Extracellular histones stimulate collagen expression in vitro and promote liver fibrogenesis in a mouse model via the TLR4-MyD88 signaling pathway

BACKGROUND Liver fibrosis progressing to liver cirrhosis and hepatic carcinoma is very common and causes more than one million deaths annually.Fibrosis develops from recurrent liver injury but the molecular mechanisms are not fully understood.Recently,the TLR4-MyD88 signaling pathway has been reported to contribute to fibrosis.Extracellular histones are ligands of TLR4 but their roles in liver fibrosis have not been investigated.AIM To investigate the roles and potential mechanisms of extracellular histones in liver fibrosis.METHODS In vitro,LX2 human hepatic stellate cells(HSCs)were treated with histones in the presence or absence of non-anticoagulant heparin(NAHP)for neutralizing histones or TLR4-blocking antibody.The resultant cellular expression of collagen I was detected using western blotting and immunofluorescent staining.In vivo,the CCl4-induced liver fibrosis model was generated in male 6-week-old ICR mice and in TLR4 or MyD88 knockout and parental mice.Circulating histones were detected and the effect of NAHP was evaluated.RESULTS Extracellular histones strongly stimulated LX2 cells to produce collagen I.Histone-enhanced collagen expression was significantly reduced by NAHP and TLR4-blocking antibody.In CCl4-treated wild type mice,circulating histones were dramatically increased and maintained high levels during the duration of fibrosisinduction.Injection of NAHP not only reduced alanine aminotransferase and liver injury scores,but also significantly reduced fibrogenesis.Since the TLR4-blocking antibody reduced histone-enhanced collagen I production in HSC,the CCl4 model with TLR4 and MyD88 knockout mice was used to demonstrate the roles of the TLR4-MyD88 signaling pathway in CCl4-induced liver fibrosis.The levels of liver fibrosis were indeed significantly reduced in knockout mice compared to wild type parental mice.CONCLUSION Extracellular histones potentially enhance fibrogenesis via the TLR4–MyD88 signaling pathway and NAHP has therapeutic potential by detoxifying extracellular histones.

Immunotherapy-based novel nanoparticles in the treatment of gastrointestinal cancer: Trends and challenges

Gastrointestinal cancer(GIC)is the most common cancer with a poor prognosis.Currently,surgery is the main treatment for GIC.However,the high rate of postoperative recurrence leads to a low five-year survival rate.In recent years,immunotherapy has received much attention.As the only immunotherapy drugs approved by the Food and Drug Administration(FDA),immune checkpoint blockade(ICB)drugs have great potential in cancer therapy.Nevertheless,the efficacy of ICB treatment is greatly limited by the low immunogenicity and immunosuppressive microenvironment of GIC.Therefore,the targets of immunotherapy have expanded from ICB to increasing tumor immunogenicity,increasing the recruitment and maturation of immune cells and reducing the proportion of inhibitory immune cells,such as M2-like macrophages,regulatory T cells and myeloid-derived suppressor cells.Moreover,with the development of nanotechnology,a variety of nanoparticles have been approved by the FDA for clinical therapy,so novel nanodrug delivery systems have become a research focus for anticancer therapy.In this review,we summarize recent advances in the application of immunotherapy-based nanoparticles in GICs,such as gastric cancer,hepatocellular carcinoma,colorectal cancer and pancreatic cancer,and described the existing challenges and future trends.