The heavy subunit of ferritin stimulates NLRP3 inflammasomes in hepatic stellate cells through ICAM-1 to drive hepatic inflammation.

Serum ferritin concentrations increase during hepatic inflammation and correlate with the severity of chronic liver disease. Here, we report a molecular mechanism whereby the heavy subunit of ferritin (FTH) contributes to hepatic inflammation. We found that FTH induced activation of the NLRP3 inflammasome and secretion of the proinflammatory cytokine interleukin-1ß (IL-1ß) in primary rat hepatic stellate cells (HSCs) through intercellular adhesion molecule-1 (ICAM-1). FTH-ICAM-1 stimulated the expression of Il1b, NLRP3 inflammasome activation, and the processing and secretion of IL-1ß in a manner that depended on plasma membrane remodeling, clathrin-mediated endocytosis, and lysosomal destabilization. FTH-ICAM-1 signaling at early endosomes stimulated Il1b expression, implying that this endosomal signaling primed inflammasome activation in HSCs. In contrast, lysosomal destabilization was required for FTH-induced IL-1ß secretion, suggesting that lysosomal damage activated inflammasomes. FTH induced IL-1ß production in liver slices from wild-type mice but not in those from Icam1-/- or Nlrp3-/- mice. Thus, FTH signals through its receptor ICAM-1 on HSCs to activate the NLRP3 inflammasome. We speculate that this pathway contributes to hepatic inflammation, a key process that stimulates hepatic fibrogenesis associated with chronic liver disease.

Exploring the impact of severity in hepatic fibrosis disease on the intrahepatic distribution of novel biodegradable nanoparticles targeted towards different disease biomarkers.

Nanoparticle-based drug delivery systems (DDS) have shown promising results in reversing hepatic fibrosis, a common pathological basis of chronic liver diseases (CLDs), in preclinical animal models. However, none of these nanoparticle formulations has transitioned to clinical usage and there are currently no FDA-approved drugs available for liver fibrosis. This highlights the need for a better understanding of the challenges faced by nanoparticles in this complex disease setting. Here, we have systematically studied the impact of targeting strategy, the degree of macrophage infiltration during fibrosis, and the severity of fibrosis, on the liver uptake and intrahepatic distribution of nanocarriers. When tested in mice with advanced liver fibrosis, we demonstrated that the targeting ligand density plays a significant role in determining the uptake and retention of the nanoparticles in the fibrotic liver whilst the type of targeting ligand modulates the trafficking of these nanoparticles into the cell population of interest - activated hepatic stellate cells (aHSCs). Engineering the targeting strategy indeed reduced the uptake of nanoparticles in typical mononuclear phagocyte (MPS) cell populations, but not the infiltrated macrophages. Meanwhile, additional functionalization may be required to enhance the efficacy of DDS in end-stage fibrosis/cirrhosis compared to early stages.

The ancestral haplotype markers HLA -A3 and B7 do not influence the likelihood of advanced hepatic fibrosis or cirrhosis in HFE hemochromatosis.

Advanced hepatic fibrosis occurs in up to 25% of individuals with C282Y homozygous hemochromatosis. Our aim was to determine whether human leukocyte antigen (HLA)-A3 and B7 alleles act as genetic modifiers of the likelihood of advanced hepatic fibrosis. Between 1972 and 2013, 133 HFE C282Y homozygous individuals underwent clinical and biochemical evaluation, HLA typing, liver biopsy for fibrosis staging and phlebotomy treatment. Hepatic fibrosis was graded according to Scheuer as F0-2 (low grade hepatic fibrosis), F3-4 (advanced hepatic fibrosis), and F4 cirrhosis. We analysed associations between the severity of fibrosis and HLA-A3 homozygosity, heterozygosity or absence, with or without the presence of HLA-B7 using categorical analysis. The mean age of HLA-A3 homozygotes (n = 24), heterozygotes (n = 65) and HLA-A3 null individuals (n = 44) was 40 years. There were no significant differences between the groups for mean(± SEM) serum ferritin levels (1320 ± 296, 1217 ± 124, 1348 ± 188 [Formula: see text]g/L), hepatic iron concentration (178 ± 26, 213 ± 22, 199 ± 29 [Formula: see text]mol/g), mobilizable iron stores (9.9 ± 1.5, 9.5 ± 1.5, 11.5 ± 1.7 g iron removed via phlebotomy), frequency of advanced hepatic fibrosis (5/24[12%], 13/63[19%], 10/42[19%]) or cirrhosis (3/24[21%], 12/63[21%], 4/42[24%]), respectively. The presence or absence of HLA-B7 did not influence the outcome. Thus, HLA-A3 and HLA-B7 alleles are not associated with the risk of advanced hepatic fibrosis or cirrhosis in C282Y hemochromatosis.

Single-nucleus RNA sequencing of pre-malignant liver reveals disease-associated hepatocyte state with HCC prognostic potential.

Current approaches to staging chronic liver diseases have limited utility for predicting liver cancer risk. Here, we employed single-nucleus RNA sequencing (snRNA-seq) to characterize the cellular microenvironment of healthy and pre-malignant livers using two distinct mouse models. Downstream analyses unraveled a previously uncharacterized disease-associated hepatocyte (daHep) transcriptional state. These cells were absent in healthy livers but increasingly prevalent as chronic liver disease progressed. Copy number variation (CNV) analysis of microdissected tissue demonstrated that daHep-enriched regions are riddled with structural variants, suggesting these cells represent a pre-malignant intermediary. Integrated analysis of three recent human snRNA-seq datasets confirmed the presence of a similar phenotype in human chronic liver disease and further supported its enhanced mutational burden. Importantly, we show that high daHep levels precede carcinogenesis and predict a higher risk of hepatocellular carcinoma development. These findings may change the way chronic liver disease patients are staged, surveilled, and risk stratified.

Risk factors for more rapid progression of severe liver fibrosis in children with cystic fibrosis-related liver disease: A multi-center study validated by liver biopsy.

BACKGROUND AND AIMS: Early identification of risk factors for the development of severe fibrosis in children with cystic fibrosis-related liver disease (CFLD) is crucial as promising therapies emerge. METHODS: This multi-center cohort study of children with a priori defined CFLD from 1999 to 2016, was designed to evaluate the clinical utility of CF-specific characteristics and liver biomarkers assessed years prior to liver biopsy-proven CFLD to predict risk of developing severe fibrosis (F3-4) over time. Fibrosis was staged by Metavir classification. RESULTS: The overall study cohort of 42 patients (F0-2 (n = 22) and F3-4 (n = 20)) was 57% male (n = 24) with median age of 7.6 years at baseline visit versus 10.3 years at biopsy. Median FEV1 % predicted was lower in F3-4 participants at baseline versus F0-2 (59% vs. 85%; p = .002), while baseline FIB-4, APRI and GGT were higher in F3-4. Median splits for FIB-4 (≥.13), APRI (≥.36), GPR (≥.09), GGT (≥25.5), and FEV1 % (<64%) were associated with more rapid progression to F3-4 (p < .01 for all). Using a combination of change/year in FIB-4, APRI, and GPR to predict F3-4, the AUROC was .81 (95% CI, .66, .96; p < .0001). For up to 5.8 years prior, thresholds for GPR were met 6.5-fold more rapidly, and those for APRI and FIB-4 were met 2.5-fold more rapidly, in those who progressed to F3-4 than those that did not. CONCLUSIONS: This study suggests mild-moderate pulmonary dysfunction and higher liver biomarker indices at baseline may be associated with faster progression of CFLD.

TWEAK/Fn14 Signalling Regulates the Tissue Microenvironment in Chronic Pancreatitis.

Chronic pancreatitis increases the risk of developing pancreatic cancer through the upregulation of pathways favouring proliferation, fibrosis, and sustained inflammation. We established in previous studies that the ligand tumour necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) signals through its cognate receptor fibroblast growth factor-inducible 14 (Fn14) to regulate these underlying cellular processes in the chronic liver injury niche. However, the role of the TWEAK/Fn14 signalling pathway in pancreatic disease is entirely unknown. An analysis of publicly available datasets demonstrated that the TWEAK receptor Fn14 is upregulated in pancreatitis and pancreatic adenocarcinoma, with single cell RNA sequencing revealing pancreatic ductal cells as the main Fn14 producers. We then used choline-deficient, ethionine-supplemented (CDE) diet feeding of wildtype C57BL/6J and Fn14 knockout littermates to (a) confirm CDE treatment as a suitable model of chronic pancreatitis and (b) to investigate the role of the TWEAK/Fn14 signalling pathway in pancreatic ductal proliferation, as well as fibrotic and inflammatory cell dynamics. Our time course data obtained at three days, three months, and six months of CDE treatment reveal that a lack of TWEAK/Fn14 signalling significantly inhibits the establishment and progression of the tissue microenvironment in CDE-induced chronic pancreatitis, thus proposing the TWEAK/Fn14 pathway as a novel therapeutic target.

Characterization of CFTR mutations in people with cystic fibrosis and severe liver disease who are not eligible for CFTR modulators.

Cystic-fibrosis-related liver disease (CFLD) is a variable phenotype of CF. The severe CFLD variant with cirrhosis or portal hypertension has a poor prognosis and life expectancy. CFTR modulator therapies are now available for people with CF and eligibility for such treatment is based on their CFTR genotype. We evaluated the genetic eligibility for elexacaftor, tezacaftor, ivacaftor (ETI), and ivacaftor (IVA) monotherapy in a previously reported CF cohort of 1591 people with CF of whom 171 with severe CFLD. Based on their CFTR mutations, 13% (N=184/1420) of subjects without CFLD and 11% (N=19/171) of those with severe CFLD are not eligible for either ETI or IVA therapy. The non-eligible patients without CFLD or with severe CFLD can currently not take advantage of the potential benefits of these new treatments. Although this study cannot provide any data regarding the effect of ETI or IVA on the progression of severe CFLD, the consequences for ineligibility of patients with extreme liver phenotype may be even more significant because of their poorer disease risk profile.

The structural conformation of the tachykinin domain drives the anti-tumoural activity of an octopus peptide in melanoma BRAFV600E.

BACKGROUND AND PURPOSE: Over past decades, targeted therapies and immunotherapy have improved survival and reduced the morbidity of patients with BRAF-mutated melanoma. However, drug resistance and relapse hinder overall success. Therefore, there is an urgent need for novel compounds with therapeutic efficacy against BRAF-melanoma. This prompted us to investigate the antiproliferative profile of a tachykinin-peptide from the Octopus kaurna, Octpep-1 in melanoma. EXPERIMENTAL APPROACH: We evaluated the cytotoxicity of Octpep-1 by MTT assay. Mechanistic insights on viability and cellular damage caused by Octpep-1 were gained via flow cytometry and bioenergetics. Structural and pharmacological characterization was conducted by molecular modelling, molecular biology, CRISPR/Cas9 technology, high-throughput mRNA and calcium flux analysis. In vivo efficacy was validated in two independent xerograph animal models (mice and zebrafish). KEY RESULTS: Octpep-1 selectively reduced the proliferative capacity of human melanoma BRAFV600E -mutated cells with minimal effects on fibroblasts. In melanoma-treated cells, Octpep-1 increased ROS with unaltered mitochondrial membrane potential and promoted non-mitochondrial and mitochondrial respiration with inefficient ATP coupling. Molecular modelling revealed that the cytotoxicity of Octpep-1 depends upon the α-helix and polyproline conformation in the C-terminal region of the peptide. A truncated form of the C-terminal end of Octpep-1 displayed enhanced potency and efficacy against melanoma. Octpep-1 reduced the progression of tumours in xenograft melanoma mice and zebrafish. CONCLUSION AND IMPLICATIONS: We unravel the intrinsic anti-tumoural properties of a tachykinin peptide. This peptide mediates the selective cytotoxicity in BRAF-mutated melanoma in vitro and prevents tumour progression in vivo, providing a foundation for a therapy against melanoma.

Arthritis Prediction of Advanced Hepatic Fibrosis in HFE Hemochromatosis.

OBJECTIVE: To evaluate whether arthritis predicts the likelihood of advanced hepatic fibrosis in HFE hemochromatosis. PATIENTS AND METHODS: We conducted a retrospective, cross-sectional analysis of 112 well-characterized patients with HFE hemochromatosis and liver biopsy-validated fibrosis staging recruited between January 1, 1983, and December 31, 2013. Complete clinical, biochemical, hematologic, and noninvasive serum biochemical indices (aspartate aminotransferase to platelet ratio index [APRI] and fibrosis 4 index [FIB4]) were available. Scheuer fibrosis stages 3 and 4, APRI greater than 0.44, or FIB4 greater than 1.1 were used to define advanced hepatic fibrosis. Comparisons between groups were performed using categorical analysis, unpaired or paired t test. RESULTS: Male (n=76) and female (n=36) patients were similar in age. Nineteen patients had advanced hepatic fibrosis, and 47 had hemochromatosis arthritis. Arthritis was significantly associated with the presence of advanced hepatic fibrosis as determined by liver biopsy (sensitivity, 84%, [95% CI, 62% to 95%]; negative predictive value, 95% [95% CI, 87% to 99%]; relative risk, 7.4 [95% CI, 2.5 to 23]; P<.001), APRI (sensitivity, 75% [95% CI, 55% to 88%]; negative predictive value, 91% [95% CI, 81% to 96%]; relative risk, 4.5 [95% CI, 2.0 to 10.2]; P<.001), or FIB4 (sensitivity, 61% [95% CI, 41% to 78%]; negative predictive value, 67% [95% CI, 68% to 90%]; relative risk, 2.2 [95% CI, 1.1 to 4.6]; P=.03). Mean cell volume values were significantly higher pretreatment in patients with F3-4 fibrosis (96.7±1.1 fL) compared with F0-2 fibrosis (93.4±0.5 fL; P=.004) and declined following treatment (F3-4, 93.2±0.9 fL, P=.01; F0-2, 91.7±0.6 fL, P=.01). CONCLUSION: Advanced hepatic fibrosis is strongly associated with arthritis in HFE hemochromatosis. The absence of arthritis predicts a low likelihood of advanced hepatic fibrosis, supporting its use as a clinical marker for advanced hepatic fibrosis in HFE hemochromatosis.

Synthetic peptides derived from the Schistosoma mansoni secretory protein Sm16 induce contrasting responses in hepatic stellate cells.

Sm16 is a 16 KDa protein released by Schistosoma mansoni that modulates inflammatory responses in host cells. Sm16 is expressed by several life cycle stages of S. mansoni, including the egg stage. Schistosome eggs are known to provoke chronic schistosomiasis pathology, which involves the development of liver fibrosis. Hepatic stellate cells (HSCs), which are responsible for this fibrosis, are susceptible to immunomodulation by S. mansoni whole egg secretions. To define the effects of Sm16 exposure on HSCs, two synthetic peptide derivatives of Sm16, coined "KS-84″ and "KS-66″, were tested against LX-2 cells, an immortalised human HSC line, and RNA sequencing was used to assess the transcriptional changes induced by each peptide. In total, 78 and 798 genes were found to be significantly differentially expressed by KS-84 and KS-66 treatment, respectively. In silico pathway analysis of these genes revealed that KS-84 reduced LX-2 cell activation and fibrotic potential, whereas KS-66 increased both processes. Reduced transforming growth factor-ß1 (TGF-ß1) signalling was identified as a potential mechanism of KS-84-induced inhibition of LX-2 activation. Taken together, these findings indicate a potential role for Sm16 in combatting fibrotic liver disease.

Therapeutic potential of macrophage colony-stimulating factor in chronic liver disease.

Resident and recruited macrophages control the development and proliferation of the liver. We have previously shown in multiple species that treatment with a macrophage colony stimulating factor (CSF1)-Fc fusion protein initiated hepatocyte proliferation and promoted repair in models of acute hepatic injury in mice. Here, we investigated the impact of CSF1-Fc on resolution of advanced fibrosis and liver regeneration, using a non-resolving toxin-induced model of chronic liver injury and fibrosis in C57BL/6J mice. Co-administration of CSF1-Fc with exposure to thioacetamide (TAA) exacerbated inflammation consistent with monocyte contributions to initiation of pathology. After removal of TAA, either acute or chronic CSF1-Fc treatment promoted liver growth, prevented progression and promoted resolution of fibrosis. Acute CSF1-Fc treatment was also anti-fibrotic and pro-regenerative in a model of partial hepatectomy in mice with established fibrosis. The beneficial impacts of CSF1-Fc treatment were associated with monocyte-macrophage recruitment and increased expression of remodelling enzymes and growth factors. These studies indicate that CSF1-dependent macrophages contribute to both initiation and resolution of fibrotic injury and that CSF1-Fc has therapeutic potential in human liver disease.

Advanced but not mild liver disease is a predictor of decreased survival in children with cystic fibrosis, with far greater impact in females: A 27-year real-life cohort study.

BACKGROUND: Improved survival of children with CF has increased our need to understand the relevance of cystic fibrosis-associated liver disease (CFLD). We assessed the impact of liver disease and disease severity on the survival of children with cystic fibrosis. METHODS: A real life, single center cohort study with 27 years follow up was conducted. Mild CFLD was diagnosed as children with abnormal serum liver function tests and abnormal ultrasound. Advanced CFLD was established by detection of cirrhosis or portal hypertension. A directed acyclic graph, Kaplan-Meier (KM) and Cox regression analysis were used to model survival. RESULTS: 290 patients were enrolled, 48 (16.5%) had mild CFLD and 55 (19%) had advanced CFLD. Ten children with advanced CFLD and 1 with mild CFLD died. Based on the KM analysis, the mean (SE) overall survival age of all CF children was 29.1 years (0.50). The mean (SE) survival among females with advanced CFLD was 24.7 years (1.58) compared to 30.4 years (0.66) for females without advanced CFLD (p = 0.0027). Advanced CFLD was a predictor of decreased survival when adjusted for sex and diabetes (HR 2.54, 95%CI 1.05-6.15, p = 0.039). Mild CFLD was not associated with decreased survival. The effect of advanced CFLD on survival was mainly borne by females (HR = 6.37, 95%CI 1.62-25.06 vs. males, HR = 1.00, 95%CI 0.25-4.01). CONCLUSION: Advanced but not mild CFLD was associated with an increased risk of death when adjusted for sex and diabetes, and resulted in premature death in females with cystic fibrosis by approximately 6 years.

Gamma-glutamyl transpeptidase-to-platelet ratio as a biomarker of liver disease and hepatic fibrosis severity in paediatric Cystic Fibrosis.

BACKGROUND: Cystic fibrosis (CF)-associated liver disease (CFLD) causes significant morbidity and mortality in children with CF. Diagnosis of liver disease prior to development of cirrhosis or portal hypertension (PHT) is challenging. While imaging modalities using Elastography show great promise they are still not widely available to all clinicians. This study investigated gamma-glutamyl transpeptidase-to-platelet ratio (GPR) as a non-invasive biomarker to detect liver disease and stage fibrosis severity in children with CF. METHODS: 237 children were enroled including 76 with CFLD and 161 with CF and no detectable liver disease (CFnoLD). CFLD was diagnosed using standard clinical, biochemical and imaging practice guidelines. Hepatic fibrosis was staged on liver biopsies available from 54 children with CFLD. Serum liver biochemistry was used to calculate GPR (median, [IQR]) and receiver operating characteristics (ROC) analysis assessed utility to detect liver disease and stage fibrosis severity. RESULTS: GPR was significantly increased in CFLD versus CFnoLD (0.33 [0.19-0.96] vs. 0.15 [0.11-0.21], P<0.0001). GPR demonstrated good diagnostic utility for detecting CFLD with an area under the curve (AUC) of 0.81 (95% confidence Interval [CI] [0.75-0.87]; P<0.0001), with sensitivity of 74% and specificity of 73%, using a cut-off of 0.20. GPR increased with increasing hepatic fibrosis stage. GPR discriminated both moderate-advanced (F2-F4) fibrosis vs. F0-F1 (AUC=0.82; 95%CI [0.71-0.94]; P<0.0001) and advanced (F3-F4) fibrosis vs. F0-F2 (AUC=0.77; 95%CI [0.64-0.90]; P = 0.004), with a cut-off 0.32 and 0.61, respectively. An elevated GPR of >0.84 was predictive of PHT at diagnosis of CFLD (AUC=0.81; 95%CI [0.67-0.95]; P = 0.0003). CONCLUSIONS: GPR demonstrates good diagnostic utility for assessing the presence of liver disease, PHT and hepatic fibrosis severity in children with CF. These findings will aid in better identification of patients at risk for CF-related liver involvement and the potential for more targeted and timely follow-up and treatment.

Ursodeoxycholic acid and liver disease associated with cystic fibrosis: A multicenter cohort study.

BACKGROUND: The efficacy and safety of ursodeoxycholic acid (UDCA) for the treatment of liver disease associated with cystic fibrosis (CF) are under discussion, and clinical practice varies among centers. The study aimed at evaluating if the incidence of severe liver disease differs between CF centers routinely prescribing or not prescribing UDCA. METHODS: We carried out a retrospective multicenter cohort study including 1591 CF patients (1192 patients from UDCA-prescribing centers and 399 from non-prescribing centers) born between 1990 and 2007 and followed from birth up to 31 December 2016. We computed the crude cumulative incidence (CCI) of portal hypertension (PH) at the age of 20 years in the two groups and estimated the subdistribution hazard ratio (HR) through a Fine and Gray model. RESULTS: Over the observation period, 114 patients developed PH: 90 (7.6%) patients followed-up in UDCA prescribing centers and 24 (6.0%) in non-prescribing centers. The CCI of PH at 20 years was 10.1% (95% CI: 7.9-12.3) in UDCA-prescribing and 7.7% (95% CI: 4.6-10.7) in non-prescribing centers. The HR among patients followed in prescribing centers indicated no significant difference in the rate of PH either in the unadjusted model (HR: 1.21, 95% CI: 0.69-2.11) or in the model adjusted for pancreatic insufficiency (HR: 1.28, 95% CI: 0.77-2.12). CONCLUSIONS: CF patients followed-up in UDCA prescribing centers did not show a lower incidence of PH as compared to those followed in centers not prescribing UDCA. These results question the utility of UDCA in reducing the occurrence of severe liver disease in CF.

Cost-Effectiveness of a Serum Biomarker Test for Risk-Stratified Liver Ultrasound Screening for Hepatocellular Carcinoma.

OBJECTIVES: Risk-stratified ultrasound screening for hepatocellular carcinoma (HCC), informed by a serum biomarker test, enables resources to be targeted to patients at the highest risk of developing cancer. We aimed to investigate the cost-effectiveness of risk-stratified screening for HCC in the Australian healthcare system. METHODS: A Markov cohort model was constructed to test 3 scenarios for patients with compensated cirrhosis: (1) risk-stratified screening for high-risk patients, (2) all-inclusive screening, and (3) no formal screening. Probabilistic sensitivity analyses were undertaken to determine the impact of uncertainty. Scenario analyses were used to assess cost-effectiveness in Australia's Aboriginal and Torres Strait Islander peoples and to determine the impact of including productivity-related costs of mortality. RESULTS: Both risk-stratified screening and all-inclusive screening programs were cost-effective compared with no formal screening, with incremental cost-effectiveness ratios of A$39 045 and A$23 090 per quality-adjusted life-year (QALY), respectively. All-inclusive screening had an incremental cost-effectiveness ratio of A$4453 compared with risk-stratified screening and had the highest probability of being cost-effective at a willingness-to-pay (WTP) threshold of A$50 000 per QALY. Risk-stratified screening had the highest likelihood of cost-effectiveness when the WTP was between A$25 000 and A$35 000 per QALY. Cost-effectiveness results were further strengthened when applied to an Aboriginal and Torres Strait Islander cohort and when productivity costs were included. CONCLUSIONS: Cirrhosis population-wide screening for HCC is likely to be cost-effective in Australia. Risk-stratified screening using a serum biomarker test may be cost-effective at lower WTP thresholds.

RNA sequencing of LX-2 cells treated with TGF-ß1 identifies genes associated with hepatic stellate cell activation.

BACKGROUND: Hepatic stellate cells (HSCs) are liver-resident myofibroblast precursors responsible for the production of collagen and maintenance of the hepatic extracellular matrix (ECM). As such, they are generally associated with fibrotic liver diseases. HSCs become "activated" in response to tissue damage or pathogen invasion, a process most commonly driven by transforming growth factor-ß1 (TGF-ß1). Despite this, the full extent of TGF-ß1 signalling in these cells is poorly understood. Clarifying the range and diversity of this signalling will further improve our understanding of the process of HSC activation. METHODS AND RESULTS: RNA sequencing was used to quantitate the transcriptomic changes induced in LX-2 cells, an activated human HSC line, following TGF-b1 treatment. In total, 5,258 genes were found to be significantly differentially expressed with a false discovery rate cut-off of < 0.1. The topmost deregulated of these genes included those with no currently characterised role in either HSC activation or fibrotic processes, including CIITA and SERPINB2. In silico analysis revealed the prominent signalling pathways downstream of TGF-ß1 in LX-2 cells. CONCLUSIONS: In this study, we describe the genes and signalling pathways significantly deregulated in LX-2 cells following TGF-ß1 treatment. We identified several highly deregulated genes with no currently characterised role in HSC activation, which may represent novel mediators of fibrotic responses in HSCs or the liver macroenvironment. This work may be of use in the identification of new markers of liver fibrosis and could provide insight into prospective genes or pathways that might be targeted for the amelioration of fibrotic liver disease in the future.

The Role of Sonic Hedgehog in Human Holoprosencephaly and Short-Rib Polydactyly Syndromes.

The Hedgehog (HH) signalling pathway is one of the major pathways controlling cell differentiation and proliferation during human development. This pathway is complex, with HH function influenced by inhibitors, promotors, interactions with other signalling pathways, and non-genetic and cellular factors. Many aspects of this pathway are not yet clarified. The main features of Sonic Hedgehog (SHH) signalling are discussed in relation to its function in human development. The possible role of SHH will be considered using examples of holoprosencephaly and short-rib polydactyly (SRP) syndromes. In these syndromes, there is wide variability in phenotype even with the same genetic mutation, so that other factors must influence the outcome. SHH mutations were the first identified genetic causes of holoprosencephaly, but many other genes and environmental factors can cause malformations in the holoprosencephaly spectrum. Many patients with SRP have genetic defects affecting primary cilia, structures found on most mammalian cells which are thought to be necessary for canonical HH signal transduction. Although SHH signalling is affected in both these genetic conditions, there is little overlap in phenotype. Possible explanations will be canvassed, using data from published human and animal studies. Implications for the understanding of SHH signalling in humans will be discussed.