Chemokine Cxcl9 attenuates liver fibrosis-associated angiogenesis in mice

Cxcl9-deficiency attenuates the progression of post-traumatic osteoarthritis in mice

OBJECTIVE

Osteoarthritis (OA) is one of the leading causes of disability in the aging population. While about 10% of the adult population is affected by OA, there is to date no curative treatment and joint replacement surgery remains the only option for treating end-stage OA. Previous studies found elevated levels of the chemokine C-X-C motif ligand 9 (CXCL9) in the synovial fluid of OA knees. However, the exact role of CXCL9 in OA progression is still unknown.

METHODS

Female wild-type and Cxcl9-deficient mice were challenged with a unilateral anterior cruciate ligament transection (ACLT). Joint destruction in early and late stages of experimental OA was assessed using micro-CT scanning, histological scoring, histomorphometry, and gene expression analysis.

RESULTS

Inactivation of Cxcl9 protected from cartilage destruction and osteophyte formation in post-traumatic OA in mice. Similarly, indices of joint inflammation including synovitis and expression of pro-inflammatory interleukin-1beta were reduced in OA knees of Cxcl9-deficient mice. However, bone erosion and pathophysiological changes in the subchondral bone compartment remained unaffected in Cxcl9-deficient mice with experimental OA.

CONCLUSION

Our results point towards a pro-inflammatory role of CXCL9 in OA and identify a potential new target for the pharmacological treatment of OA.

Hepatitis D virus infection triggers CXCL9-11 upregulation in hepatocytes and liver infiltration of CXCR3+ CD4 T cells

Background & Aims

The role of hepatocytes in producing chemokines and triggering liver inflammation and damage in chronic hepatitis D (CHD) is not fully understood. Herein, we investigated the contribution of primary human hepatocytes (PHHs) infected with HDV in triggering inflammation by producing the chemokines CXCL9-11.

Methods

We performed quantitative PCR, RNA in situ hybridisation, activation-induced marker (AIM) assays, and FACS analysis to investigate the CXCR3/CXCL9-11 receptor/ligand axis of T cells in peripheral blood and livers from patients with chronic hepatitis B (n = 27 and 18, respectively) and CHD (n = 20 and 18, respectively). Chemokine expression was investigated in cultured HDV-infected PHHs and in livers of HBV- or HBV/HDV-infected humanised mice in the presence or absence of adoptively transferred human immune cells (n = 35 in total).

Results

In patient and chimeric mouse livers, higher expression levels of CXCL9-11 were found in an HBV/HDV-coinfected vs. HBV-mono-infected setting. Similarly, high levels of CXCL9-11 were observed in HDV-infected PHHs in vitro. Analysis by RNA in situ hybridisation on patient livers revealed that HDV-infected hepatocytes were a significant contributor to the chemokine expression. The corresponding chemokine receptor CXCR3 was found upregulated specifically on peripheral bulk CD4 T cells of patients with CHD. CXCR3 upregulation was unspecific and was not detected on HDAg- or HBsAg-specific CD4 T cells by activation-induced marker assay. Lastly, adoptive transfer of human T cells in humanised mice led to recruitment of non-HBV/HDV-specific CD4+ T cells only in the setting of HBV/HDV coinfection, but not in HBV-mono-infected mice.

Conclusions

HDV infection upregulated the intrahepatic expression of the CXCL9-11/CXCR3 receptor/ligand axis. Higher amounts of HBV/HDV-unspecific CD4 T cells expressing CXCR3 may contribute to the aggravated liver inflammation frequently observed in patients with CHD.

Impact and implications

Chronic hepatitis D (CHD) causes the most severe form of viral hepatitis, and treatment options are still limited; therefore, a more precise understanding of CHD immunopathology is needed. In this study, we demonstrated that HDV infection triggers CXCL9-11 expression in hepatocytes and liver infiltration of CXCR3-expressing CD4 T cells in preclinical models as well as patient biopsies. Because recruitment of Th1-polarised CD4 T cells to the liver has been also described for other severe liver diseases, such as autoimmune hepatitis, it may represent an important mechanism of aggravating liver diseases. The data of this study set hereby the basis for future studies analysing phenotype and function of intrahepatic T cells in CHD.

Incomplete elimination of viral genomes is associated with chronic inflammation in nonhuman primate livers after AAV-mediated gene transfer

The liver is a unique organ where immunity can be biased toward ineffective response notably in the context of viral infections. Chronic viral hepatitis depends on the inability of the T-cell immune response to eradicate antigen. In the case of recombinant Adeno-Associated-Virus, used for therapeutic gene transfer, conflicting reports describe tolerance induction to different transgene products while other studies have shown conventional cytotoxic CD8+ T cell responses with a rapid loss of transgene expression. We performed a 1 year follow up of 6 non-human primates after all animals received an rAAV8 vector carrying the GFP transgene at doses of 7×1012 vg/kg. We report that despite anti-GFP peripheral cellular response and loss of hepatic transgene expression, we were still able to detect persisting viral genomes in the liver until 1-year post-injection. These viral genomes were associated with liver inflammation, fibrosis and signs of CD8 T cell exhaustion, including high expression of PD-1. Our study shows that AAV8-mediated gene transfer can results to loss of transgene expression in liver and chronic inflammation several months after gene transfer.

Targeting Ligand Independent Tropism of siRNA-LNP by Small Molecules for Directed Therapy of Liver or Myeloid Immune Cells

Hepatic clearance of lipid nanoparticles (LNP) with encapsulated nucleic acids restricts their therapeutic applicability. Therefore, tools for regulating hepatic clearance are of high interest for nucleic acid delivery. To this end, this work employs wild-type (WT) and low-density lipoprotein receptor (Ldlr)-/- mice pretreated with either a leukotriene B4 receptor inhibitor (BLT1i) or a high-density lipoprotein receptor inhibitor (HDLRi) prior to the injection of siRNA-LNP. This work is able to demonstrate significantly increased hepatic uptake of siRNA-LNP by the BLT1i in Ldlr-/- mice by in vivo imaging and discover an induction of specific uptake-related proteins. Irrespective of the inhibitors and Ldlr deficiency, the siRNA-LNP induced RNA-binding and transport-related proteins in liver, including haptoglobin (HP) that is also identified as most upregulated serum protein. This work observes a downregulation of proteins functioning in hepatic detoxification and of serum opsonins. Most strikingly, the HDLRi reduces hepatic uptake and increases siRNA accumulation in spleen and myeloid immune cells of blood and liver. RNA sequencing demonstrates leukocyte recruitment by the siRNA-LNP and the HDLRi through induction of chemokine ligands in liver tissue. The data provide insights into key mechanisms of siRNA-LNP biodistribution and indicate that the HDLRi has potential for extrahepatic and leukocyte targeting.

Angiocrine signaling in sinusoidal homeostasis and liver diseases

The hepatic sinusoids are composed of liver sinusoidal endothelial cells (LSECs), which are surrounded by hepatic stellate cells (HSCs) and contain liver-resident macrophages called Kupffer cells, and other patrolling immune cells. All these cells communicate with each other and with hepatocytes to maintain sinusoidal homeostasis and a spectrum of hepatic functions under healthy conditions. Sinusoidal homeostasis is disrupted by metabolites, toxins, viruses, and other pathological factors, leading to liver injury, chronic liver diseases, and cirrhosis. Alterations in hepatic sinusoids are linked to fibrosis progression and portal hypertension. LSECs are crucial regulators of cellular crosstalk within their microenvironment via angiocrine signaling. This review discusses the mechanisms by which angiocrine signaling orchestrates sinusoidal homeostasis, as well as the development of liver diseases. Here, we summarise the crosstalk between LSECs, HSCs, hepatocytes, cholangiocytes, and immune cells in health and disease and comment on potential novel therapeutic methods for treating liver diseases.

Aqueous humor cytokine levels in patients with subretinal fibrosis in neovascular age-related macular degeneration

PURPOSE

To investigate aqueous humor cytokine levels in neovascular age-related macular degeneration (nAMD) patients with subretinal fibrosis and to explore the relationship between cytokine levels and disease severity.

METHODS

The aqueous humor samples were collected from 16 eyes with subretinal fibrosis due to nAMD (SRFi group), 33 eyes with nAMD without subretinal fibrosis (nAMD group) and 28 eyes with cataract patients (control group). Clinical samples were analyzed for 5 cytokines,including vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), basic fibroblast growth factor (bFGF), transforming growth factor-α (TGF-α), platelet-derived growth factor-BB (PDGF-BB).

RESULTS

Aqueous humor cytokines VEGF and bFGF were significantly higher in nAMD patients than controls (all P < 0.05), and VEGF, bFGF and TGF-α levels were significantly higher in SRFi patients than controls (all P < 0.05). No significant differences in 4 cytokine levels were observed between nAMD and SRFi patients in aqueous humor. We also identified a positive correlation between the aqueous humor levels of IL-6 and VEGF in the SRFi group, while bFGF and TGF-α in the nAMD group. Moreover, VEGF levels were strongly related to BCVA, and bFGF levels were positively related to the maximum thickness of subretinal hyperreflective material (SHRM) in fibrosis due to nAMD.

CONCLUSION

VEGF and bFGF levels in aqueous humor were elevated in macular neovascularization with and without subretinal fibrosis. TGF-α levels exclusively differed in neovascular AMD with fibrosis. Cytokines are distributed differently and play a synergistic role in different stages (angiogenesis and fibrogenesis) of nAMD. The bFGF levels could predict the negative prognosis in fibrosis due to nAMD.

The Pathophysiology of Portal Hypertension

This article reviews the pathophysiology of portal hypertension that includes multiple mechanisms internal and external to the liver. This article starts with a review of literature describing the cellular and molecular mechanisms of portal hypertension, microvascular thrombosis, sinusoidal venous congestion, portal angiogenesis, vascular hypocontractility, and hyperdynamic circulation. Mechanotransduction and the gut-liver axis, which are newer areas of research, are reviewed. Dysfunction of this axis contributes to chronic liver injury, inflammation, fibrosis, and portal hypertension. Sequelae of portal hypertension are discussed in subsequent studies.

Inflammatory Response in the Pathogenesis and Treatment of Hepatocellular Carcinoma: A Double-Edged Weapon

Hepatocellular carcinoma (HCC) is the most frequent among primary liver tumors (90%) and one of the main causes of cancer-related death. It develops usually in a chronically inflamed environment, ranging from compensatory parenchymal regeneration to fibrosis and cirrhosis: carcinogenesis can potentially happen in each of these stages. Inflammation determined by chronic viral infection (hepatitis B, hepatitis C, and hepatitis delta viruses) represents an important risk factor for HCC etiology through both viral direct damage and immune-related mechanisms. The deregulation of the physiological liver immunological network determined by viral infection can lead to carcinogenesis. The recent introduction of immunotherapy as the gold-standard first-line treatment for HCC highlights the role of the immune system and inflammation as a double-edged weapon in both HCC carcinogenesis and treatment. In this review we highlight how the inflammation is the key for the hepatocarcinogenesis in viral, alcohol and metabolic liver diseases.

Mimicking chronic alcohol effects through a controlled and sustained ethanol release device

Alcohol consumption, a pervasive societal issue, poses considerable health risks and socioeconomic consequences. Alcohol-induced hepatic disorders, such as fatty liver disease, alcoholic hepatitis, chronic hepatitis, liver fibrosis, and cirrhosis, underscore the need for comprehensive research. Existing challenges in mimicking chronic alcohol exposure in cellular systems, attributed to ethanol evaporation, necessitate innovative approaches. In this study, we developed a simple, reusable, and controllable device for examining the physiological reactions of hepatocytes to long-term alcohol exposure. Our approach involved a novel device designed to continuously release ethanol into the culture medium, maintaining a consistent ethanol concentration over several days. We evaluated device performance by examining gene expression patterns and cytokine secretion alterations during long-term exposure to ethanol. These patterns were correlated with those observed in patients with alcoholic hepatitis. Our results suggest that our ethanol-releasing device can be used as a valuable tool to study the mechanisms of chronic alcohol-mediated hepatic diseases at the cellular level. Our device offers a practical solution for studying chronic alcohol exposure, providing a reliable platform for cellular research. This innovative tool holds promise for advancing our understanding of the molecular processes involved in chronic alcohol-mediated hepatic diseases. Future research avenues should explore broader applications and potential implications for predicting and treating alcohol-related illnesses.

Comparison of Inflammatory Cytokine Levels in Hepatic and Jugular Veins of Patients with Cirrhosis

Background

Systemic inflammation with elevated inflammatory cytokines is a hallmark in patients with cirrhosis and the main driver of decompensation. There is insufficient data on whether inflammatory cytokine levels differ between hepatic and jugular veins, which may have implications for further immunological studies.

Methods

Blood from the hepatic and jugular veins of 40 patients with cirrhosis was collected during hepatic venous pressure gradient (HVPG) measurements. Serum levels of 13 inflammatory cytokines (IL-1β, Int-α2, Int-γ, TNF-α, MCP-1, IL-6, IL-8, IL-10, IL-12p70, IL-17A, IL-18, IL-23, and IL-33) were quantified by cytometric bead array.

Results

Cytokine levels of IFN-α2, IFN-γ, TNF-α, IL-6, IL-8, IL-10, IL-17A, IL-18, IL-23, and IL-33 were significantly elevated in patients with decompensated cirrhosis compared to patients with compensated cirrhosis. When comparing patients with clinically significant portal hypertension (CSPH, HVPG ≥ 10 mmHg) to patients without CSPH, there were significantly enhanced serum levels of IL-6 and IL-18 in the former group. There was no significant difference between cytokine serum levels between blood obtained from the jugular versus hepatic veins. Even in subgroup analyses stratified for an early cirrhosis stage (Child-Pugh (CP) A) or more decompensated stages (CP B/C), cytokine levels were similar.

Conclusion

Cytokine levels increase with decompensation and increasing portal hypertension in patients with cirrhosis. There is no relevant difference in cytokine levels between hepatic and jugular blood in patients with cirrhosis.

VEGF signaling governs the initiation of biliary-mediated liver regeneration through the PI3K-mTORC1 axis

Biliary epithelial cells (BECs) are a potential source to repair the damaged liver when hepatocyte proliferation is compromised. Promotion of BEC-to-hepatocyte transdifferentiation could be beneficial to the clinical therapeutics of patients with end-stage liver diseases. However, mechanisms underlying the initiation of BEC transdifferentiation remain largely unknown. Here, we show that upon extreme hepatocyte injury, vegfaa and vegfr2/kdrl are notably induced in hepatic stellate cells and BECs, respectively. Pharmacological and genetic inactivation of vascular endothelial growth factor (VEGF) signaling would disrupt BEC dedifferentiation and proliferation, thus restraining hepatocyte regeneration. Mechanically, VEGF signaling regulates the activation of the PI3K-mammalian target of rapamycin complex 1 (mTORC1) axis, which is essential for BEC-to-hepatocyte transdifferentiation. In mice, VEGF signaling exerts conserved roles in oval cell activation and BEC-to-hepatocyte differentiation. Taken together, this study shows VEGF signaling as an initiator of biliary-mediated liver regeneration through activating the PI3K-mTORC1 axis. Modulation of VEGF signaling in BECs could be a therapeutic approach for patients with end-stage liver diseases.

Targeted VEGFA therapy in regulating early acute kidney injury and late fibrosis

Damage to peritubular capillaries is a key process that contributes to acute kidney injury (AKI) progression. Vascular endothelial growth factor A (VEGFA) plays a critical role in maintaining the renal microvasculature. However, the physiological role of VEGFA in various AKI durations remains unclear. A severe unilateral ischemia‒reperfusion injury model was established to provide an overview of VEGFA expression and the peritubular microvascular density from acute to chronic injury in mouse kidneys. Therapeutic strategies involving early VEGFA supplementation protecting against acute injury and late anti-VEGFA treatment for fibrosis alleviation were analyzed. A proteomic analysis was conducted to determine the potential mechanism of renal fibrosis alleviation by anti-VEGFA. The results showed that two peaks of extraglomerular VEGFA expression were observed during AKI progression: one occurred at the early phase of AKI, and the other occurred during the transition to chronic kidney disease (CKD). Capillary rarefaction progressed despite the high expression of VEGFA at the CKD stage, and VEGFA was associated with interstitial fibrosis. Early VEGFA supplementation protected against renal injury by preserving microvessel structures and counteracting secondary tubular hypoxic insults, whereas late anti-VEGFA treatment attenuated renal fibrosis progression. The proteomic analysis highlighted an array of biological processes related to fibrosis alleviation by anti-VEGFA, which included regulation of supramolecular fiber organization, cell-matrix adhesion, fibroblast migration, and vasculogenesis. These findings establish the landscape of VEGFA expression and its dual roles during AKI progression, which provides the possibility for the orderly regulation of VEGFA to alleviate early acute injury and late fibrosis.

Sclareol attenuates liver fibrosis through SENP1-mediated VEGFR2 SUMOylation and inhibition of downstream STAT3 signaling

Liver fibrosis is a key global health care burden. Sclareol, isolated from Salvia sclarea, possesses various biological activities. Its effect on liver fibrosis remains unknown. This study was proposed to evaluate the antifibrotic activity of sclareol (SCL) and explore its underlying mechanisms. Stimulated hepatic stellate cells served as an in vitro liver fibrosis model. The expression of fibrotic markers was assessed by western blot and real-time PCR. Two classical animal models, bile duct-ligated rats and carbon tetrachloride-treated mice, were utilized for the in vivo experiments. The liver function and fibrosis degree were determined by serum biochemical and histopathological analyses. VEGFR2 SUMOylation was analyzed using coimmunoprecipitation assay. Our results indicated that SCL treatment restricted the profibrotic propensity of activated HSCs. In fibrotic rodents, SCL administration alleviated hepatic injury and reduced collagen accumulation. Mechanistic studies indicated that SCL downregulated the protein level of SENP1 and enhanced VEGFR2 SUMOylation in LX-2 cells, which affected its intracellular trafficking. Blockade of the interaction between VEGFR2 and STAT3 was observed, resulting in the suppression of downstream STAT3 phosphorylation. Our findings demonstrated that SCL has therapeutic efficacy against liver fibrosis through mediating VEGFR2 SUMOylation, suggesting that SCL may be a potential candidate compound for its treatment.

Janus Silica Nanoparticle-Based Tumor Microenvironment Modulator for Restoring Tumor Sensitivity to Programmed Cell Death Ligand 1 Immune Checkpoint Blockade Therapy

An immunosuppressive tumor microenvironment (TME) with inadequate and exhausted tumor-infiltrating cytotoxic lymphocytes and abundant cellular immunosuppressors is the major obstacle responsible for the poor efficacy of PD-1/PD-L1 (programmed cell death 1 and its ligand 1) immune checkpoint blockade (ICB) therapy. Herein, a Janus silica nanoparticle (JSNP)-based immunomodulator is explored to reshape the TME for boosting the therapeutic outcomes of αPD-L1 therapy. The designed JSNP has two distinct domains, namely, an ultra pH-responsive side (UPS), which could encapsulate PI3Kγ inhibitor IPI549 in the pore structure, and a polycation-grafted intra-glutathione (GSH)-sensitive side (IGS), which could absorb CXCL9 cDNA on the surface. The final IPI549@UPS-IGS-PDMAEMA@CXCL9 cDNA (IUIPC) could release IPI549 in weak acid TME to target myeloid-derived suppressor cells (MDSCs) to reverse negative immunoregulation and then release CXCL9 cDNA in tumor cells with abundant GSH for sustained CXCL9 chemokine expression and secretion to improve cytotoxic lymphocyte recruitment signals, thereby jointly restoring tumor sensitivity to PD-1/PD-L1 ICB therapy. As expected, the IUIPC-mediated TME remodeling during αPD-L1 therapy significantly ameliorated TME immunosuppression, as well as induced potent systemic antitumor immune responses, which ultimately achieved a robustly boosted antitumor efficacy proven by remarkable suppression of primary tumor growth, obvious prevention of tumor recurrence, and significant regression of abscopal tumors. Hence, the IUIPC-mediated TME-regulating strategy provides an enormous perspective for the improvement of PD-1/PD-L1 ICB therapy.

Network Pharmacology and Molecular Docking Reveal the Mechanism of Isodon ternifolius (D. Don) Kudo Against Liver Fibrosis

Aim

Many studies have demonstrated the hepatoprotective or anti-fibrotic effects of Isodon ternifolius, but its pharmacological basis and mechanism remain unclear. In this study, we used in vitro models to validate the predicted results and revealed the potential mechanism of action and active ingredients through network pharmacology methods and molecular docking.

Methods

The chemical components of Isodon ternifolius were identified by literatures. Potential targets of Isodon ternifolius were predicted by Swiss Target Prediction. The disease targets were collected through the databases of Gene Card. Common targets of Isodon ternifolius and liver fibrosis were obtained by online tool Venny 2.1. PPI protein interaction network was obtained using String database, and target protein interaction network was drawn using Cytoscape software. Signaling pathway enrichment analysis was performed on drug-disease targets with of DAVID database.

Results

Twenty-one potential active ingredients and 298 potential targets were predicted by Swiss Target Prediction platform. Ninety pathways related to liver fibrosis were obtained by KEGG enrichment. The TLR4, MAPK and PI3K-Akt signaling pathways are mostly associated with liver fibrosis. Molecular docking techniques were used to validate the core target proteins TNF, Akt1, MAPK1, EGFR and TLR4 binding to the ingredients of Isodon ternifolius, which showed that a multitude of ingredients of Isodon ternifolius were able to bind to the above target proteins, especially 2α-hydroxy oleanolic acid and (-)-Lambertic acid. Our experimental validation results showed that Isodon ternifolius inhibited the activation of PI3K-Akt and ERK1/2 signaling pathways.

Conclusion

Through a network pharmacology approach and in vitro cell assay, we predicted and validated the active compounds of Isodon ternifolius and its potential targets for LF treatment. The results suggest that the mechanism of Isodon ternifolius treating LF by inhibiting angiogenesis may be related to the ERK1/2 and PI3K/Akt signaling pathways.

Serum CXCL5 Detects Early Hepatocellular Carcinoma and Indicates Tumor Progression

Chemokines or chemotactic cytokines play a pivotal role in the immune pathogenesis of liver cirrhosis and hepatocellular carcinoma (HCC). Nevertheless, comprehensive cytokine profiling data across different etiologies of liver diseases are lacking. Chemokines might serve as diagnostic and prognostic biomarkers. In our study, we analyzed serum concentrations of 12 inflammation-related chemokines in a cohort of patients (n = 222) with cirrhosis of different etiologies and/or HCC. We compared 97 patients with cirrhosis and treatment-naïve HCC to the chemokine profile of 125 patients with cirrhosis but confirmed absence of HCC. Nine out of twelve chemokines were significantly elevated in sera of cirrhotic patients with HCC compared to HCC-free cirrhosis controls (CCL2, CCL11, CCL17, CCL20, CXCL1, CXCL5, CXCL9, CXCL10, CXCL11). Among those, CXCL5, CXCL9, CXCL10, and CXCL11 were significantly elevated in patients with early HCC according to the Barcelona Clinic Liver Cancer (BCLC) stages 0/A compared to cirrhotic controls without HCC. In patients with HCC, CXCL5 serum levels were associated with tumor progression, and levels of CCL20 and CXCL8 with macrovascular invasion. Importantly, our study identified CXCL5, CXCL9, and CXCL10 as universal HCC markers, independent from underlying etiology of cirrhosis. In conclusion, regardless of the underlying liver disease, patients with cirrhosis share an HCC-specific chemokine profile. CXCL5 may serve as a diagnostic biomarker in cirrhotic patients for early HCC detection as well as for tumor progression.

Could senescence phenotypes strike the balance to promote tumor dormancy?

After treatment and surgery, patient tumors can initially respond followed by a rapid relapse, or respond well and seemingly be cured, but then recur years or decades later. The state of surviving cancer cells during the long, undetected period is termed dormancy. By definition, the dormant tumor cells do not proliferate to create a mass that is detectable or symptomatic, but also never die. An intrinsic state and microenvironment that are inhospitable to the tumor would bias toward cell death and complete eradication, while conditions that favor the tumor would enable growth and relapse. In neither case would clinical dormancy be observed. Normal cells and tumor cells can enter a state of cellular senescence after stress such as that caused by cancer therapy. Senescence is characterized by a stable cell cycle arrest mediated by chromatin modifications that cause gene expression changes and a secretory phenotype involving many cytokines and chemokines. Senescent cell phenotypes have been shown to be both tumor promoting and tumor suppressive. The balance of these opposing forces presents an attractive model to explain tumor dormancy: phenotypes of stable arrest and immune suppression could promote survival, while reversible epigenetic programs combined with cytokines and growth factors that promote angiogenesis, survival, and proliferation could initiate the emergence from dormancy. In this review, we examine the phenotypes that have been characterized in different normal and cancer cells made senescent by various stresses and how these might explain the characteristics of tumor dormancy.

CC group of chemokines and associated gene expression of transcription factors: Deciphering immuno-pathogenetic aspect of oral submucous fibrosis

BACKGROUND

Oral submucous fibrosis (OSMF) is a chronic disease with significantly increasing malignant transformation rate. To date the pathogenesis of OSMF has been considered to be associated with areca nut constituents and their action on fibroblasts. However, fibrosis is also associated with immunological factors such as chemokines. In-depth analysis of such factors is the need of the hour in OSMF to better understand the pathogenesis so that effective therapeutic strategies can be developed in the future.

MATERIALS AND METHOD

Clinically diagnosed cases of OSMF (n=21) and healthy individuals (n=10) were enrolled in the present study. Chemokines such as CCL2, CCL3, CCL4, CCL5, CCL11, CCL17, CCL28, CXCL1, CXCL5, CXCL8, CXCL9, CXCL10, and CXCL11 were assessed using the chemokine bead array in conjunction with the flow cytometry, along with real-time PCR (RT-PCR). The transcription factors CREB, NF-κB and NFAT5 were also studied for their expressions. The analysis of pg/ml (picogram/milliliter) values was done by using LEGENDplex™ Data Analysis Software.

RESULTS

The results obtained demonstrated early phase transient increase in CXCL-11, CCL20, CXCL9, CCL3, CCL2, CXCL10 and CXCL8. However, the expression of CCL3, CXCL10 and CXCL8 was higher in the late stage as compared to the early stage. The relative gene expression of CREB, NF-κB, NFAT5 were upregulated in the late stage of OSMF when compared to normal.

CONCLUSION

Distinctive sets of chemokine expression during the early and late stages of OSMF suggest a unique pattern of disease progression playing an important role in the pathogenesis.

12-O-tetradecanoylphorbol-13-acetate Reduces Activation of Hepatic Stellate Cells by Inhibiting the Hippo Pathway Transcriptional Coactivator YAP

Although protein kinase C (PKC) regulates various biological activities, including cell proliferation, differentiation, migration, tissue remodeling, gene expression, and cell death, the antifibrotic effect of PKC in myofibroblasts is not fully understood. We investigated whether 12-O-tetradecanoylphorbol-13-acetate (TPA), a PKC activator, reduced the activation of hepatic stellate cells (HSCs) and explored the involvement of the Hippo pathway transcriptional coactivator YAP. We analyzed the effect of TPA on the proliferation and expression of α-smooth muscle actin (SMA) in the LX-2 HSC line. We also analyzed the phosphorylation of the Hippo pathway molecules YAP and LATS1 and investigated YAP nuclear translocation. We examined whether Gö 6983, a pan-PKC inhibitor, restored the TPA-inhibited activities of HSCs. Administration of TPA decreased the growth rate of LX-2 cells and inhibited the expression of α-SMA and collagen type I alpha 1 (COL1A1). In addition, TPA induced phosphorylation of PKCδ, LATS1, and YAP and inhibited the nuclear translocation of YAP compared with the control. These TPA-induced phenomena were mostly ameliorated by Gö 6983. Our results indicate that PKCδ exerts an antifibrotic effect by inhibiting the Hippo pathway in HSCs. Therefore, PKCδ and YAP can be used as therapeutic targets for the treatment of fibrotic diseases.

Cyclin G2 in macrophages triggers CTL-mediated antitumor immunity and antiangiogenesis via interferon-gamma

BACKGROUND

IFN-γ is a key mediator of tumor immunity that can induce macrophage polarization to suppress tumor growth. Cyclin G2 functions as a tumor suppressor in various cancer cells; however, its role in macrophages remains unclear. This study aimed to investigate the role and underlying mechanisms of cyclin G2 in macrophages in vitro and in vivo.

METHODS

Mouse tumor models were used to determine the effect of cyclin G2 in macrophages on tumor growth in vivo following IFN-γ treatment. Immunohistochemistry staining, immunofluorescence staining and flow cytometry were used to evaluate the number of cytotoxic T lymphocytes (CTLs) and blood vessels in the mouse tumors. Moreover, the biological roles of cyclin G2 in macrophages with regard to CTL chemotaxis, cytotoxic function, and vascular endothelial cell tube formation were assessed using in vitro functional experiments. Immunoprecipitation (IP), real-time PCR, and enzyme-linked immunosorbent assays (ELISAs) were conducted to investigate the underlying mechanisms by which cyclin G2 regulates CTLs and vascular endothelial cells.

RESULTS

We found that cyclin G2 expression was upregulated in macrophages after IFN-γ treatment. Upregulated cyclin G2 inhibited lung and colon cancer growth by increasing the secretion of its downstream effector CXCL9, which promoted CTL chemotaxis and suppressed vascular endothelial cell tube formation. Moreover, cyclin G2 increased CXCL9 mRNA levels by promoting STAT1 nuclear translocation. In addition, cyclin G2 promoted the activation of the STAT1 signaling pathway, which was dependent on PP2Ac.

CONCLUSIONS

Cyclin G2 is upregulated by IFN-γ in macrophages, promotes the secretion of CXCL9 to increase CTL chemotaxis and inhibit angiogenesis to suppress tumor growth. Our findings suggest that targeting cyclin G2 could benefit future immunotherapy.

Biomechanical assessment of chronic liver injury using quantitative micro-elastography

Hepatocellular carcinoma is one of the most lethal cancers worldwide, causing almost 700,000 deaths annually. It mainly arises from cirrhosis, which, in turn, results from chronic injury to liver cells and corresponding fibrotic changes. Although it is known that chronic liver injury increases the elasticity of liver tissue, the role of increased elasticity of the microenvironment as a possible hepatocarcinogen is yet to be investigated. One reason for this is the paucity of imaging techniques capable of mapping the micro-scale elasticity variation in liver and correlating that with cancerous mechanisms on the cellular scale. The clinical techniques of ultrasound elastography and magnetic resonance elastography typically do not provide micro-scale resolution, while atomic force microscopy can only assess the elasticity of a limited number of cells. We propose quantitative micro-elastography (QME) for mapping the micro-scale elasticity of liver tissue into images known as micro-elastograms, and therefore, as a technique capable of correlating the micro-environment elasticity of tissue with cellular scale cancerous mechanisms in liver. We performed QME on 13 freshly excised healthy and diseased mouse livers and present micro-elastograms, together with co-registered histology, in four representative cases. Our results indicate a significant increase in the mean (×6.3) and standard deviation (×6.0) of elasticity caused by chronic liver injury and demonstrate that the onset and progression of pathological features such as fibrosis, hepatocyte damage, and immune cell infiltration correlate with localized variations in micro-elastograms.

A strategy of vascular-targeted therapy for liver fibrosis

BACKGROUND AND AIMS

No effective treatments are available for liver fibrosis. Angiogenesis is deeply involved in liver fibrogenesis. However, current controversial results suggest it is difficult to treat liver fibrosis through vascular targeting. There are three different microvessels in liver: portal vessels, liver sinusoids, and central vessels. The changes and roles for each of the three different vessels during liver fibrogenesis are unclear. We propose that they play different roles during liver fibrogenesis, and a single vascular endothelial cell (EC) regulator is not enough to fully regulate these three vessels to treat liver fibrosis. Therefore, a combined regulation of multiple different EC regulatory signaling pathway may provide new strategies for the liver fibrosis therapy. Herein, we present a proof-of-concept strategy by combining the regulation of leukocyte cell-derived chemotaxin 2 (LECT2)/tyrosine kinase with immunoglobulin-like and epidermal growth factor-like domains 1 signaling with that of vascular endothelial growth factor (VEGF)/recombinant VEGF (rVEGF) signaling.

APPROACH AND RESULTS

The CCl₄ -induced mouse liver fibrosis model and NASH model were both used. During fibrogenesis, vascular changes occurred at very early stage, and different liver vessels showed different changes and played different roles: decreased portal vessels, increased sinusoid capillarization and the increased central vessels the increase of portal vessels alleviates liver fibrosis, the increase of central vessels aggravates liver fibrosis, and the increase of sinusoid capillarization aggravates liver fibrosis. The combinational treatment of adeno-associated viral vector serotype 9 (AAV9)-LECT2-short hairpin RNA (shRNA) and rVEGF showed improved therapeutic effects, but it led to serious side effects. The combination of AAV9-LECT2-shRNA and bevacizumab showed both improved therapeutic effects and decreased side effects.

CONCLUSIONS

Liver vascular changes occurred at very early stage of fibrogenesis. Different vessels play different roles in liver fibrosis. The combinational treatment of AAV9-LECT2-shRNA and bevacizumab could significantly improve the therapeutic effects on liver fibrosis.

Altered TGFB1 regulated pathways promote accelerated tendon healing in the superhealer MRL/MpJ mouse

To better understand the molecular mechanisms of tendon healing, we investigated the Murphy Roth's Large (MRL) mouse, which is considered a model of mammalian tissue regeneration. We show that compared to C57Bl/6J (C57) mice, injured MRL tendons have reduced fibrotic adhesions and cellular proliferation, with accelerated improvements in biomechanical properties. RNA-seq analysis revealed that differentially expressed genes in the C57 healing tendon at 7 days post injury were functionally linked to fibrosis, immune system signaling and extracellular matrix (ECM) organization, while the differentially expressed genes in the MRL injured tendon were dominated by cell cycle pathways. These gene expression changes were associated with increased α-SMA+ myofibroblast and F4/80+ macrophage activation and abundant BCL-2 expression in the C57 injured tendons. Transcriptional analysis of upstream regulators using Ingenuity Pathway Analysis showed positive enrichment of TGFB1 in both C57 and MRL healing tendons, but with different downstream transcriptional effects. MRL tendons exhibited of cell cycle regulatory genes, with negative enrichment of the cell senescence-related regulators, compared to the positively-enriched inflammatory and fibrotic (ECM organization) pathways in the C57 tendons. Serum cytokine analysis revealed decreased levels of circulating senescence-associated circulatory proteins in response to injury in the MRL mice compared to the C57 mice. These data collectively demonstrate altered TGFB1 regulated inflammatory, fibrosis, and cell cycle pathways in flexor tendon repair in MRL mice, and could give cues to improved tendon healing.

XSSJS inhibits hepatic fibrosis by promoting the mir29b-3p/VEGFA axis in vitro and in vivo

Hepatic pathological angiogenesis (HPA) is the key event of hepatic fibrosis (HF). Xueshisanjia powder (XSSJS), a Chinese herbal compound, is beneficial for alleviating pathological angiogenesis of hepatic tissue. The present study attempts to reveal the effect and mechanism of XSSJS via regulating miR-29b-3p/VEGFA axis against pathological angiogenesis in HF. In in vitro model, human embryonic kidney 293T cells were transfected with miR-29b-3p mimics, whereby the expression of miR-29b-3p was tested by real-time quantitative polymerase chain reaction (RT-qPCR), ensued by Luciferase assay determining the relationship between miR-29b-3p and vascular endothelial cell growth factor A (VEGFA). In addition, miR-29b-3p mimic transfected into the activated hepatic stellate cell T6 (HSC-T6). The Cell-Counting-Kit 8 (CCK8) and 5-Bromodeoxyuridine (BrdU) staining were first utilized to detect the antiproliferative efficiency of XSSJS following the XSSJS compound serum intervention, and then used to observe the expression of transforming growth factor-β (TGF-β), VEGFA, platelet-derived growth factor (PDGF) via RT-PCR, Western blot (WB), and Immunofluorescence (IF) methods. During the in vivo model, XSSJS with boil-free granules were fed to Wistar rats with liver fibrosis caused by intraperitoneal injection of pig serum followed by the transfection of miR-29b-3p adeno-associated virus (AAV). Hematoxylin–Eosin (HE) staining was used for histopathology assessment. The expression of miR-29b-3p, VEGFA, PDGF, TGF-β have been investigated in liver tissue using RT-PCR, WB, IF. The results verified that XSSJS could up-regulate miR-29b-3p and suppress the expression of VEGFA, PDGA, and TGF-β. In mechanism, miR-29b-3p primarily targeted the 3′UTR of VEGFA. In conclusion, XSSJS could modulate miR-29b-3p/VEGFA axis to inhibit the pathological angiogenesis of HF.

Inhibition of renal fibrosis with a human CXCL9‐derived glycosaminoglycan‐binding peptide

Objectives

Renal fibrosis accompanies all chronic kidney disorders, ultimately leading to end‐stage kidney disease and the need for dialysis or even renal replacement. As such, renal fibrosis poses a major threat to global health and the search for effective therapeutic strategies to prevent or treat fibrosis is highly needed. We evaluated the applicability of a highly positively charged human peptide derived from the COOH‐terminal domain of the chemokine CXCL9, namely CXCL9(74–103), for therapeutic intervention. Because of its high density of net positive charges at physiological pH, CXCL9(74–103) competes with full‐length chemokines for glycosaminoglycan (GAG) binding. Consequently, CXCL9(74–103) prevents recruitment of inflammatory leucocytes to sites of inflammation.

Methods

CXCL9(74–103) was chemically synthesised and tested in vitro for anti‐fibrotic properties on human fibroblasts and in vivo in the unilateral ureteral obstruction (UUO) mouse model.

Results

CXCL9(74–103) significantly reduced the mRNA and/or protein expression of connective tissue growth factor (CTGF), alpha‐smooth muscle actin (α‐SMA) and collagen III by transforming growth factor (TGF)‐β1‐stimulated human fibroblasts. In addition, administration of CXCL9(74–103) inhibited fibroblast migration towards platelet‐derived growth factor (PDGF), without affecting cell viability. In the UUO model, CXCL9(74–103) treatment significantly decreased renal α‐SMA, vimentin, and fibronectin mRNA and protein expression. Compared with vehicle, CXCL9(74–103) attenuated mRNA expression of TGF‐β1 and the inflammatory markers/mediators MMP‐9, F4/80, CCL2, IL‐6 and TNF‐α. Finally, CXCL9(74–103) treatment resulted in reduced influx of leucocytes in the UUO model and preserved tubular morphology. The anti‐fibrotic and anti‐inflammatory effects of CXCL9(74–103) were mediated by competition with chemokines and growth factors for GAG binding.

Conclusions

Our findings provide a scientific rationale for targeting GAG–protein interactions in renal fibrotic disease.

Therapeutic potential of targeting regulatory mechanisms of hepatic stellate cell activation in liver fibrosis

Hepatic fibrosis is a manifestation of different etiologies of liver disease with the involvement of multiple mediators in complex network interactions. Activated hepatic stellate cells (aHSCs) are the central driver of hepatic fibrosis, given their potential to induce connective tissue formation and extracellular matrix (ECM) protein accumulation. Therefore, identifying the cellular and molecular pathways involved in the activation of HSCs is crucial in gaining mechanistic and therapeutic perspectives to more effectively target the disease. In addition to a comprehensive summary of our current understanding of the role of HSCs in liver fibrosis, we also discuss here the proposed therapeutic strategies based on targeting HSCs.

Therapeutic effects of CXCL9-overexpressing human umbilical cord mesenchymal stem cells on liver fibrosis in rats

Umbilical cord mesenchymal stem cells (UC-MSCs) transplantation has become a promising treatment for liver fibrosis. However, UC-MSCs have limited anti-fibrosis ability, and their homing ability of UC-MSCs to the injured liver seems to be poor. In our study, we aimed to determine if the CXCL9-overexpressing UC-MSCs could have synergistic anti-fibrosis effects and whether it can promote the homing ability of UC-MSCs. Overexpression of CXCL9 in UC-MSCs (CXCL9-UC-MSCs) was attained by transfecting the lenti-CXCL9-mCherry to naive UC-MSCs. The therapeutic effect of transducted CXCL9-UC-MSCs on both repairing of hepatic fibrosis and target homing were evaluated by comparing with the control of UC-MSCs transfected with empty lenti-mCherry vector. The results revealed that the liver function of CXCL9-UC-MSCs treated group was significantly improved when compared with that of control UC-MSCs (P < 0.05), and the histopathology indicated an obvious decrease of the collagen fiber content and significant disappearing of pseudo-lobules with basically normal morphology of hepatic lobules. Furthermore, liver frozen sections confirmed that CXCL9-UC-MSCs have significantly stronger chemotaxis and stable persistence in the injured liver tissues. In summary, overexpression of CXCL9 could improve the efficacy of UC-MSCs therapy for liver fibrosis repairing on account of an enhanced ability of UC-MSCs in homing to and staying in the injured sites of liver fibrosis in rat models.

Regulation and functional roles of chemokines in liver diseases

Inflammation is a major contributor to the pathogenesis of almost all liver diseases. Low-molecular-weight proteins called chemokines are the main drivers of liver infiltration by immune cells such as macrophages, neutrophils and others during an inflammatory response. During the past 25 years, tremendous progress has been made in understanding the regulation and functions of chemokines in the liver. This Review summarizes three main aspects of the latest advances in the study of chemokine function in liver diseases. First, we provide an overview of chemokine biology, with a particular focus on the genetic and epigenetic regulation of chemokine transcription as well as on the cell type-specific production of chemokines by liver cells and liver-associated immune cells. Second, we highlight the functional roles of chemokines in liver homeostasis and their involvement in progression to disease in both human and animal models. Third, we discuss the therapeutic opportunities targeting chemokine production and signalling in the treatment of liver diseases, such as alcohol-associated liver disease and nonalcoholic steatohepatitis, including the relevant preclinical studies and ongoing clinical trials.

Effects of blocking chemokine receptor CCR1 with BX471 in two models of fibrosis prevention and rescue in mice

Background

The induction, progression and resolution of liver fibrosis are influenced by multiple chemokines. The inhibition of CCR1 signalling by a specific non-peptide inhibitor (BX471) reduces kidney fibrosis after unilateral ureteral obstruction via suppression of leukocyte recruitment in mice. However, it remains unclear whether selective CCR1 inhibition also affects hepatic fibrogenesis. Therefore we aimed to study the effect of this intervention on liver fibrosis in prevention (CCl₄ administration) and rescue (ABCB4-deficient mice) mouse models.

Methods

In the prevention model, hepatic fibrosis was induced by repeated injections of CCl₄. Additionally, the verum group was treated with subcutaneous injections of BX471, while controls received vehicle only. ABCB4 deficient mice (on the BALB/c-background) with sclerosing cholangitis and biliary fibrosis received BX471 or vehicle, respectively (rescue model). Liver histopathology was assessed after Sirius red staining of collagen, and hepatic collagen contents were measured. In addition, we performed gene expression analyses of fibrosis-related genes.

Results

BX471 injections were tolerated moderately well by all mice, and all mice developed hepatic fibrosis. Significant differences were neither observed in serum aminotransferase activities after 6 weeks of treatment between the two groups in the prevention nor in the rescue model. Interestingly, hepatic collagen contents were significantly higher in mice treated with BX471 in the prevention model as compared to controls but histological stages of liver sections did not differ. Of note, we observed only moderate effects on liver fibrosis in the ABCB4 knock-out model.

Conclusions

Our data indicate that BX471 treatment did neither affect serum and tissue markers of liver injury and fibrosis in the CCl₄ model and only moderately in the Abcb4 ^-/- model of biliary fibrosis. The animal models indicate that treatment with BX471 alone is unlikely to exert major beneficial effects in chronic liver disease.

Inflammatory Mediators and Pain in Endometriosis: A Systematic Review

BACKGROUND

pain is one of the main symptoms of endometriosis and it has a deleterious effect on a patients' personal and social life. To date, the clinical management of pain includes prolonged medication use and, in some cases, surgery, both of which are disruptive events for patients. Hence, there is an urgency for the development of a sufficient non-invasive medical treatment. Inflammation is one of the causative factors of pain in endometriosis. It is well established that inflammatory mediators promote angiogenesis and interact with the sensory neurons inducing the pain signal; the threshold of pain varies and it depends on the state and location of the disease. The inhibition of inflammatory mediators' synthesis might offer a novel and effective treatment of the pain that is caused by inflammation in endometriosis.

OBJECTIVES

patients with endometriosis experience chronic pelvic pain, which is moderate to severe in terms of intensity. The objective of this systematic review is to highlight the inflammatory mediators that contribute to the induction of pain in endometriosis and present their biological mechanism of action. In addition, the authors aim to identify new targets for the development of novel treatments for chronic pelvic pain in patients with endometriosis.

DATA SOURCES

three databases (PubMed, Scopus, and Europe PMC) were searched in order to retrieve articles with the keywords 'inflammation, pain, and endometriosis' between the review period of 1 January 2016 to 31 December 2020. This review has been registered with PROSPERO (registry number: CRD42020171018). Eligibility Criteria: only original articles that presented the regulation of inflammatory mediators and related biological molecules in endometriosis and their contribution in the stimulation of pain signal were included.

DATA EXTRACTION

two authors independently extracted data from articles, using predefined criteria.

RESULTS

the database search yielded 1871 articles, which were narrowed down to 56 relevant articles of interest according to the eligibility criteria.

CONCLUSIONS

inflammatory factors that promote angiogenesis and neuroangiogenesis are promising targets for the treatment of inflammatory pain in endometriosis. Specifically, CXC chemokine family, chemokine fractalkine, and PGE2 have an active role in the induction of pain. Additionally, IL-1β appears to be the primary interleukin (IL), which stimulates the majority of the inflammatory factors that contribute to neuroangiogenesis along with IL-6. Finally, the role of Ninj1 and BDNF proteins needs further investigation.

Role of inflammatory chemokines in hypertension

Hypertension is associated with immune cells activation and their migration into the kidney, vasculature, heart and brain. These inflammatory mechanisms are critical for blood pressure regulation and mediate target organ damage, creating unique novel targets for pharmacological modulation. In response to angiotensin II and other pro-hypertensive stimuli, the expression of several inflammatory chemokines and their receptors is increased in the target organs, mediating homing of immune cells. In this review, we summarize the contribution of key inflammatory chemokines and their receptors to increased accumulation of immune cells in target organs and effects on vascular dysfunction, remodeling, oxidative stress and fibrosis, all of which contribute to blood pressure elevation. In particular, the role of CCL2, CCL5, CXCL8, CXCL9, CXCL10, CXCL11, CXCL16, CXCL1, CX3CL1, XCL1 and their receptors in the context of hypertension is discussed. Recent studies have tested the efficacy of pharmacological or genetic targeting of chemokines and their receptors on the development of hypertension. Promising results indicate that some of these pathways may serve as future therapeutic targets to improve blood pressure control and prevent target organ consequences including kidney failure, heart failure, atherosclerosis or cognitive impairment.

Immunity to acute virus infections with advanced age

New infections in general, and new viral infections amongst them, represent a serious challenge to an older organism. This review discusses the age-related alterations in responsiveness to infection from the standpoint of virus:host relationship and the host physiological whole-organism and specific immune response to the virus. Changes with age in the innate and adaptive immune system homeostasis and function are reviewed briefly. This is followed by a review of specific alterations and defects in the response of older organisms (chiefly mice and humans) to acute (particularly emerging and re-emerging) viral infections, with a very brief summary of the response to latent persistent infections. Finally, we provide a brief summary of the perspectives for possible interventions to enhance antiviral immunity.

Potential therapeutic manipulations of the CXCR3 chemokine axis for the treatment of inflammatory fibrosing diseases

Chemokines play important roles in homeostasis and inflammatory processes. While their roles in leukocyte recruitment are well-appreciated, chemokines play additional roles in the body, including mediating or regulating angiogenesis, tumor metastasis and wound healing. In this opinion article, we focus on the role of CXCR3 and its ligands in fibrotic processes. We emphasize differences of the effects of each ligand, CXCL9, CXCL10 and CXCL11, on fibroblasts in different tissues of the body. We include discussions of differences in signaling pathways that may account for protective or pro-fibrotic effects of each ligand in different experimental models and ex vivo analysis of human tissues. Our goal is to highlight potential reasons why there are disparate findings in different models, and to suggest ways in which this chemokine axis could be manipulated for the treatment of fibrosis.

CC motif chemokine ligand 16 inhibits the progression of liver cirrhosis via inactivating hepatic stellate cells

BACKGROUND

Liver cirrhosis results from many forms of chronic damage, characterized by accumulation of extracellular matrix. The present study aimed to explore a potential non-invasive biomarker and its mechanism in the progression of liver cirrhosis.

METHODS

Gene Expression Omnibus (GEO) dataset (GSE15654, n = 216) was analyzed to screen genes associated with progression of liver cirrhosis. A total of 181 plasma samples, including healthy control (HC, n = 20), chronic hepatitis B (CHB, n = 77) and HBV-related liver cirrhosis (LC, n = 84), were enrolled for validation. In vitro and in vivo experiments were employed for the mechanistic investigation.

RESULTS

GEO dataset analysis showed that relatively low mRNA-expression of CC motif chemokine ligand 16 (CCL16) was associated with elevated Child-Pugh score (P = 0.034) and worse prognosis (P = 0.025). Plasma CCL16 level decreased in a stepwise pattern, with a median concentration of 10.29, 6.57 and 4.47 ng/mL in the HC, CHB and LC groups, respectively (P<0.001). Low plasma CCL16 was significantly related to hepatic dysfunction both in the CHB and LC groups (P<0.05). Combination of CCL16 and ALT showed improved distinguishing capability for LC compared to either alone. In vitro, CCL16 expression was downregulated by lipopolysaccharide and hypoxia. Overexpression of CCL16 from human normal liver cell line (LO2) reduced the extracellular matrix associated proteins (Col1 and Col4) in human hepatic stellate cell line (LX-2). In vivo, the pathological feature of cirrhosis was alleviated by the hepatocyte-specific expression of CCL16.

CONCLUSIONS

CCL16 could be a feasible plasma marker to predict the occurrence and progression of liver cirrhosis. CCL16 might impact liver cirrhosis through inactivating hepatic stellate cells.

Progress in evaluating the status of hepatitis C infection based on the functional changes of hepatic stellate cells (Review)

Hepatitis C virus (HCV) infection is a global public health problem. Cirrhosis and hepatocellular carcinoma are the main causes of death in patients with chronic hepatitis C (CHC) infection. Liver fibrosis is an important cause of cirrhosis and end‑stage liver disease after CHC infection. Along with the course of infection, liver fibrosis exhibits a progressive exacerbation. Hepatic stellate cells (HSCs) are involved in both physiological and pathological processes of the liver. During the chronic liver injury process, the activated HSCs transform into myofibroblasts, which are important cells in the development of liver fibrosis. At present, HCV infection still lacks specific markers for the accurate detection of the disease condition and progression. Therefore, the present review focused on HSCs, which are closely related to HCV‑infected liver fibrosis, and analyzed the changes in the HSCs, including their surface‑specific markers, cytokine production, activation, cell function and morphological structure. The present review aimed to propose novel diagnostic markers, at both the cellular and molecular level, which would be of great significance for the timely diagnosis of the disease. According to this aim, the characteristic changes of HSCs during HCV infection were reviewed in the present article.

Kupffer cells promote T-cell hepatitis by producing CXCL10 and limiting liver sinusoidal endothelial cell permeability

Rationale: Kupffer cells (KCs) play a crucial role in liver immune homeostasis through interacting with other immune cells and liver sinusoidal endothelial cells (LSECs). However, how KCs exactly interact with these cells for maintaining the homeostasis still require the further investigation. CXCL10 is a chemokine that has been implicated in chemoattraction of monocytes, T cells, NK cells, and dendritic cells, and promotion of T cell adhesion to endothelial cells. Although CXCL10 is also known to participate in the pathogenesis of hepatic inflammation, the degree to which it is functionally involved in the crosstalk between immune cells and regulation of immune response is still unclear.

Methods: To dynamically investigate the function of KCs, we used our recently developed rapid cell ablation model, intermedilysin (ILY)/human CD59 (hCD59)-mediated cell ablation tool, to selectively ablate KC pool under normal condition or concanavalin A (Con A)- induced hepatitis. At certain time points after KCs ablation, we performed flow cytometry to monitor the amount of hepatic infiltrating immune cells. mRNA array was used to detect the change of hepatic cytokines and chemokines levels. Cytokines and chemokines in the serum were further measured by LEGENDplex^TM mouse proinflammatory chemokine panel and inflammation panel. Evans blue staining and transmission electron microscopy were used to investigate the interaction between KCs and LSECs in steady condition. CXCL10 neutralizing antibody and CXCL10 deficient mouse were used to study the role of CXCL10 in immune cell migration and pathogenesis of Con A-induced hepatitis.

Results: At steady state, elimination of KCs results in a reduction of hepatic infiltrating monocytes, T, B, and NK cells and a list of cytokines and chemokines at transcriptional level. In the meantime, the depletion of KCs resulted in increased sinusoidal vascular permeability. In the pathological condition, the KCs elimination rescues Con A-induced acute hepatitis through suppressing proinflammatory immune responses by down-regulation of hepatitis-associated cytokines/chemokines in serum such as CXCL10, and recruitment of infiltrating immune cells (monocytes, T, B, and NK cells). We further documented that deficiency or blockade of CXCL10 attenuated the development of Con A-induced hepatitis associated with reduction of the infiltrating monocytes, especially inflammatory Ly6C^hi monocytes.

Conclusions: This study supports the notion that KCs actively interact with immune cells and LSECs for maintaining immune response and liver homeostasis. Our data indicate that the interplay between KCs and infiltrated monocytes via CXCL10 contribute to Con A-induced hepatitis.

Plasminogen is a master regulator and a potential drug candidate for the healing of radiation wounds

Around 95% of cancer patients undergoing radiotherapy experience cutaneous side effects, and some develop radiation wounds or fibrosis. Currently, there is no effective treatment for these indications. We show here that plasminogen administration enhanced the healing of radiation wounds via pleiotropic effects on gene expression. Using RNA sequencing, we found that plasminogen downregulated the expression of genes in the TLR, TNF, WNT, MAPK, and TGF-β signaling pathways, and enhanced the anti-inflammatory effect of arachidonic acid, leading to significantly decreased inflammation and improved remodeling of granulation tissue compared with placebo treatment. In addition, plasminogen induced metabolic changes, including decreased glycolysis. Importantly, many of the factors downregulated by plasminogen are pro-fibrotic. Therefore, in radiation wounds with excessive inflammation, plasminogen is able to enhance and redirect the healing process, such that it more closely resembles physiological healing with significantly reduced risk for developing fibrosis. This makes plasminogen an attractive drug candidate for the treatment of radiation wounds in cancer patients.

Silencing lncRNA Lfar1 alleviates the classical activation and pyoptosis of macrophage in hepatic fibrosis

Hepatic fibrosis is a common pathological consequence of a sustained wound healing response to continuous liver injury, characterized by increased production and accumulation of extracellular matrix. If unresolved, the fibrotic process results in organ failure, and eventually death after the development of cirrhosis. It has been suggested that macrophages play central role in the progression of hepatic fibrosis, which is related to inflammation and pyroptosis, a novel programmed and proinflammatory cell death. However, it remains far less clear if, or how, lncRNAs regulates the activation and pyroptosis of macrophage in hepatic fibrosis. In the present study, we demonstrated that the liver-enriched lncRNA Lfar1, which has been reported to promote hepatic fibrosis through inducing hepatic stellate cells activation and hepatocytes apoptosis, was dysregulated during proinflammatory M1 activation and pyroptosis of macrophage. Our study revealed that silencing lnc-Lfar1 by a lentivirus-shRNA alleviated CCl₄- and BDL-induced proinflammatory M1 macrophage activation and NLRP3 inflammasome-mediated pyroptosis. Furthermore, the in vitro experiments demonstrated that lnc-Lfar1 knockdown significantly suppressed LPS- and IFN-γ-induced proinflammatory activation of macrophages, and inhibited LPS/ATP- and LPS/Nigericin-induced NLRP3 inflammasome-mediated pyroptosis. Mechanistically, lnc-Lfar1 regulated LPS- and IFN-γ-induced proinflammatory activation of macrophages through the NF-ĸB pathway. All these data supported our conclusion that lnc-Lfar1 plays a vital role in controlling the activation and pyroptosis of macrophage, thus providing a possible therapeutic target against inflammation-related disorders including hepatic fibrosis.

Inflammation and fibrosis in chronic liver diseases including non-alcoholic fatty liver disease and hepatitis C

At present chronic liver disease (CLD), the third commonest cause of premature death in the United Kingdom is detected late, when interventions are ineffective, resulting in considerable morbidity and mortality. Injury to the liver, the largest solid organ in the body, leads to a cascade of inflammatory events. Chronic inflammation leads to the activation of hepatic stellate cells that undergo trans-differentiation to become myofibroblasts, the main extra-cellular matrix producing cells in the liver; over time increased extra-cellular matrix production results in the formation of liver fibrosis. Although fibrogenesis may be viewed as having evolved as a “wound healing” process that preserves tissue integrity, sustained chronic fibrosis can become pathogenic culminating in CLD, cirrhosis and its associated complications. As the reference standard for detecting liver fibrosis, liver biopsy, is invasive and has an associated morbidity, the diagnostic assessment of CLD by non-invasive testing is attractive. Accordingly, in this review the mechanisms by which liver inflammation and fibrosis develop in chronic liver diseases are explored to identify appropriate and meaningful diagnostic targets for clinical practice. Due to differing disease prevalence and treatment efficacy, disease specific diagnostic targets are required to optimally manage individual CLDs such as non-alcoholic fatty liver disease and chronic hepatitis C infection. To facilitate this, a review of the pathogenesis of both conditions is also conducted. Finally, the evidence for hepatic fibrosis regression and the mechanisms by which this occurs are discussed, including the current use of antifibrotic therapy.

Fuzhenghuayu Decoction ameliorates hepatic fibrosis by attenuating experimental sinusoidal capillarization and liver angiogenesis

Fuzhenghuayu (FZHY) is a compound extracted from natural plants. Its anti-fibrotic effect has been confirmed in experimental and clinical studies. However, precise effects and underlying mechanisms of FZHY in liver angiogenesis largely remain understood. In this study, we investigated the effects of FZHY on sinusoidal capillarization and angiogenesis with mice challenged for Carbon tetrachloride (CCl₄) and dimethylnitrosamine (DMN), in vitro human hepatic sinusoidal endothelial cells (HHSEC) and Human Umbilical Vein Endothelial Cell (HUVEC) 3D fibrin gel model. Besides its anti-fibrotic effect, FZHY ameliorated CCl₄ and DMN-induced sinusoidal capillarization, angiogenesis and expression of angiogenesis-associated factors, i.e. CD31, VEGF, VEGF receptor II, phosphor-ERK and HIF-1α. Consistent with the findings based on animal models, inhibitory effects of FZHY on capillarization and angiogenesis were further confirmed in HHSEC and the HUVEC 3D fibrin gel model, respectively. These data suggest that FZHY ameliorates not only liver fibrosis but also vessel remodeling in experimental models. Therefore, FZHY might be a potentially useful drug to treat liver cirrhosis in clinical practice.

Expression of vascular endothelial growth factor A in liver tissues of infants with biliary atresia

Aim of the study

Assessment of hepatic expression of vascular endothelial growth factor A (VEGF-A) in liver tissues of infants with biliary atresia (BA).

Material and methods

This retrospective study included 35 infants with BA (BA group), and 38 infants with cholestasis due to causes other than BA (non-BA group). All patients had undergone full history taking, through clinical examination, routine investigations and immunostaining of liver tissue for VEGF-A and cytokeratin 7 (CK7). The diagnosis of BA was confirmed by intraoperative cholangiography. In the non-BA group, other specific laboratory tests according to the expected etiology were done.

Results

Most of the BA group showed positive VEGF-A expression with variable degrees in both bile ducts (BDs; 80%), and arterial walls (AWs; 77.2%), while most of the non-BA group showed negative staining of VEGF in both BDs and AWs (89.5% and 86.8% respectively) (p < 0.0001). Positive VEGF expression in the portal structures in both BDs and AWs had 84.9% and 82.19% accuracy; respectively. The majority of BA group showed either grade II of positive cytokeratin-7 expression in liver tissues (45.7%) or grade III (34.3%), while most of the non-BA group showed grade I (71.1%) (p < 0.0001). Positive CK7 expression in > 25% of the liver tissues had 80.8% accuracy in discriminating between BA and non-BA.

Conclusions

VEGF-A expression in the portal structures in liver tissues in both BDs and AWs had very good accuracy in discriminating between BA and non-BA patients.

The Chemokine Receptor CXCR3 Isoform B Drives Breast Cancer Stem Cells

We are seeking to identify molecular targets that are relevant to breast cancer cells with stem-like properties. There is growing evidence that cancer stem cells (CSCs) are supported by inflammatory mediators expressed in the tumor microenvironment. The chemokine receptor CXCR3 binds the interferon-γ-inducible, ELR-negative CXC chemokines CXCL9, CXCL10, and CXCL11 and malignant cells have co-opted this receptor to promote tumor cell migration and invasion. There are 2 major isoforms of CXCR3: CXCR3A and CXCR3B. The latter is generated from alternative splicing and results in a protein with a longer N-terminal domain. CXCR3 isoform A is generally considered to play a major role in tumor metastasis. When the entire tumor cell population is examined, CXCR3 isoform B is usually detected at much lower levels than CXCR3A and for this, and other reasons, was not considered to drive tumor progression. We have shown that CXCR3B is significantly upregulated in the subpopulation of breast CSCs in comparison with the bulk tumor cell population in 3 independent breast cancer cell lines (MDA-MB-231, SUM159, and T47D). Modulation of CXCR3B levels by knock in strategies increases CSC populations identified by aldehyde dehydrogenase activity or CD44⁺CD24⁻ phenotype as well as tumorsphere-forming capacity. The reverse is seen when CXCR3B is gene-silenced. CXCL11 and CXCL10 directly induce CSC. We also report that novel CXCR3 allosteric modulators BD064 and BD103 prevent the induction of CSCs. BD103 inhibited experimental metastasis. This protective effect is associated with the reversal of CXCR3 ligand-mediated activation of STAT3, ERK1/2, CREB, and NOTCH1 pathways. We propose that CXCR3B, expressed on CSC, should be explored further as a novel therapeutic target.

Inhibiting expression of Cxcl9 promotes angiogenesis in MSCs-HUVECs co-culture

The insufficient vascularization is a major challenge in bone tissue engineering, leading to partial necrosis of the implant. Pre-vascularization is a promising way via in vitro cells co-culture strategies using osteogenic cells and vasculogenic cells, and the cross-talk of cells is essential. In the present study, the effect of rat bone-marrow derived mesenchymal stem cells (BMSCs) on angiogenic capability of human umbilical vein endothelial cells (HUVECs) in growth medium (GM) and osteogenic induction medium (OIM) was investigated. It was demonstrated that cells co-cultured in OIM showed high efficiency in osteogenesis but failed to form capillary-like structure while the results of co-culture in GM were the opposite. By comparing the angiogenic capacity of co-cultures under GM and OIM, chemokine (C-X-C motif) ligand 9 (Cxcl9), secreted by BMSCs in OIM, was identified to be an angiostatic factor to counter-regulate vascular endothelial growth factor (VEGF) and prevent its binding to HUVECs, which abrogated angiogenesis of MSCs-ECs co-culture. Moreover, Cxcl9 was proved to suppress the osteogenic differentiation of BMSCs monoculture. The molecular mechanism of Cxcl9 activation in BMSCs involved mTOR/STAT1 signaling pathway. Therefore, blocking this signaling pathway via rapamycin addition resulted in the inhibition of Cxcl9 and improvement of osteogenic differentiation and angiogenic capacity of co-culture in OIM. These results reveal that Cxcl9 is a negative modulator of angiogenesis and osteogenesis, and its inhibition could promote pre-vascularization of bone tissue engineering.

Rapamycin improves bone mass in high-turnover osteoporosis with iron accumulation through positive effects on osteogenesis and angiogenesis

Iron accumulation is an independent risk factor for type I osteoporosis, but the molecular mechanisms of the phenomenon are not well defined, and effective therapy has not been reported. Here, we found that the level of mTOR was increased both in wild-type mouse models with iron accumulation and transgenic mouse models (Hepc^-/-) of high-turnover osteoporosis with iron accumulation. We show that an increased level of mTOR can depress osteogenesis and angiogenesis by Cxcl9 both in bone and in vitro. Suppression of mTOR in mouse models by rapamycin and in vitro by siRNA transfection recovered both osteogenesis and angiogenesis. These findings revealed the role of mTOR in osteogenesis and angiogenesis in high-turnover osteoporosis with iron accumulation and showed that rapamycin targeting of mTOR ameliorates osteogenesis and angiogenesis to improve bone mass.

Targeting Endothelial Erk1/2-Akt Axis as a Regeneration Strategy to Bypass Fibrosis during Chronic Liver Injury in Mice

Liver sinusoidal endothelial cells (LSECs) have great capacity for liver regeneration, and this capacity can easily switch to profibrotic phenotype, which is still poorly understood. In this study, we elucidated a potential target in LSECs for regenerative treatment that can bypass fibrosis during chronic liver injury. Proregenerative LSECs can be transformed to profibrotic phenotype after 4 weeks of carbon tetrachloride administration or 10 days of bile duct ligation. This phenotypic alternation of LSECs was mediated by extracellular regulated protein kinases 1 and 2 (Erk1/2)-Akt axis switch in LSECs during chronic liver injury; Erk1/2 was normally associated with maintenance of the LSEC proregenerative phenotype, inhibiting hepatic stellate cell (HSC) activation and promoting tissue repair by enhancing nitric oxide (NO)/reactive oxygen species (ROS) ratio and increasing expression of hepatic growth factor (HGF) and Wingless-type MMTV integration site family member 2 (Wnt2). Alternatively, Akt induced LSEC profibrotic phenotype, which mainly stimulated HSC activation and concomitant senescence by reducing NO/ROS ratio and decreasing HGF/Wnt2 expression. LSEC-targeted adenovirus or drug particle to promote Erk1/2 activity can alleviate liver fibrosis, accelerate fibrosis resolution, and enhance liver regeneration. This study demonstrated that the Erk1/2-Akt axis acted as a switch to regulate the proregenerative and profibrotic phenotypes of LSECs, and targeted therapy promoted liver regeneration while bypassing fibrosis, providing clues for a more effective treatment of liver diseases.

Gene expression profiling of human hepatocytes grown on differing substrate stiffness

OBJECTIVE

To study the effects of different substrate stiffness on human hepatocytes using RNA sequencing (RNA-Seq) technology. The stiffness was corresponding to physiology and pathology stiffness of liver tissues.

RESULTS

With the aid of RNA-Seq technology, our study characterizes the transcriptome of hepatocytes cultured on soft, moderate, stiff and plastic substrates. Compared to soft substrate, our RNA-Seq results revealed 1131 genes that were up-regulated and 2534 that were down-regulated on moderate substrate, 1370 genes that were up-regulated and 2677 down-regulated genes on stiff substrate. Functional enrichment analysis indicated that differentially expressed genes were associated with the regulation of actin cytoskeleton, focal adhesion, tight junction, adherens junction as well as antigen processing and presentation. RNA-Seq results were further verified by a quantitative real-time reverse transcriptase polymerase chain reaction.

CONCLUSION

Our study provides a comprehensive picture of the gene expression landscape in hepatocytes grown on different substrate stiffness, offering insights into the role of substrate stiffness in hepatic pathology.

Angiogenesis: Managing the Culprits behind Tumorigenesis and Metastasis

Deregulated angiogenesis has been identified as a key contributor in a number of pathological conditions including cancer. It is a complex process, which involves highly regulated interaction of multiple signalling molecules. The pro-angiogenic signalling molecule, vascular endothelial growth factor (VEGF) and its cognate receptor 2 (VEGFR-2), which is often highly expressed in majority of human cancers, plays a central role in tumour angiogenesis. Owing to the importance of tumour vasculature in carcinogenesis, tumour blood vessels have emerged as an excellent therapeutic target. The anti-angiogenic therapies have been shown to arrest growth of solid tumours through multiple mechanisms, halting the expansion of tumour vasculature and transient normalization of tumour vasculature which help in the improvement of blood flow resulting in more uniform delivery of cytotoxic agents to the core of tumour mass. This also helps in reduction of hypoxia and interstitial pressure leading to reduced chemotherapy resistance and more uniform delivery of cytotoxic agents at the targeted site. Thus, complimentary combination of different agents that target multiple molecules in the angiogenic cascade may optimize inhibition of angiogenesis and improve clinical benefit in the cancer patients. This review provides an update on the current trend in exploitation of angiogenesis pathways as a strategy in the treatment of cancer.

Overview of the Mechanisms that May Contribute to the Non-Redundant Activities of Interferon-Inducible CXC Chemokine Receptor 3 Ligands

The inflammatory chemokines CXCL9, CXCL10, and CXCL11 are predominantly induced by interferon (IFN)-γ and share an exclusive chemokine receptor named CXC chemokine receptor 3 (CXCR3). With a prototype function of directing temporal and spatial migration of activated T cells and natural killer cells, and inhibitory effects on angiogenesis, these CXCR3 ligands have been implicated in infection, acute inflammation, autoinflammation and autoimmunity, as well as in cancer. Intense former research efforts led to recent and ongoing clinical trials using CXCR3 and CXCR3 ligand targeting molecules. Scientific evidence has claimed mutual redundancy, ligand dominance, collaboration or even antagonism, depending on the (patho)physiological context. Most research on their in vivo activity, however, illustrates that CXCL9, CXCL10, and CXCL11 each contribute to the activation and trafficking of CXCR3 expressing cells in a non-redundant manner. When looking into detail, one can unravel a multistep machinery behind final CXCR3 ligand functions. Not only can specific cell types secrete individual CXCR3 interacting chemokines in response to certain stimuli, but also the receptor and glycosaminoglycan interactions, major associated intracellular pathways and susceptibility to processing by particular enzymes, among others, seem ligand-specific. Here, we overview major aspects of the molecular properties and regulatory mechanisms of IFN-induced CXCR3 ligands, and propose that their in vivo non-redundancy is a reflection of the unprecedented degree of versatility that seems inherent to the IFN-related CXCR3 chemokine system.