Effective Amelioration of Liver Fibrosis Through Lentiviral Vector Carrying Toxoplasma gondii gra15II in Murine Model

Studies on the mechanism of Toxoplasma gondii Chinese 1 genotype Wh6 strain causing mice abnormal cognitive behavior

BACKGROUND

Alzheimer's disease presents an abnormal cognitive behavior. TgCtwh6 is one of the predominant T. gondii strains prevalent in China. Although T. gondii type II strain infection can cause host cognitive behavioral abnormalities, we do not know whether TgCtwh6 could also cause host cognitive behavioral changes. So, in this study, we will focus on the effect of TgCtwh6 on mouse cognitive behavior and try in vivo and in vitro to explore the underlying mechanism by which TgCtwh6 give rise to mice cognitive behavior changes at the cellular and molecular level.

METHODS

C57BL/6 mice were infected orally with TgCtwh6 cysts. From day 90 post-infection on, all mice were conducted through the open field test and then Morris water maze test to evaluate cognitive behavior. The morphology and number of cells in hippocampus were examined with hematoxylin-eosin (H&E) and Nissl staining; moreover, Aβ protein in hippocampus was determined with immunohistochemistry and thioflavin S plaque staining. Synaptotagmin 1, apoptosis-related proteins, BACE1 and APP proteins and genes from hippocampus were assessed by western blotting or qRT-PCR. Hippocampal neuronal cell line or mouse microglial cell line was challenged with TgCtwh6 tachyzoites and then separately cultured in a well or co-cultured in a transwell device. The target proteins and genes were analyzed by immunofluorescence staining, western blotting and qRT-PCR. In addition, mouse microglial cell line polarization state and hippocampal neuronal cell line apoptosis were estimated using flow cytometry assay.

RESULTS

The OFT and MWMT indicated that infected mice had cognitive behavioral impairments. The hippocampal tissue assay showed abnormal neuron morphology and a decreased number in infected mice. Moreover, pro-apoptotic proteins, as well as BACE1, APP and Aβ proteins, increased in the infected mouse hippocampus. The experiments in vitro showed that pro-apoptotic proteins and p-NF-κBp65, NF-κBp65, BACE1, APP and Aβ proteins or genes were significantly increased in the infected HT22. In addition, CD80, pro-inflammatory factors, notch, hes1 proteins and genes were enhanced in the infected BV2. Interestingly, not only the APP and pro-apoptotic proteins in HT22, but also the apoptosis rate of HT22 increased after the infected BV2 were co-cultured with the HT22 in a transwell device.

CONCLUSIONS

Neuron apoptosis, Aβ deposition and neuroinflammatory response involved with microglia polarization are the molecular and cellular mechanisms by which TgCtwh6 causes mouse cognitive behavioral abnormalities.

Macrophage Polarization and Its Role in Liver Disease

Macrophages are important immune cells in innate immunity, and have remarkable heterogeneity and polarization. Under pathological conditions, in addition to the resident macrophages, other macrophages are also recruited to the diseased tissues, and polarize to various phenotypes (mainly M1 and M2) under the stimulation of various factors in the microenvironment, thus playing different roles and functions. Liver diseases are hepatic pathological changes caused by a variety of pathogenic factors (viruses, alcohol, drugs, etc.), including acute liver injury, viral hepatitis, alcoholic liver disease, metabolic-associated fatty liver disease, liver fibrosis, and hepatocellular carcinoma. Recent studies have shown that macrophage polarization plays an important role in the initiation and development of liver diseases. However, because both macrophage polarization and the pathogenesis of liver diseases are complex, the role and mechanism of macrophage polarization in liver diseases need to be further clarified. Therefore, the origin of hepatic macrophages, and the phenotypes and mechanisms of macrophage polarization are reviewed first in this paper. It is found that macrophage polarization involves several molecular mechanisms, mainly including TLR4/NF-κB, JAK/STATs, TGF-β/Smads, PPARγ, Notch, and miRNA signaling pathways. In addition, this paper also expounds the role and mechanism of macrophage polarization in various liver diseases, which aims to provide references for further research of macrophage polarization in liver diseases, contributing to the therapeutic strategy of ameliorating liver diseases by modulating macrophage polarization.

Hepatic macrophages: Key players in the development and progression of liver fibrosis

Hepatic fibrosis is a common pathological process involving persistent liver injury with various etiologies and subsequent inflammatory responses that occur in chronic liver diseases. If left untreated, liver fibrosis can progress to liver cirrhosis, hepatocellular carcinoma and eventually, liver failure. Unfortunately, to date, there is no effective treatment for liver fibrosis, with the exception of liver transplantation. Although the pathophysiology of liver fibrosis is multifactorial and includes the activation of hepatic stellate cells, which are known to drive liver fibrogenesis, hepatic macrophages have emerged as central players in the development of liver fibrosis and regression. Hepatic macrophages, which consist of resident macrophages (Kupffer cells) and monocyte-derived macrophages, have been shown to play an intricate role in the initiation of inflammatory responses to liver injury, progression of fibrosis, and promotion of fibrosis resolution. These features have made hepatic macrophages uniquely attractive therapeutic targets in the fight against hepatic fibrosis. In this review, we synthesised the literature to highlight the functions and regulation of heterogeneity in hepatic macrophages. Furthermore, using the existing findings, we attempt to offer insights into the molecular mechanisms underlying the phenotypic switch from fibrogenic macrophages to restorative macrophages, the regulation of heterogeneity, and modes of action for hepatic macrophages. A better understanding of these mechanisms may guide the development of novel anti-fibrotic therapies (eg macrophage subset-targeted treatments) to combat liver fibrosis in the future.

Prior Toxoplasma Gondii Infection Ameliorates Liver Fibrosis Induced by Schistosoma Japonicum through Inhibiting Th2 Response and Improving Balance of Intestinal Flora in Mice

Schistosomiasis is an immunopathogenic disease in which a T helper (Th) cell type 2-like response plays vital roles. Hepatic fibrosis is its main pathologic manifestations, which is the leading cause of hepatic cirrhosis. Co-infections of Schistosoma japonicum (Sj) with other pathogens are frequently encountered but are easily ignored in clinical studies, and effective therapeutic interventions are lacking. In this study, we explored the effect of Toxoplasma gondii (Tg) prior infection on Th1/Th2 response, community shifts in gut microbiome (GM), and the pathogenesis of schistosomiasis in murine hosts. Mice were prior infected with Tg before Sj infection. The effects of co-infection on Th1/Th2 response and hepatic fibrosis were analyzed. Furthermore, we investigated this issue by sequencing 16S rRNA from fecal specimens to define the GM profiles during co-infection. Tg prior infection markedly reduced the granuloma size and collagen deposit in livers against Sj infection. Prior infection promoted a shift toward Th1 immune response instead of Th2. Furthermore, Tg infection promoted the expansion of preponderant flora and Clostridiaceae was identified as a feature marker in the GM of the co-infection group. Redundancy analysis (RDA)/canonical correspondence analysis (CCA) results showed that liver fibrosis, Th1/Th2 cytokines were significantly correlated (P < 0.05) with the GM compositions. Tg infection inhibits hepatic fibrosis by downregulating Th2 immune response against Sj infection, and further promotes the GM shifts through "gut-liver axis" in the murine hosts. Our study may provide insights into potential anti-fibrosis strategies in co-infection individuals.

The role of microRNAs in the pathogenesis, grading and treatment of hepatic fibrosis in schistosomiasis

Schistosomiasis is a prevalent parasitic disease worldwide. The main pathological changes of hepatosplenic schistosomiasis are hepatic granuloma and fibrosis due to worm eggs. Portal hypertension and ascites induced by hepatic fibrosis are usually the main causes of death in patients with chronic hepatosplenic schistosomiasis. Currently, no effective vaccine exists for preventing schistosome infections. For quite a long time, praziquantel (PZQ) was widely used for the treatment of schistosomiasis and has shown benefit in treating liver fibrosis. However, drug resistance and chemical toxicity from PZQ are being increasingly reported in recent years; therefore, new and effective strategies for treating schistosomiasis-induced hepatic fibrosis are urgently needed. MicroRNA (miRNA), a non-coding RNA, has been proved to be associated with the development of many human diseases, including schistosomiasis. In this review, we present a balanced and comprehensive view of the role of miRNAs in the pathogenesis, grading, and treatment of schistosomiasis-associated hepatic fibrosis. The multiple regulatory roles of miRNAs, such as promoting or inhibiting the development of liver pathology in murine schistosomiasis are also discussed in depth. Additionally, miRNAs may serve as candidate biomarkers for diagnosing liver pathology of schistosomiasis and as novel therapeutic targets for treating schistosomiasis-associated hepatic fibrosis.

Research progress on the anti-hepatic fibrosis action and mechanism of natural products

Hepatic fibrosis is the most common pathological feature of most chronic liver diseases, and its continuous deterioration gradually develops into liver cirrhosis and eventually leads to liver cancer. At present, there are many kinds of drugs used to treat liver fibrosis. However, Western drugs tend to only target single genes/proteins and induce many adverse reactions. Most of the mechanisms and active ingredients of traditional Chinese medicine (TCM) are not clear, and there is a lack of unified diagnosis and treatment standards. Natural products, which are characterized by structural diversity, low toxicity, and origination from a wide range of sources, have unique advantages and great potential in anti-liver fibrosis. This article summarizes the work done over the previous decade, on the active ingredients in natural products that are reported to have anti-hepatic fibrosis effects. The effective anti-hepatic fibrosis ingredients identified can be generally divided into flavonoids, saponins, polysaccharides and alkaloids. Mechanisms of anti-liver fibrosis include inhibition of liver inflammation, anti-lipid peroxidation injury, inhibition of the activation and proliferation of hepatic stellate cells (HSCs), modulation of the synthesis and secretion of pro-fibrosis factors, and regulation of the synthesis and degradation of the extracellular matrix (ECM). This review provides suggestions for the development of anti-hepatic fibrosis drugs.

Anti-Toxoplasma activity of silver nanoparticles green synthesized with Phoenix dactylifera and Ziziphus spina-christi extracts which inhibits inflammation through liver regulation of cytokines in Balb/c mice

Toxoplasmosis constitutes a global infection caused by oblige intracellular apicomplexan protozoan parasite Toxoplasma gondii Although often asymptomatic, infection can result in more severe, potentially life threatening symptoms particularly in immunocompromised individuals. The present study evaluated the anti-Toxoplasma effects in experimental animals of silver nanoparticles synthesized in combination with extracts of natural plants (Phoenix dactylifera and Ziziphus spina-christi) as an alternative method to standard sulfadiazine drug therapy. Liver functions estimated by and AST and ALT were significantly increased in T. gondii-infected mice compared with the control group as well as hepatic nitric oxide (NO), lipid peroxidation (LPO) levels and caused significant decrease in superoxide dismutase (SOD), catalase (CAT) and glutathione activities in the liver homogenates. Nanoparticles pretreatment prevented liver damage as determined by enzyme activity inhibition, in addition to significant inhibition of hepatic NO levels and significant elevation in liver SOD and CAT activities. Moreover, nanoparticle treatment significantly decreased hepatic LPO and NO concentrations and proinflammatory cytokines but significantly boosted the antioxidant enzyme activity of liver homogenate. In addition, histological examinations showed distinct alterations in the infected compared with untreated control groups. Conversely, nanoparticles pretreatment showed improvement in the histological features indicated by slight infiltration and fibrosis, minimal pleomorphism and less hepatocyte and degeneration. Furthermore, nanoparticles treatment induced a reduction in immunoreactivity to TGF-β and NF-κB in hepatic tissues. Therefore, the present study provides new insights into various natural plants that are used traditionally for the treatment of toxoplasmosis and other parasitic infections, which may be useful as alternative treatment option for T. gondii infections.