension (PH) can cause right ventricular (RV) failure and subsequent cardiohepatic syndrome referred to as congestive hepatopathy (CH). Passive blood stasis in the liver can affect inflammation, fibrosis, and ultimately cirrhosis. Cannabidiol (CBD) has many beneficial properties including anti-inflammatory and reduces RV systolic pressure and RV hypertrophy in monocrotaline (MCT)-induced PH in rats. Thus, it suggests that CBD may have the potential to limit CH development secondary to RV failure. The present study aimed to determine whether chronic administration of CBD can inhibit the CH secondary to RV hypertrophy associated with MCT-induced PH.

METHODS

The experiments involved rats with and without MCT-induced PH. CBD (10 mg/kg) or its vehicle was administered once daily for 3 weeks after MCT injection (60 mg/kg).

RESULTS

Monocrotaline administration increased the liver/body weight ratio. In histology examinations, we observed necrosis and vacuolar degeneration of hepatocytes as well as sinusoidal congestion. In biochemical studies, we observed increased levels of nuclear factor-κappa B (NF-κB), tumour necrosis factor-alpha (TNA-α), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6). CBD administration to PH rats reduced the liver/body weight ratio, improved the architecture of the liver, and inhibited the formation of necrosis. Cannabidiol also decreased the level of NF-κB, TNF-α, IL-1β and IL-6.

CONCLUSIONS

The studies show that CBD can protect the liver from CH probably through attenuating PH, protective effects on the RV, and possibly direct anti-inflammatory effects on liver tissue through regulation of the NF-κB pathway.

A biologically active lipid, thromboxane, as a regulator of angiogenesis and lymphangiogenesis

Thromboxane (TX) and prostaglandins are metabolites of arachidonic acid, a twenty-carbon unsaturated fatty acid, and have a variety of actions that are exerted via specific receptors. Angiogenesis is defined as the formation of new blood vessels from pre-existing vascular beds and is a critical component of pathological conditions, including inflammation and cancer. Lymphatic vessels play crucial roles in the regulation of interstitial fluid, immune surveillance, and the absorption of dietary fat from the intestine; and they are also involved in the pathogenesis of various diseases. Similar to angiogenesis, lymphangiogenesis, the formation of new lymphatic vessels, is a critical component of pathological conditions. The TP-dependent accumulation of platelets in microvessels has been reported to enhance angiogenesis under pathological conditions. Although the roles of some growth factors and cytokines in angiogenesis and lymphangiogenesis have been well characterized, accumulating evidence suggests that TX induces the production of proangiogenic and prolymphangiogenic factors through the activation of adenylate cyclase, and upregulates angiogenesis and lymphangiogenesis under disease conditions. In this review, we discuss the role of TX as a regulator of angiogenesis and lymphangiogenesis, and its emerging importance as a therapeutic target.

miR-155 Derived from Bone Marrow Mesenchymal Stem Cell-Secreted Exosomes Reduces Kidney Rejection in Rat Allogeneic Transplantation Model via SDF-1/CXCR4

Aberrantly expressed miR-155 is associated with renal rejection after allogeneic transplantation. This study mainly explored the mechanism of miR-155 derived from bone marrow mesenchymal stem cell-secreted exosomes (BMSC-exo) in renal rejection after allogeneic transplantation. Thirty Fischer rats and 40 Lewis rats were used as donors and recipients, respectively. The Lewis rats were randomized into 4 groups (10 rats per group): Control group, miR-155 group, positive control group and CXCR4 agonist group. The following indicators were monitored in BMSC-exo: miR-155 expression, serum creatinine level, renal histopathological changes, CADI score, number of cells that were positive for TGF-β, Smad3 and α-SMA, as well as the protein levels of Smad3, TGF-β, CXCR4 and SDF-1. miR-155 expression in BMSC-exo was significantly higher than that in HKb-20 cells. On the 7th day after surgery, the serum creatinine levels of rats in the miR-155 group and positive control group reduced significantly, while decreasing slowly in the control group and CXCR4 agonist group. The CADI scores of rats in the miR-155 group and positive control group were significantly higher than those in the control group and CXCR4 agonist group (P < 0.05). No significant difference was found either between the miR-155 group and positive control group, or between the control group and CXCR4 agonist group (P > 0.05). Rats in the control group and CXCR4 agonist group had more cells that were positive for TGF-β, Smad3 and α-SMA, while those in the miR-155 group and positive control group showed less. The Smad3, TGF-β, CXCR4 and SDF-1 proteins were weakly expressed in the miR-155 group and positive control group, but strongly expressed in the control group and CXCR4 agonist group. No significant difference in the protein levels was found either between the miR-155 group and positive control group, or between the control group and CXCR4 agonist group (P > 0.05). miR-155 derived from BMSC-exo is protective against allogeneic kidney transplantation. Specifically, BMSC-exo-derived miR-155 blocked the activity of SDF-1/CXCR4 and TGF-β/Smad3 pathways, thereby downregulating the expression of α-SMA. As a result, it ameliorated renal fibrosis and alleviated renal dysfunction, ultimately leading to the prevention and reduction of renal rejection following allograft transplantation.

Bone Marrow Mesenchymal Stem Cell (BMSC) Restrains the Angiogenesis in Melanoma Through Stromal-Derived-Factor-1/C-X-C Chemokine Receptor Type 4 (SDF-1/CXCR4)

This study analyzes the effect of BMSC on restraining the angiogenesis in melanoma through inducing SDF-1/CXCR4 channel. 50 female naked rates were equally assigned into NC group, model group, BMSC group, agonist group and positive NC group randomly followed by analysis of pathological changes, and the level of HIF-1, VEG, MVD, SDF-1 and CXCR4. Agonist group showed the highest level of HIF-1α and VEGF and MVD followed by, model group BMSC group, positive NC group and NC group with no different between BMSC group and positive NC group. SDF-1 and CXCR4 expression was highest in agonist group, followed by that in model group, positive NC group, BMSC group and NC group without difference between model group and positive NC group. In conclusion, SDF-1/CXCR4 activity could be restrained by BMSC partly along with reduced level of HIF-1α and VEGF. This is mainly related with restraining the SDF-1/CXCR4 channel, indicating that it could be adopted as a brand-new therapeutic target for treating melanoma.

Cancer cells produce liver metastasis via gap formation in sinusoidal endothelial cells through proinflammatory paracrine mechanisms

Intracellular gap (iGap) formation in liver sinusoidal endothelial cells (LSECs) is caused by the destruction of fenestrae and appears under pathological conditions; nevertheless, their role in metastasis of cancer cells to the liver remained unexplored. We elucidated that hepatotoxin-damaged and fibrotic livers gave rise to LSECs-iGap formation, which was positively correlated with increased numbers of metastatic liver foci after intrasplenic injection of Hepa1-6 cells. Hepa1-6 cells induced interleukin-23-dependent tumor necrosis factor-α (TNF-α) secretion by LSECs and triggered LSECs-iGap formation, toward which their processes protruded to transmigrate into the liver parenchyma. TNF-α triggered depolymerization of F-actin and induced matrix metalloproteinase 9 (MMP9), intracellular adhesion molecule 1, and CXCL expression in LSECs. Blocking MMP9 activity by doxycycline or an MMP2/9 inhibitor eliminated LSECs-iGap formation and attenuated liver metastasis of Hepa1-6 cells. Overall, this study revealed that cancer cells induced LSEC-iGap formation via proinflammatory paracrine mechanisms and proposed MMP9 as a favorable target for blocking cancer cell metastasis to the liver.

Autophagy Promotes the Survival of Adipose Mesenchymal Stem/Stromal Cells and Enhances Their Therapeutic Effects in Cisplatin-Induced Liver Injury via Modulating TGF-β1/Smad and PI3K/AKT Signaling Pathways

Autophagy is a key metabolic process where cells can recycle its proteins and organelles to regenerate its own cellular building blocks. Chemotherapy is indispensable for cancer treatment but associated with various side-effects, including organ damage. Stem cell-based therapy is a promising approach for reducing chemotherapeutic side effects, however, one of its main culprits is the poor survival of transplanted stem cells in damaged tissues. Here, we aimed to test the effects of activating autophagy in adipose-derived mesenchymal stem/stromal cells (ADSCs) on the survival of ADSCs, and their therapeutic value in cisplatin-induced liver injury model. Autophagy was activated in ADSCs by rapamycin (50 nM/L) for two hours before transplantation and were compared to non-preconditioned ADSCs. Rapamycin preconditioning resulted in activated autophagy and improved survival of ADSCs achieved by increased autophagosomes, upregulated autophagy-specific LC3-II gene, decreased protein degradation/ubiquitination by downregulated p62 gene, downregulated mTOR gene, and finally, upregulated antiapoptotic BCL-2 gene. In addition, autophagic ADSCs transplantation in the cisplatin liver injury model, liver biochemical parameters (AST, ALT and albumin), lipid peroxidation (MDA), antioxidant profile (SOD and GPX) and histopathological picture were improved, approaching near-normal conditions. These promising autophagic ADSCs effects were achieved by modulation of components in TGF-β1/Smad and PI3K-AKT signaling pathways, besides reducing NF-κB gene expression (marker for inflammation), reducing TGF-β1 levels (marker for fibrosis) and increasing SDF-1 levels (liver regeneration marker) in liver. Therefore, current results highlight the importance of autophagy in augmenting the therapeutic potential of stem cell therapy in alleviating cisplatin-associated liver damage and opens the path for improved cell-based therapies, in general, and with chemotherapeutics, in particular.