PPAR-Gamma Orchestrates EMT, AGE, and Cellular Senescence Pathways in Colonic Epithelium and Restrains the Progression of IBDs

Intestinal fibrosis, the most common complication of inflammatory bowel disease (IBD), is characterized by an uncontrolled deposition of extracellular matrix proteins leading to complications resolvable only with surgery. Transforming growth factor is the key player in the epithelial-mesenchymal transition (EMT) and fibrogenesis process, and some molecules modulating its activity, including peroxisome proliferator-activated receptor (PPAR)-γ and its agonists, exert a promising antifibrotic action. The purpose of this study is to evaluate the contribution of signaling other than EMT, such as the AGE/RAGE (advanced glycation end products/receptor of AGEs) and the senescence pathways, in the etiopathogenesis of IBD. We used human biopsies from control and IBD patients, and we used a mouse model of colitis induced by dextran-sodium-sulfate (DSS), without/with treatments with GED (PPAR-gamma-agonist), or 5-aminosalicylic acid (5-ASA), a reference drug for IBD treatment. In patients, we found an increase in EMT markers, AGE/RAGE, and senescence signaling activation compared to controls. Consistently, we found the overexpression of the same pathways in DSS-treated mice. Surprisingly, the GED reduced all the pro-fibrotic pathways, in some circumstances more efficiently than 5-ASA. Results suggest that IBD patients could benefit from a combined pharmacological treatment targeting simultaneously different pathways involved in pro-fibrotic signals. In this scenario, PPAR-gamma activation could be a suitable strategy to alleviate the signs and symptoms of IBD and also its progression.

Is mastocytic colitis a specific clinical-pathological entity?

The number of intestinal mast cells (MC) is increased in several types of colitis, but the mucosa of patients with chronic non-bloody diarrhea has not been studied. The current study sought to determine the relationship between MC counts and degranulation and the severity of symptoms in patients with chronic loose stools. Following a negative laboratory workup for the most common causes of chronic diarrhea, patients with chronic non-bloody loose stools were included in the study. Patients with macroscopic evidence of inflammation or organic disease were excluded after endoscopy with biopsies. Biopsies from the 179 patients in the study were stained with hematoxylin and eosin and anti-CD117 c-kit antibodies. Immunohistochemistry was used to assess the degree of MC degranulation. Out of the 179 patients, 128 had normal histologic findings suggestive of irritable bowel syndrome and were used as controls. Twenty-four presented with abnormally high MC counts (≥40 MC x HPF), 23 with ≥20 intraepithelial lymphocytes x HPF suggesting lymphocytic colitis, and 4 had both (≥40 MC and ≥20 intraepithelial lymphocytes x HPF). In the patients with high MC counts, figures were significantly higher in the right colon versus the left colon (p=0.016), but degranulation did not differ in the right versus the left colon (p=0.125). No age or sex-related difference was observed (p=0.527 and p=0.859 respectively). The prevalence of abdominal pain and bloating did not differ in the three groups (p=0.959 and p=0.140, respectively). Patients with lymphocytic colitis (p=0.008) and those with high MC counts (p=0.025) had significantly higher evacuation rates compared to controls. There was no difference between these two groups (p=0.831). Mast cell degranulation was not associated with the number of evacuations, abdominal pain, or bloating (p=0.51; p=0.41; p=0.42, respectively). The finding that a significantly higher number of evacuations was linked to increased MC in the colonic mucosa of a subset of patients with otherwise normal laboratory and endoscopic findings suggests that "mastocytic colitis" may be a new clinical-pathological entity responsible for chronic non-bloody diarrhea. Prospective studies with a larger number of patients, as well as endoscopic and histological follow-up, are needed to confirm this hypothesis.

Extracellular Vesicles and Resistance to Anticancer Drugs: A Tumor Skeleton Key for Unhinging Chemotherapies

Although surgical procedures and clinical care allow reaching high success in fighting most tumors, cancer is still a formidable foe. Recurrence and metastatization dampen the patients’ overall survival after the first diagnosis; nevertheless, the large knowledge of the molecular bases drives these aspects. Chemoresistance is tightly linked to these features and is mainly responsible for the failure of cancer eradication, leaving patients without a crucial medical strategy. Many pathways have been elucidated to trigger insensitiveness to drugs, generally associated with the promotion of tumor growth, aggressiveness, and metastatisation. The main mechanisms reported are the expression of transporter proteins, the induction or mutations of oncogenes and transcription factors, the alteration in genomic or mitochondrial DNA, the triggering of autophagy or epithelial-to-mesenchymal transition, the acquisition of a stem phenotype, and the activation of tumor microenvironment cells. Extracellular vesicles (EVs) can directly transfer or epigenetically induce to a target cell the molecular machinery responsible for the acquisition of resistance to drugs. In this review, we resume the main body of knowledge supporting the crucial role of EVs in the context of chemoresistance, with a particular emphasis on the mechanisms related to some of the main drugs used to fight cancer.

Ferroptosis resistance cooperates with cellular senescence in the overt stage of nonalcoholic fatty liver disease/nonalcoholic steatohepatitis

Cellular senescence and ferroptosis are the two main, fine-tuned processes in tissue damage restraint; however, they can be overactivated in pathologies such as nonalcoholic fatty liver disease/nonalcoholic steatohepatitis (NAFLD/NASH), becoming dangerous stimuli. Senescence is characterized by a decline in cell division and an abnormal release of reactive oxygen species (ROS), and ferroptosis is represented by iron deposition associated with an excessive accumulation of ROS. ROS and cellular stress pathways are also drivers of NAFLD/NASH development. The etiology of NAFLD/NASH lies in poor diets enriched in fat and sugar. This food regimen leads to liver steatosis, resulting in progressive degeneration of the organ, with a late onset of irreversible fibrosis and cirrhosis. Few studies have investigated the possible connection between senescence and ferroptosis in NAFLD/NASH progression, despite the two events sharing some molecular players. We hypothesized a possible link between senescence and ferroptosis in a NAFLD background. To thoroughly investigate this in the context of "Western-style" diet (WSD) abuse, we used an amylin-modified liver NASH mouse model. The main NASH hallmarks have been confirmed in this model, as well as an increase in apoptosis, and Ki67 and p53 expression in the liver. Senescent beta-galactosidase-positive cells were elevated, as well as the expression of the related secretory molecules Il-6 and MMP-1. Features of DNA damage and iron-overload were found in the livers of NASH mice. Gpx4 (glutathione peroxidase 4) expression, counteracting ferroptotic cell death, was increased. Notably, an increased number of senescent cells showing overexpression of gpx4 was also found. Our data seem to suggest that senescent cells acquire a gpx4-mediated mechanism of ferroptosis resistance and thus remain in the liver, fostering the deterioration of liver fitness.

The antiinflammatory and antifibrotic effect of olive phenols and Lactiplantibacillus plantarum IMC513 in dextran sodium sulfate-induced chronic colitis

OBJECTIVES

After a chronic intestinal injury, several intestinal cells switch their phenotype to activated myofibroblasts, which in turn release an abnormal amount of extracellular matrix proteins, leading to the onset of the fibrotic process. To date, no resolutive pharmacological treatments are available, and the identification of new therapeutic approaches represents a crucial goal to achieve. The onset, maintenance, and progression of inflammatory bowel disease are related to abnormal intestinal immune responses to environmental factors, including diet and intestinal microflora components. This study aimed to evaluate the potential antiinflammatory and antifibrotic effect of a biologically debittered olive cream and its probiotic oral administration in an experimental model of dextran sodium sulfate (DSS)-induced chronic colitis.

METHODS

Chronic colitis was induced in mice by three cycles of oral administration of 2.5% DSS (5 d of DSS followed by 7 d of tap water). Mice were randomly divided into five groups: 10 control mice fed with standard diet (SD), 20 mice receiving SD and DSS (SD+DSS), 20 mice receiving an enriched diet (ED) with olive cream and DSS (ED+DSS), 20 mice receiving SD plus probiotics (PB; Lactiplantibacillus plantarum IMC513) and DSS (SD+PB+DSS), and 20 mice receiving ED plus PB and DSS (ED+ PB+DSS). Clinical features and large bowel macroscopic, histologic, and immunohistochemical findings were evaluated.

RESULTS

The simultaneous administration of ED and PB induced a significant reduction in macroscopic and microscopic colitis scores compared with the other DSS-treated groups. In addition, ED and PB led to a significant decrease in the expression of inflammatory cytokines and profibrotic molecules.

CONCLUSIONS

The concomitant oral administration of a diet enriched with biologically debittered olive cream and a specific probiotic strain (Lactiplantibacillus plantarum IMC513) can exert synergistic antiinflammatory and antifibrotic action in DSS-induced chronic colitis. Further studies are needed to define the cellular and molecular mechanisms modulated by olive cream compounds and by Lactiplantibacillus plantarum IMC513.

Prolonged Chronic Consumption of a High Fat with Sucrose Diet Alters the Morphology of the Small Intestine

(1) The high-fat diet (HFD) of western countries has dramatic effect on the health of several organs, including the digestive tract, leading to the accumulation of fats that can also trigger a chronic inflammatory process, such as that which occurs in non-alcohol steatohepatitis. The effects of a HFD on the small intestine, the organ involved in the absorption of this class of nutrients, are still poorly investigated. (2) To address this aspect, we administered a combined HFD with sucrose (HFD w/Suc, fat: 58% Kcal) regimen (18 months) to mice and investigated the morphological and molecular changes that occurred in the wall of proximal tract of the small intestine compared to the intestine of mice fed with a standard diet (SD) (fat: 18% Kcal). (3) We found an accumulation of lipid droplets in the mucosa of HFD w/Suc-fed mice that led to a disarrangement of mucosa architecture. Furthermore, we assessed the expression of several key players involved in lipid metabolism and inflammation, such as perilipin, leptin, leptin receptor, PI3K, p-mTOR, p-Akt, and TNF-α. All these molecules were increased in HFD mice compared to the SD group. We also evaluated anti-inflammatory molecules like adiponectin, adiponectin receptor, and PPAR-γ, and observed their significant reduction in the HFD w/Suc group compared to the control. Our data are in line with the knowledge that improper eating habits present a primary harmful assault on the bowel and the entire body's health. (4) These results represent a promising starting point for future studies, helping to better understand the complex and not fully elucidated spectrum of intestinal alterations induced by the overconsumption of fat.

The Charming World of the Extracellular Matrix: A Dynamic and Protective Network of the Intestinal Wall

The intestinal extracellular matrix (ECM) represents a complex network of proteins that not only forms a support structure for resident cells but also interacts closely with them by modulating their phenotypes and functions. More than 300 molecules have been identified, each of them with unique biochemical properties and exclusive biological functions. ECM components not only provide a scaffold for the tissue but also afford tensile strength and limit overstretch of the organ. The ECM holds water, ensures suitable hydration of the tissue, and participates in a selective barrier to the external environment. ECM-to-cells interaction is crucial for morphogenesis and cell differentiation, proliferation, and apoptosis. The ECM is a dynamic and multifunctional structure. The ECM is constantly renewed and remodeled by coordinated action among ECM-producing cells, degrading enzymes, and their specific inhibitors. During this process, several growth factors are released in the ECM, and they, in turn, modulate the deposition of new ECM. In this review, we describe the main components and functions of intestinal ECM and we discuss their role in maintaining the structure and function of the intestinal barrier. Achieving complete knowledge of the ECM world is an important goal to understand the mechanisms leading to the onset and the progression of several intestinal diseases related to alterations in ECM remodeling.

Long-term abuse of a high-carbohydrate diet is as harmful as a high-fat diet for development and progression of liver injury in a mouse model of NAFLD/NASH

OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) has become the most common liver disease globally. It is caused by a complex network of factors, including diet. The hallmark of NAFLD is the benign accumulation of triacylglycerols, however, this condition may worsen into non-alcoholic steatohepatitis (NASH), a more severe form associated with inflammation and fibrosis. Currently, no therapies are available, and diet modifications are the only strategy. Although there is increasing evidence emerging about how an abuse of carbohydrates could be involved in the progression of liver injury, a comprehensive understanding of the damage induced by an enriched carbohydrate diet is still far from complete. The aim of this study was to investigate and compare the effects of a low-fat/high-carbohydrate diet (LF-HCD) with high-fat (HFD) and standard (SD) diets in a nutritional mouse model of NAFLD/NASH.

METHODS

Histologic, real-time polymerase chain reaction, and immunohistochemical evaluations were performed.

RESULTS

The results showed that the prolonged abuse of both LF-HCDs and HFDs induced a significant increase in hepatic steatosis, inflammation, and fibrosis scores compared with SD. At the same time, both LF-HCDs and HFDs led to significant increases in the expression of the molecules involved in the progression of NAFLD that we assessed (perilipin, CD68, TGF-β1, CTGF, leptin, leptin receptor, and α-SMA).

CONCLUSIONS

The present study highlighted that the simple substitution of fats with carbohydrates is not a proper strategy to prevent or mitigate the progression of NAFLD/NASH. Further studies are required to define the best nutritional strategy to prevent NAFLD and its related metabolic syndrome.

Can the AGE/RAGE/ERK signalling pathway and the epithelial-to-mesenchymal transition interact in the pathogenesis of chronic rhinosinusitis with nasal polyps?

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a persistent sinonasal mucosa inflammatory disease with still unclear pathophysiologic mechanisms that imply events of tissue repair and structural remodelling. Several cascades seem to have a considerable role in the onset and progression of mucosa hyperproliferation in nasal polyps including transforming growth factor β/Small mother against decapentaplegic (TGFβ/Smads), mitogenactivated protein kinases (MAPKs), advanced glycosylation end-products (AGEs) together with epithelial-tomesenchymal transition (EMT). Since many inflammatory mediators are reported to play important roles in the development of nasal polyps (NP) disease, this study aimed to analyse the correlation between the AGEs/receptor of advanced glycosylation end-products (RAGE)/extracellular signal-regulated kinase (ERK) signalling pathway and the main markers of EMT to better understand the influence that they exert on the remodelling of nasal mucous membranes in patients affected by CRSwNP vs normal controls. A total of 30 patients were enrolled in this study. Immunohistochemical analysis, using AGE, RAGE, p-ERK, MMP-3, TGF-β1, Smad2/3, Collagen I-III, α-SMA, E-cadherin, IL-6 and Vimentin antibodies, was performed. AGE, RAGE, ERK, p-ERK and MMP3 were also evaluated using western blot analysis. We observed an overexpression of the AGE/RAGE/p-ERK and the main mesenchymal markers of EMT (Vimentin and IL-6) in CRSwNP vs controls whereas the TGF-β/Smad3 pathway did not show any significant differences between the two groups of patients. These observations suggest a complex network of processes in the pathogenesis of NP, and the AGE/RAGE/ERK pathway and EMT might work together in promoting tissue remodelling in the formation of CRSwNP.

PPAR-γ with its anti-inflammatory and anti-fibrotic action could be an effective therapeutic target in IBD

OBJECTIVE

Intestinal fibrosis is a process characterized by an excessive deposition of Extracellular Matrix (ECM) proteins by activated myofibroblasts and represents a consequence of a chronic inflammation that usually occurs during Inflammatory Bowel Disease (IBD). The relationship between inflammation and fibrosis in IBD remains still unclear and nevertheless the recent pharmacological progresses, currently the only resolutive therapeutic strategy is surgery, especially when complications (stricture, stenosis and obstruction of intestinal tracts) appear. As many different cellular types and molecular mechanisms are implicated in the pathogenesis of IBD, the identification of molecules able to counteract this process could be crucial.

MATERIALS AND METHODS

This is a literature review of several articles published on PubMed databases.

RESULTS

A number of researches suggest that Proliferator-Activated Receptor-gamma (PPAR-γ) has both anti-inflammatory and anti-fibrotic effects in many organs. PPAR-γ has been demonstrated to be able to downregulate pro-inflammatory cytokines production such as Interleukin (IL)-4,-5,-6 but also to interfere with profibrotic molecules as Platelet-Derived Growth Factor (PDGF), IL-1 and Transforming Growth Factor Beta (TGF-β), the main promoter of fibrosis. In preliminary clinical trials and in experimental models of intestinal fibrosis, natural and chemical PPAR-γ ligands have ameliorated the fibrotic process.

CONCLUSIONS

Since PPAR-γ could play a crucial role in the development of the disease, the research of new molecules, capable of ameliorating both inflammation and fibrosis lesions, as PPAR-γ agonists, could represent a valid and effective therapeutic approach for the prevention and treatment of IBD and intestinal fibrosis.

Neurovascular alterations of muscularis propria in the human anterior vaginal wall in pelvic organ prolapse

In the pathophysiology and progression of pelvic organ prolapse (POP), it has been demonstrated that there is a reorganisation of the muscularis propria of the anterior vaginal wall due to a phenotypic smooth muscle cell to myofibroblast switch. An abnormal deposition of collagen type III seems to be influenced by the involvement of advanced glycation end‐products. The aim of the present study was to evaluate the hypothesis that this connective tissue remodelling could also be associated with neurovascular alterations of the muscularis in women with POP compared with control patients. We examined 30 women with POP and 10 control patients treated for uterine fibromatosis. Immunohistochemical analysis, using glial fibrillary acidic protein, S‐100 protein, receptor tyrosine kinase, neurofilament and α‐smooth muscle actin antibodies, was performed. S‐100, receptor tyrosine kinase and neurofilament were also evaluated using Western blot analysis. We observed a decrease in all neurovascular‐tested markers in nerve bundles, ganglia and interstitial cells of Cajal from POP samples as compared with controls. Even if the processes responsible for these morphological alterations are still not known, it is conceivable that collagen III deposition in the anterior vaginal wall affects not only the architecture of the muscle layer but could also modify the intramuscular neurovascularisation and account for an alteration of the neuromuscular plasticity of the layer.

Epidermal growth factor-like domain multiple 7 (EGFL7): Expression and possible effect on biliary epithelium growth in cholangiocarcinoma

Cholangiocarcinoma (CCA) is an aggressive biliary tract malignancy with limited treatment options and low survival rates. The intrahepatic subtype comprises two forms: mucin-iCCA and mixed-iCCA. Epidermal growth factor-like domain multiple (EGFL7) is overexpressed in less differentiated liver tumors. The aim of this study was to assess the presence of EGFL7 due to its possible role in the growth of CCA. Hematoxylin & Eosin and periodic acid- Schiff staining were used to evaluate the morphological aspects and glycogen deposition. Immunohistochemistry and immunofluorescence were performed to identify the presence of EGFL7 both in tumor sections ex vivo and in appropriate cell lines in culture. We found that EGFL7 is expressed in malignant cholangiocytes of mixed-iCCA and absent in mucin-iCCA. In conclusion the expression of EGFL7 might be useful in the classification of CCA subtypes.

Interaction between sphingosine kinase/sphingosine 1 phosphate and transforming growth factor-β/Smads pathways in experimental intestinal fibrosis. An in vivo immunohistochemical study

A concomitant action of multiple profibrotic mediators appears crucial in the development and progression of fibrosis. Sphingosine kinase/sphingosine 1 phosphate and transforming growth factor- β/Smads pathways are both involved in pathogenesis of fibrosis in several organs by controlling differentiation of fibroblasts to myofibroblasts and the epithelial-to-mesenchymal transition. However, their direct involvement in chronic colitis-associated fibrosis it is not yet known. In this study we evaluated the immunohistochemical expression of some proteins implicated in sphingosine kinase/sphingosine 1 phosphate and transforming growth factor-β/Smads pathways in Dextrane Sodium Sulphate (DSS)- induced colorectal fibrosis in mice. Compared to control mice, DSS-induced chronic colitis mice developed a marked intestinal fibrosis associated with a concomitant overexpression of TGF-β, p-Smad3, α-SMA, collagen I-III, SPHK1, RhoA, PI3K, Akt, p-Akt, p-mTOR. This study highlights the relationship between the two pathways and the possible role of SPHK1 in the intestinal fibrosis. These results, if confirmed by in vitro studies, may have important clinical implications in the development of new therapeutical approaches in inflammatory bowel disease.

UniPR1331, a small molecule targeting Eph/ephrin interaction, prolongs survival in glioblastoma and potentiates the effect of antiangiogenic therapy in mice

Glioblastoma multiforme (GBM) is the most malignant brain tumor, showing high resistance to standard therapeutic approaches that combine surgery, radiotherapy, and chemotherapy. As opposed to healthy tissues, EphA2 has been found highly expressed in specimens of glioblastoma, and increased expression of EphA2 has been shown to correlate with poor survival rates. Accordingly, agents blocking Eph receptor activity could represent a new therapeutic approach. Herein, we demonstrate that UniPR1331, a pan Eph receptor antagonist, possesses significant in vivo anti-angiogenic and anti-vasculogenic properties which lead to a significant anti-tumor activity in xenograft and orthotopic models of GBM. UniPR1331 halved the final volume of tumors when tested in xenografts (p<0.01) and enhanced the disease-free survival of treated animals in the orthotopic models of GBM both by using U87MG cells (40 vs 24 days of control, p<0.05) or TPC8 cells (52 vs 16 days, p<0.01). Further, the association of UniPR1331 with the anti-VEGF antibody Bevacizumab significantly increased the efficacy of both monotherapies in all tested models. Overall, our data promote UniPR1331 as a novel tool for tackling GBM.

Immunolocalization of Advanced Glycation End Products, Mitogen Activated Protein Kinases, and Transforming Growth Factor-β/Smads in Pelvic Organ Prolapse

Collagen and matrix metalloproteinases (MMP) play a pivotal role in the pathophysiology of Pelvic Organ Prolapse (POP) as a switch between type I and III collagen together with a simultaneous activation of MMPs have been observed in the vaginal wall. The aim of this study was to evaluate the Advanced Glycation End (AGE) products, ERK1/2 and transforming growth factor (TGF)-β/Smad pathway expression in muscularis propria in women with POP compared with control patients. We examined 20 patients with POP and 10 control patients treated for uterine fibromatosis. Immunohistochemical analysis using AGE, RAGE, ERK1/2, Smads-2/3, Smad-7, MMP-3, and collagen I-III, TIMP, and α-SMA were performed. Smad-2/3, Smad-7, AGE, ERK1/2, p-ERK, and p-Smad3 were also evaluated using Western-blot analysis. POP samples from the anterior vaginal wall showed disorganization of the normal muscularis architecture. In POP samples, AGE, ERK1/2, Smad-2/3, MMP-3, and collagen III were upregulated in muscularis whereas in controls, Smad-7 and collagen I were increased. The receptor for AGEs (RAGE) was mild or absent both in controls and prolapse. We demonstrated the involvement of these markers in women with POP but further studies are required to elucidate if the overexpression of these molecules could play a crucial role in the pathophysiology of POP disease.

Episode-like pulse testosterone supplementation induces tumor senescence and growth arrest down-modulating androgen receptor through modulation of p-ERK1/2, pARser81 and CDK1 signaling: biological implications for men treated with testosterone replacement therapy

Despite the growing body of knowledge showing that testosterone (T) may not significantly affect tumor progression in hypogonadal patients treated for prostate cancer (Pca), the use of this hormone in this population still remains controversial. The effects of continuous or pulsed T stimulation were tested in vitro and in vivo on androgen-sensitive Pca cell lines in order to assess the differential biological properties of these two treatment modalities. Pulsed T treatment resulted in a greater inhibition than continuous T supplementation of tumor growth in vitro and in vivo. The effects of pulsed T treatment on tumor growth inhibition, G0/G1 cell cycle arrest, and tumor senescence was more pronounced than those obtained upon continuous T treatments. Mechanistic studies revealed that G0/G1 arrest and tumor senescence upon pulsed T treatment were associated with a marked decrease in cyclin D1, c-Myc and SKp2, CDK4 and p-Rb levels and upregulation of p27 and p-ERK1/2. Pulsed, but not continuous, T supplementation decreased the expression levels of AR, p-AR^ser81 and CDK1 in both cellular models. The in vitro results were confirmed in an in vivo xenografts, providing evidence of a greater inhibitory activity of pulsed supraphysiological T supplementation than continuous treatment, both in terms of tumor volume and decreased AR, p-AR^ser81, PSA and CDK1 staining. The rapid cycling from hypogonadal to physiological or supra-physiological T intraprostatic concentrations results in cytostatic and senescence effects in preclinical models of androgen-sensitive Pca. Our preclinical evidence provides relevant new insights in the biology of Pca response to pulsed T supplementation.

Pharmacological treatment with inhibitors of nuclear export enhances the antitumor activity of docetaxel in human prostate cancer

Background and aims

Docetaxel (DTX) modestly increases patient survival of metastatic castration-resistant prostate cancer (mCRPC) due to insurgence of pharmacological resistance. Deregulation of Chromosome Region Maintenance (CRM-1)/ exportin-1 (XPO-1)-mediated nuclear export may play a crucial role in this phenomenon.

Material and methods

Here, we evaluated the effects of two Selective Inhibitor of Nuclear Export (SINE) compounds, selinexor (KPT-330) and KPT-251, in association with DTX by using 22rv1, PC3 and DU145 cell lines with their. DTX resistant derivatives.

Results and conclusions

We show that DTX resistance may involve overexpression of β-III tubulin (TUBB3) and P-glycoprotein as well as increased cytoplasmic accumulation of Foxo3a. Increased levels of XPO-1 were also observed in DTX resistant cells suggesting that SINE compounds may modulate DTX effectiveness in sensitive cells as well as restore the sensitivity to DTX in resistant ones. Pretreatment with SINE compounds, indeed, sensitized to DTX through increased tumor shrinkage and apoptosis by preventing DTX-induced cell cycle arrest. Basally SINE compounds induce FOXO3a activation and nuclear accumulation increasing the expression of FOXO-responsive genes including p21, p27 and Bim causing cell cycle arrest. SINE compounds-catenin and survivin supporting apoptosis. βdown-regulated Cyclin D1, c-myc, Nuclear sequestration of p-Foxo3a was able to reduce ABCB1 and TUBB3 H2AX levels, prolonged γ expression. Selinexor treatment increased DTX-mediated double strand breaks (DSB), and reduced the levels of DNA repairing proteins including DNA PKc and Topo2A. Our results provide supportive evidence for the therapeutic use of SINE compounds in combination with DTX suggesting their clinical use in mCRPC patients.

Development of hepatocellular cancer induced by long term low fat-high carbohydrate diet in a NAFLD/NASH mouse model

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease. It can progress to nonalcoholic steatohepatitis (NASH) and, in a percentage of cases, to hepatocarcinogenesis. The strong incidence in western countries of obesity and metabolic syndrome, whose NAFLD is the hepatic expression, is thought to be correlated to consumption of diets characterized by processed food and sweet beverages. Previous studies described high-fat diet-induced liver tumors. Conversely, the involvement of low-fat/high-carbohydrate diet in the progression of liver disease or cancer initiation has not been described yet. Here we show for the first time hepatic cancer formation in low-fat/high-carbohydrate diet fed NAFLD/NASH mouse model. Animals were long term high-fat, low-fat/high-carbohydrate or standard diet fed. We observed progressive liver damage in low-fat/high-carbohydrate and high-fat animals after 12 and, more, 18 months. Tumors were detected in 20% and 50% of high-fat diet fed mice after 12 and 18 months and, interestingly, in 30% of low-fat/high-carbohydrate fed animals after 18 months. No tumors were detected in standard diet fed mice. Global increase of hepatic interleukin-1β, interleukin-6, tumor necrosis factor-α and hepatocyte growth factor was detected in low-fat/high-carbohydrate and high-fat with respect to standard diet fed mice as well as in tumor with respect to non-tumor bearing mice. A panel of 15 microRNAs was analyzed: some of them revealed differential expression in low-fat/high-carbohydrate with respect to high-fat diet fed groups and in tumors. Data here shown provide the first evidence of the involvement of low-fat/high-carbohydrate diet in hepatic damage leading to tumorigenesis.

The possible prognostic role of histone deacetylase and transforming growth factor β/Smad signaling in high grade gliomas treated by radio-chemotherapy: a preliminary immunohistochemical study

Glioblastoma (GBM) is the most common and aggressive tumor of the central nervous system. Unfortunately, patients affected by this disease have a very poor prognosis, due to high level of invasiveness and resistance to standard therapies. Although the molecular profile of GBM has been extensively investigated, the events responsible for its pathogenesis and progression remain largely unknown. Histone Deacetylases (HDAC) dependent epigenetic modifications and transforming growth factor (TGF)-β/Smad pathway seem to play an important role in GBM tumorigenesis, resistance to common therapies and poor clinical outcome. The aim of this study was to evaluate the involvement and the possible interaction between these two molecular cascades in the pathogenesis and prognosis of GBM. Immunohistochemistry (IHC) was performed on microdissected GBM samples, collected from 14 patients (6 men and 8 women) ranging in age from 43 to 74 years. The patients were previously divided, on the basis of their overall survival (OS), into two groups: short and long OS. Patients with poor prognosis showed hyperexpression of HDAC4 and HDAC6, an activation of the TGF-β/Smad pathway, with high levels of IL-13, SMAD2, PDGF and MMP3 expression, compared to the long survivors. The short OS group exhibits a decrease in SMAD7 expression and also low levels of p21 immunostaining, which represents a common target of the two pathways. The IHC data was confirmed by quantitative analysis and Immunoblotting. Our preliminary results suggest that both HDAC4 and HDAC6 together with the TGF-β/Smad pathway may be involved in progression of GBM and this cross talking could be a useful prognostic marker in this deadly disease.

Role of glycogen synthase kinase-3β and PPAR-γ on epithelial-to-mesenchymal transition in DSS-induced colorectal fibrosis

Background

Intestinal fibrosis is characterized by abnormal production and deposition of extracellular matrix (ECM) proteins by activated myofibroblasts. The main progenitor cells of activated myofibroblasts are the fibroblasts and the epithelial cells, the latter through the epithelial-mesenchymal transition (EMT).

Aim

To evaluate the action of the new PPAR-γ modulator, GED-0507-34 Levo (GED) on the expression of EMT associated and regulatory proteins such as TGF-β, Smad3, E-cadherin, Snail, ZEB1, β-catenin, and GSK-3β, in a mouse model of DSS-induced intestinal fibrosis.

Methods

Chronic colitis and fibrosis were induced by oral administration of 2.5% DSS (w/v) for 6 weeks. GW9662 (GW), a selective PPAR-γ inhibitor, was also administered by intraperitoneal injection at the dose of 1 mg/kg/day combined with GED treatment. All drugs were administered at the beginning of the second cycle of DSS (day 12). 65 mice were randomly divided into five groups (H₂O as controls n = 10, H₂O+GED n = 10, DSS n = 15, DSS+GED n = 15, DSS+GED+GW n = 15). The colon was excised for macroscopic examination and histological and morphometric analyses. The level of expression of molecules involved in EMT and fibrosis, like TGF-β, Smad3, E-cadherin, Snail, ZEB1, β-catenin, GSK-3β and PPAR-γ, was assessed by immunohistochemistry, immunofluorescence, western blot and Real Time PCR.

Results

GED improved the DSS-induced chronic colitis and fibrosis. GED was able to reduce the expression of the main fibrosis markers (α-SMA, collagen I-III and fibronectin) as well as the pivotal pro-fibrotic molecules IL-13, TGF-β and Smad3, while it increased the anti-fibrotic PPAR-γ. All these GED effects were nullified by co-administration of GW with GED. Furthermore, GED was able to normalize the expression levels of E-cadherin and β-catenin and upregulated GSK-3β, that are all known to be involved both in EMT and fibrosis.

Conclusions

The DSS-induced intestinal fibrosis was improved by the new PPAR-γ modulator GED-0507-34 Levo through the modulation of EMT mediators and pro-fibrotic molecules and through GSK-3β induction.

Changes in muscularis propria of anterior vaginal wall in women with pelvic organ prolapse

The objective of this study was to evaluate the morphological and immunohistochemical alterations of tissue removed from the upper third of anterior vaginal wall in a sample group of the female population presenting homogenous risk factors associated with pelvic organ prolapse (POP). The case study consisted of 14 patients with POP and there were 10 patients in the control group. Patient selection was carried on the basis of specific criteria and all of the patients involved in the study presented one or more of the recognized POP risk factors. Samples were taken from POP patients during vaginal plastic surgery following colpohysterectomy, and from control patients during closure of the posterior fornix following hysterectomy. Samples were processed for histological and immunohistochemical analyses for Collagen I and Collagen III, α-Smooth Muscle Actin (α-SMA), Platelet-Derived-Growth-Factor (PDGF), matrix metalloproteinase 3 (MMP3), tissue inhibitors metalloproteinase 1 (TIMP1), Caspase3. Immunofluorescence analyses for Collagen I and III and PDGF were also carried out. In prolapsed specimens our results show a disorganization of smooth muscle cells that appeared to have been displaced by an increased collagen III deposition resulting in rearrangement of the muscularis propria architecture. These findings suggest that the increase in the expression of collagen fibers in muscularis could probably be due to a phenotypic switch resulting in the dedifferentiation of smooth muscle cells into myofibroblasts. These alterations could be responsible for the compromising of the dynamic functionality of the pelvic floor.

MicroRNA expression analysis in high fat diet-induced NAFLD-NASH-HCC progression: study on C57BL/6J mice

Background

Hepatocellular carcinoma (HCC) is the most common malignant tumor of the liver. Non-alcoholic fatty liver disease (NAFLD) is a frequent chronic liver disorder in developed countries. NAFLD can progress through the more severe non alcoholic steatohepatitis (NASH), cirrhosis and, lastly, HCC. Genetic and epigenetic alterations of coding genes as well as deregulation of microRNAs (miRNAs) activity play a role in HCC development. In this study, the C57BL/6J mouse model was long term high-fat (HF) or low-fat (LF) diet fed, in order to analyze molecular mechanisms responsible for the hepatic damage progression.

Methods

Mice were HF or LF diet fed for different time points, then plasma and hepatic tissues were collected. Histological and clinical chemistry assays were performed to assess the progression of liver disease. MicroRNAs’ differential expression was evaluated on pooled RNAs from tissues, and some miRNAs showing dysregulation were further analyzed at the individual level.

Results

Cholesterol, low and high density lipoproteins, triglycerides and alanine aminotransferase increase was detected in HF mice. Gross anatomical examination revealed hepatomegaly in HF livers, and histological analysis highlighted different degrees and levels of steatosis, inflammatory infiltrate and fibrosis in HF and LF animals, demonstrating the progression from NAFLD through NASH. Macroscopic nodules, showing typical neoplastic features, were observed in 20 % of HF diet fed mice. Fifteen miRNAs differentially expressed in HF with respect to LF hepatic tissues during the progression of liver damage, and in tumors with respect to HF non tumor liver specimens were identified. Among them, miR-340-5p, miR-484, miR-574-3p, miR-720, whose expression was never described in NAFLD, NASH and HCC tissues, and miR-125a-5p and miR-182, which showed early and significant dysregulation in the sequential hepatic damage process.

Conclusions

In this study, fifteen microRNAs which were modulated in hepatic tissues and in tumors during the transition NAFLD-NASH-HCC are reported. Besides some already described, new and early dysregulated miRNAs were identified. Functional analyses are needed to validate the results here obtained, and to better define the role of these molecules in the progression of the hepatic disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-2007-1) contains supplementary material, which is available to authorized users.

Ischemia reperfusion of the hepatic artery induces the functional damage of large bile ducts by changes in the expression of angiogenic factors

Liver transplantation and cholangiocarcinoma induce biliary dysfunction following ischemia reperfusion (IR). The function of the intrahepatic biliary tree is regulated by both autocrine and paracrine factors. The aim of the study was to demonstrate that IR-induced damage of cholangiocytes is associated with altered expression of biliary angiogenic factors. Normal and bile duct ligation rats underwent 24-h sham or hepatic reperfusion after 30 min of transient occlusion of the hepatic artery (HAIR) or portal vein (PVIR) before collecting liver blocks and cholangiocyte RNA or protein. We evaluated liver histology, biliary apoptosis, proliferation and expression of VEGF-A/C, VEGFR-2/3, Ang-1/2, and Tie-1/2 in liver sections and isolated small and large cholangiocytes. Normal rat intrahepatic cholangiocyte cultures (NRICC) were maintained under standard conditions in normoxic or under a hypoxic atmosphere for 4 h and then transferred to normal conditions for selected times. Subsequently, we measured changes in biliary proliferation and apoptosis and the expression of VEGF-A/C and VEGFR-2/3. In vivo, HAIR (but not PVIR) induced damage of large bile ducts and decreased proliferation and secretin-stimulated cAMP levels. HAIR-induced damage of large bile ducts was associated with increased expression of VEGF-A/C, VEGFR-2/3, Ang-1/2, and Tie-1/2. In vitro, under hypoxic conditions, there was increased apoptosis and reduced proliferation of NRICC concomitant with enhanced expression of VEGF-A/C and VEGFR-2/3. The functional damage of large bile ducts by HAIR and hypoxia is associated with increased expression of angiogenic factors in small cholangiocytes, presumably due to a compensatory mechanism in response to biliary damage.

Contribution of intestinal smooth muscle to Crohn's disease fibrogenesis

Mesenchymal cells transdifferentiation and extracellular matrix deposition are involved in the fibrotic process of Crohn's disease (CD). Mesenchymal smooth muscle cells (SMCs) de-differentiation, driven by Platelet-derived growth factor (PDGF) that counteracts Transforming growth factor (TGF-β) has been studied in vascular muscle. The role of SMCs in intestinal fibrogenesis is still not clearly elucidated. Aim of the study was to evaluate the possible myogenic contribution to CD fibrotic process through the comparative analysis of histological, morphometric and molecular alterations occurring in human smooth muscle. Full thickness specimens were obtained from CD (non-involved and stenotic tracts) and healthy (control) ileum. Tissues were processed for histological and immunohistochemical (IHC) analyses and SMCs were isolated from the muscularis propria for morphofunctional and molecular (qPCR) analyses. CD stenotic ileum showed a significant increased thickness of all layers compared to CD non-involved and control ileum. IHC revealed an overexpression of α-smooth muscle actin and collagens I-III throughout all intestinal layers only in stenotic tracts. The two growth factors, PDGF and TGF-β, showed a progressive increase in expression in the muscle layer from CD non-involved to stenotic tracts. Freshly isolated SMCs presented alterations in CD non-involved tracts that progressively increased in the stenotic tracts consisting in a statistical increase in mRNA encoding for PDGF-β and collagen III, paralleled to a decrease in TGF-β and Tribbles-like protein-3 mRNA, and altered morphofunctional parameters consisting in progressive decreases in cell length and contraction to acetylcholine. These findings indicate that intrinsic myogenic alterations occur in CD ileum, that they likely precede stricture formation, and might represent suitable new targets for anti-fibrotic interventions.

Immunopathogenesis of psoriasis: a possible role of TGFbeta/Smads pathway

Psoriasis is a chronic immune-mediated inflammatory skin disease with both genetic and environmental factors contributing to its pathogenesis. Transforming Growth Factor beta (TGFbeta) is a member of a large family of pleiotropic cytokines with three different isoforms (TGFbeta1,2,3). Smads are a family of eight-related proteins that function as intracellular signaling intermediates for TGFbeta once the latter is bound to its receptors (TGFbRI, II and III). The involvement of Smads in TGFbeta signaling has been studied intensively in the skin in the process of wound healing. Few studies, and with controversial results, have investigated at the immunohistochemical and molecular level the role of TGFbeta/Smads signaling in psoriasis.

Features of intestinal lesions in the clinical course of inflammatory bowel diseases

Inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), are chronic, progressive and relapsing inflammatory disorders of unknown etiology. UC is characterized by inflammation of the large bowel mucosa and submucosa, whereas in CD inflammation is transmural and may involve various sites of the gastrointestinal tract. Superficial mucosal lesions are most prone to heal, whereas deep ulcers or transmural fissures may heal with more difficulty and may be followed by the development of fibrosis and strictures requiring surgery. Inflammation appears to be necessary to trigger the onset of the fibrotic process, but subsequently plays a minor role in its progression. In IBD, anti-inflammatory treatment does not prevent evolution of fibrosis once the process has started. Therefore, the mechanisms that regulate fibrosis appear to be distinct from those regulating inflammation. Intestinal fibrosis is due to an abnormal accumulation of extracellular matrix proteins producted by activated intestinal myofibroblasts. Increased evidence indicate that a number of molecules are involved in the development of the disease and a crosstalk between TGFbeta/Smads pathway and alphavbeta6 integrin, mTOR and PPARgamma could play a crucial role in the development of intestinal fibrosis. Animal models represent a useful tool to investigate the molecular and cellular mechanisms of intestinal inflammation and fibrosis and to test the effectiveness of novel therapeutic strategies for the prevention and treatment of intestinal fibrosis that still remain the major cause of surgical intervention.

Localization of ανβ6 integrin-TGF-β1/Smad3, mTOR and PPARγ in experimental colorectal fibrosis

A simultaneous action of several pro-fibrotic mediators appears relevant in the development of fibrosis. There are evidences that transforming growth factor-β (TGF-β)/Smad3 pathway forms with αvβ6 integrin, mammalian target of Rapamycin (mTOR) and peroxisome proliferator-activated receptor-γ (PPARγ) a complex signalling network with extensive crosstalk and strong effects on fibrosis development. The present study evaluated the expression of TGFβ, Smad3, αvβ6 integrin, mTOR and PPARγ in 2, 4, 6-trinitrobenzenesulphonic acid (TNBS)-induced colorectal fibrosis in Smad3 wild-type (WT) and null mice. Smad3 WT mice treated with TNBS developed a marked colorectal fibrosis and showed a concomitant up-regulation of TGFβ, Smad3, αvβ6 and mTOR and a reduction of PPARγ expression. On the other hand, Smad3 Null mice similarly treated with TNBS did not develop fibrosis and showed a very low or even absent expression of TGFβ, Smad3, αvβ6 and mTOR and a marked over-expression of PPARγ. At the same time the expression of α-smooth muscle actin (a marker of activated myofibroblasts), collagen I-III and connective tissue growth factor (a downstream effector of TGFβ/Smad3-induced extracellular matrix proteins) were up-regulated in Smad3 WT mice treated with TNBS compared to Null TNBS-treated mice. These preliminary results suggest a possible interaction between these pro-fibrotic molecules in the development of intestinal fibrosis.

Can we prevent, reduce or reverse intestinal fibrosis in IBD?

Intestinal fibrosis is a common complication of in inflammatory bowel disease (IBD) and can occur in both ulcerative colitis (UC) and Crohn's disease (CD), but is much more prevalent in CD. Fibrosis is a consequence of local chronic inflammation and is characterized by abnormal deposition of extracellular matrix (ECM) proteins producted by activated myofibroblasts. Current anti-inflammatory therapies used in IBD do not prevent nor they reverse established fibrosis and strictures. Despite the therapeutic advance in the treatment of IBD in the last two decades, the incidence of intestinal strictures in CD has not significantly changed. This implies that control of intestinal inflammation does not necessarily affect the associated fibrotic process. The conventional view that intestinal fibrosis is an inevitable and irreversible process in patients with IBD is progressively changing in light of improved understanding of the cellular and molecular mechanisms that underline the pathogenesis of fibrosis. Comprehension of the mechanisms of intestinal fibrosis may pave the way for the developments of anti-fibrotic agents and of new possible therapeutic approches in IBD. Nevertheless, there are important clinical issues that need further investigations, in particular the identification of factors relevant for the development of the intestinal fibrosis in IBD and the need of accurate and effective monitoring of the fibrotic progression and of effectiveness of the new proposed treatments.

Boswellia serrata and Salvia miltiorrhiza extracts reduce DMN-induced hepatic fibrosis in mice by TGF-beta1 downregulation

BACKGROUND

Hepatic fibrosis is characterised by a progressive accumulation of fibrillar extracellular matrix (ECM) proteins, including collagen that occurs in chronic liver diseases. Transforming growth factor-beta1 (TGF-beta)/Smad3 signalling plays a major role in tissue fibrogenesis acting as a potent stimulus of ECM accumulation.

AIM

To evaluate the effects of a combined therapy with anti-inflammatory Boswellia and anti-fibrotic Salvia extracts on the course of chronic hepatitis-associated fibrosis induced by dimethylnitrosamine (DMN) in mice, as well as on the hepatic expression of TGF-beta1 and Smad proteins.

METHODS

Chronic hepatitis-associated fibrosis was induced in mice by intraperitoneal DMN administration. Mice were assigned to 5 groups: controls; DMN without any treatment; DMN treated orally with Boswellia extracts (50 mg/kg/day); DMN treated orally with Salvia extracts (150 mg/ kg/day); DMN treated orally with both Boswellia (50 mg/kg/day) and Salvia extracts (150 mg/kg/ day). The liver was excised for macroscopic examination and histological, morphometric and immunohistochemical (IHC) analyses. For IHC, alpha-smooth muscle actin (alpha-SMA), collagen types I-III, TGF-beta1, connective tissue growth factor (CTGF), Smad3, Smad7, CD3, PCNA and TUNEL antibodies were used.

RESULTS

The combined oral administration of Boswellia and Salvia extracts improved the course and macroscopic findings of DMN-induced chronic hepatitis-associated fibrosis. The histological severity of the hepatic fibrosis showed a marked improvement following treatment and was associated with a reduction in the hepatic expression of alpha-SMA, collagen I-III, CTGF, TGF-beta1, Smad3, and Smad7.

CONCLUSIONS

These data demonstrate that co-treatment of Boswellia plus Salvia extracts is effective in preventing hepatic fibrosis in DMN-induced chronic hepatitis. The anti-fibrotic properties are mainly related to Salvia extracts and appear to be mediated by the inhibition of the TGF-beta1/Smad3 pathway.

Taurocholic acid prevents biliary damage induced by hepatic artery ligation in cholestatic rats

BACKGROUND

Ischemic injury by hepatic artery ligation (HAL) during obstructive cholestasis induced by bile duct ligation (BDL) results in bile duct damage, which can be prevented by administration of VEGF-A. The potential regulation of VEGF and VEGF receptor expression and secretion by bile acids in BDL with HAL is unknown.

AIMS

We evaluated whether taurocholic acid (TC) can prevent HAL-induced cholangiocyte damage via the alteration of VEGFR-2 and/or VEGF-A expression.

METHODS

Utilizing BDL, BDL+TC, BDL+HAL, BDL+HAL+TC, and BDL+HAL+wortmannin+TC treated rats, we evaluated cholangiocyte apoptosis, proliferation, and secretion as well VEGF-A and VEGFR-2 expression by immunohistochemistry. In vitro, we evaluated the effects of TC on cholangiocyte secretion of VEGF-A and the dependence of TC-induced proliferation on the activity of VEGFR-2.

RESULTS

In BDL rats with HAL, chronic feeding of TC prevented HAL-induced loss of bile ducts and HAL-induced decreased cholangiocyte secretion. TC also prevented HAL-inhibited VEGF-A and VEGFR-2 expression in liver sections and HAL-induced circulating VEGF-A levels, which were blocked by wortmannin administration. In vitro, TC stimulated increased VEGF-A secretion by cholangiocytes, which was blocked by wortmannin and stimulated cholangiocyte proliferation that was blocked by VEGFR-2 kinase inhibitor.

CONCLUSION

TC prevented HAL-induced biliary damage by upregulation of VEGF-A expression.

H3 histamine receptor-mediated activation of protein kinase Calpha inhibits the growth of cholangiocarcinoma in vitro and in vivo

Histamine regulates functions via four receptors (HRH1, HRH2, HRH3, and HRH4). The d-myo-inositol 1,4,5-trisphosphate (IP(3))/Ca(2+)/protein kinase C (PKC)/mitogen-activated protein kinase pathway regulates cholangiocarcinoma growth. We evaluated the role of HRH3 in the regulation of cholangiocarcinoma growth. Expression of HRH3 in intrahepatic and extrahepatic cell lines, normal cholangiocytes, and human tissue arrays was measured. In Mz-ChA-1 cells stimulated with (R)-(alpha)-(-)-methylhistamine dihydrobromide (RAMH), we measured (a) cell growth, (b) IP(3) and cyclic AMP levels, and (c) phosphorylation of PKC and mitogen-activated protein kinase isoforms. Localization of PKCalpha was visualized by immunofluorescence in cell smears and immunoblotting for PKCalpha in cytosol and membrane fractions. Following knockdown of PKCalpha, Mz-ChA-1 cells were stimulated with RAMH before evaluating cell growth and extracellular signal-regulated kinase (ERK)-1/2 phosphorylation. In vivo experiments were done in BALB/c nude mice. Mice were treated with saline or RAMH for 44 days and tumor volume was measured. Tumors were excised and evaluated for proliferation, apoptosis, and expression of PKCalpha, vascular endothelial growth factor (VEGF)-A, VEGF-C, VEGF receptor 2, and VEGF receptor 3. HRH3 expression was found in all cells. RAMH inhibited the growth of cholangiocarcinoma cells. RAMH increased IP(3) levels and PKCalpha phosphorylation and decreased ERK1/2 phosphorylation. RAMH induced a shift in the localization of PKCalpha expression from the cytosolic domain into the membrane region of Mz-ChA-1 cells. Silencing of PKCalpha prevented RAMH inhibition of Mz-ChA-1 cell growth and ablated RAMH effects on ERK1/2 phosphorylation. In vivo, RAMH decreased tumor growth and expression of VEGF and its receptors; PKCalpha expression was increased. RAMH inhibits cholangiocarcinoma growth by PKCalpha-dependent ERK1/2 dephosphorylation. Modulation of PKCalpha by histamine receptors may be important in regulating cholangiocarcinoma growth.

Targeted disruption of Smad3 confers resistance to the development of dimethylnitrosamine-induced hepatic fibrosis in mice

BACKGROUND

Hepatic fibrosis is characterized by a progressive accumulation of fibrillar extracellular matrix (ECM) proteins including collagen, which occurs in most types of chronic liver diseases. Transforming growth factor-beta (TGF-beta)/Smad3 signalling plays a central role in tissue fibrogenesis, acting as a potent stimulus of ECM accumulation.

AIM

To evaluate the potential protective role of Smad3 deficiency in the pathogenesis of liver fibrosis induced by dimethylnitrosamine (DMN) in Smad3 null mice.

METHODS

Chronic hepatitis-associated fibrosis was induced in 13 Smad3 null and 13 wild-type (WT) mice by intraperitoneal DMN administration (10 microg/g body weight/day) for three consecutive days per week for 6 weeks. The liver was excised for macroscopic examination and histological, morphometric and immunohistochemical (IHC) analyses. For IHC, alpha-smooth muscle actin (alpha-SMA), collagen types I-III, TGF-beta1, connective tissue growth factor (CTGF), Smad3, Smad7 and CD3 antibodies were used.

RESULTS

At macroscopic examination, the liver of DMN-treated Smad3 WT appeared harder with a dark brown colouring and necrotic areas compared with that from null mice. Histological and morphometric evaluation revealed a significantly higher degree of hepatic fibrosis and accumulation of connective tissue in the Smad3 WT compared with null mice. IHC evaluation showed a marked increase in alpha-SMA, CTGF, collagen I-III, TGF-beta and Smad3 staining in the liver of Smad3 WT compared with that in null mice, whereas Smad7 was increased only in null mice.

CONCLUSIONS

The results indicate that Smad3 loss confers resistance to the development of DMN-induced hepatic fibrosis. The reduced fibrotic response appears to be due to a reduction of fibrogenic myofibroblast activation and ECM production and accumulation. Smad3 could be a novel target for potential treatment of fibrosis complicating chronic hepatitis.

Smad3 loss confers resistance to the development of trinitrobenzene sulfonic acid-induced colorectal fibrosis

BACKGROUND

Transforming growth factor-beta (TGF-beta)/Smad3 signalling plays a central role in tissue fibrogenesis, acting as a potent stimulus of extracellular matrix (ECM) protein accumulation. The aim of this study was to evaluate the potential role of Smad3 in the pathogenesis of colonic fibrosis induced by trinitrobenzene sulfonic acid (TNBS) in Smad3 null mice.

MATERIALS AND METHODS

Chronic colitis-associated fibrosis was induced in 15 Smad3 null and 13 wild-type mice by intra-rectal administration of TNBS. Each mouse received an incremental dose of TNBS (0.5-1.0 mg per week) over a 6-week period. The colon was excised for macroscopic examination and histological, morphometric and immunohistochemical analyses. For immunohistochemistry, alpha-smooth muscle actin (alpha-SMA), collagen types I-III, TGF-beta1, connective tissue growth factor (CTGF), Smad3, Smad7, and CD3 antibodies were used.

RESULTS

At macroscopic examination, the colon of Smad3 wild-type mice appeared significantly harder, thicker and shorter than that of the Smad3 null mice. Of the wild-type mice, 50% presented colonic adhesions and strictures. Histological and morphometric evaluation revealed a significantly higher degree of colonic fibrosis and accumulation of collagen in the Smad3 wild-type compared to null mice, whereas the degree of colonic inflammation did not differ between the two groups of mice. Immunohistochemical evaluation showed a marked increase in CTGF, collagen I-III, TGF-beta and Smad3 staining in the colon of Smad3 wild-type compared to null mice, whereas Smad7 was increased only in null mice.

CONCLUSIONS

These results indicate that Smad3 loss confers resistance to the development of TNBS-induced colonic fibrosis. The reduced fibrotic response appears to be due to a reduction in fibrogenic mesenchymal cell activation and ECM production and accumulation. Smad3 could be a novel target for potential treatment of intestinal fibrosis, especially in inflammatory bowel disease.

Prevention of colonic fibrosis by Boswellia and Scutellaria extracts in rats with colitis induced by 2,4,5-trinitrobenzene sulphonic acid

BACKGROUND

Currently, no effective preventive measures or medical therapies are available for intestinal fibrosis and, thus, surgery remains the only available strategy in the management of fibrostenotic enteropathies, especially Crohn's disease. The aim of this study was to evaluate the efficacy of a combined therapy of anti-inflammatory Boswellia and antifibrotic Scutellaria extracts on the development of colonic fibrosis in rats.

MATERIALS AND METHODS

Chronic colonic inflammation-associated fibrosis was induced in rats by intracolonic administration of 2,4,5-trinitrobenzene sulphonic acid (TNBS). Sixty-four healthy male Sprague-Dawley rats were assigned to five groups: 8 controls, 14 TNBS, 14 TNBS orally treated with Boswellia extracts (50 mg kg(-1) day(-1)), 14 TNBS orally treated with Scutellaria extracts (150 mg kg(-1) day(-1)), and 14 TNBS orally treated with both Boswellia (50 mg kg(-1) day(-1)) and Scutellaria extracts (150 mg kg(-1) day(-1)). The colon was removed after 21 days of treatment and assessed by macroscopic, histological, morphometric and immunohistochemical analyses. For immunohistochemical analysis, alpha-smooth muscle actin (alpha-SMA), collagen types I-III, connective tissue growth factor (CTGF), transforming growth factor-beta1 (TGF-beta1), Smad3, Smad7 and CD3 antibodies were used.

RESULTS

Combined oral administration of Boswellia and Scutellaria significantly improved the course and macroscopic findings of TNBS-induced chronic colitis assessed by disease activity index, colon weight, length, adhesions, strictures, dilatation, thickness, oedema, ulcerations and extension of damage. The histological severity of the colonic fibrosis was also notably improved by the treatment and associated with a significant reduction in the colonic expression of alpha-SMA, collagen I-III, CTGF, TGF-beta1, Smad3, and Smad7.

CONCLUSIONS

These data demonstrate that the prophylactic administration of anti-inflammatory Boswellia and antifibrotic Scutellaria extracts is effective in preventing colonic fibrosis in TNBS-induced colitis. Their antifibrotic mechanism of action seems to be mediated by the inhibition of TGF-beta1/Smad3 pathway.

TrkAIII expression in the thymus

The alternative TrkAIII splice variant is expressed by murine and human thymus. Alternative TrkAIII splicing predominates in postembryonic day E13 (E17 and E18), postnatal murine (3 week and 3 month) and human thymuses, with TrkAIII mRNA expressed by selected thymocyte subsets and thymic epithelial cells (TECs) and a 100 kDa immunoprecipitable TrkAIII-like protein detected in purified thymocyte and whole thymus extracts. FACS and immunohistochemical analysis indicate a non-cell surface localisation for the TrkAIII-like protein in cortical CD4+/CD8+ double positive and, to a lesser extent, single positive thymocyte subsets at the cortex/medulla boundary and in Hassle's corpuscles, reticular epithelial and dendritic cells of the thymic medulla. TrkA(I/II) expression, on the other hand, predominates in sub-capsular regions of the thymus. TrkAIII-like immunoreactivity at the cortex/medulla boundary associates with regions of thymocyte proliferation and not apoptosis. A potential role for thymic hypoxia in thymocyte alternative TrkAIII splicing is supported by reversal to TrkAI splicing by normoxic but not hypoxic culture and induction of Jurkat T cell alternative TrkAIII splicing by the hypoxia mimic CoCl2. In contrast, TEC expression of TrkAIII predominates in both normoxic and hypoxic culture conditions. The data support a potential role for TrkAIII in thymic development and function, of particular relevance to intermediate stage CD4+/CD8+ thymocyte subsets and TECs, which potentially reflects a reversible thymocyte and more permanent TEC adaptation to thymic environment. Since intracellular TrkAIII neither binds nor responds to NGF and can impede regular NGF/TrkA signalling (Tacconelli et al., Cancer Cell, 2004), its expression would be expected to provide an alternative and/or impediment to regular NGF/TrkA signalling within the developing and developed thymus of potential functional importance.

Smad3 knock-out mice as a useful model to study intestinal fibrogenesis

AIM: To evaluate the possible differences in morphology and immunohistochemical expression of CD3, transforming growth factor β1(TGF-β1), Smad7, α-smooth muscle actin (α-Sma), and collagen types I-VII of small and large intestine in Smad3 null and wild-type mice.

METHODS: Ten null and ten wild-type adult mice were sacrificed at 4 mo of age and the organs (esophagus, small and large bowel, ureters) were collected for histology(hematoxylin and eosin, Masson thrichrome, silver staining), morphometry and immunohistochemistry analysis. TGF-β1 levels of intestinal tissue homogenates were assessed by ELISA.

RESULTS: No macroscopic intestinal lesions were detected both in null and wild-type mice. Histological and morphometric evaluation revealed a significant reduction in muscle layer thickness of small and large intestine in null mice as compared to wild-type mice. Immunohistochemistry evaluation showed a significant increase of CD3+T cell, TGF-β1 and Smad7 staining in the small and large intestine mucosa of Smad3 null mice as compared to wild-type mice. α-Sma and collagen I-VII staining of small and large intestine did not differ between the two groups of mice. TGF-β1 levels of colonic tissue homogenates were significantly higher in null mice than in wild-type mice. In preliminary experiments a significant reduction of TNBS-induced intestinal fibrosis was observed in null mice as compared to wild-type mice.

CONCLUSION: Smad3 null mice are a useful model to investigate the in vivo role of the TGF-β/Smad signalling pathway in intestinal inflammation and fibrosis.

Smad3-null mice lack interstitial cells of Cajal in the colonic wall

BACKGROUND

Transforming growth factor-beta (TGF-beta)/Smad's signalling pathway plays a pivotal role in organogenesis, oncogenesis, inflammation, repair and fibrosis. The aim of this study was to evaluate the morphology of muscle layers and the density and distribution of interstitial cells of Cajal (ICC) in the colon of Smad3 knockout mice.

MATERIALS AND METHODS

Eighteen Smad3 wild-type mice and 12 null mice were sacrificed at age 4 months and the colons were collected for histology (Haematoxilin-Eosin, Masson thrichrome and Gomori silver staining), morphometry and immunohistochemistry (IHC) analysis. For IHC we used the c-Kit, alpha-smooth muscle actine (alpha-SMA), vimentin, desmin and neuronal cocktail (S-100, NSE, neurofilament 200) antibodies.

RESULTS

When sacrificed, 40% of the null mice showed different degrees of colon dilatation when compared with the wild-type. Histological and morphometric evaluation revealed a significant reduction in muscle layer thickness of the colon in all the null mice when compared with the wild-type. Immunohistochemistry evaluation showed a marked reduction, or even absence, of c-Kit immunoreactivity, which identifies ICC, in the colon of all the null mice, compared with the wild-type.

CONCLUSIONS

Smad3 null mice showed a marked reduction, or even absence, of ICC in the colon together with a concomitant reduction of intestinal smooth muscle layer thickness. This data could account for the colonic dilation observed in approximately 40% of the Smad3 null mice. Alteration of intestinal smooth muscle layers and ICC could also be involved in the resistance of the Smad3 null mice to develop colonic fibrosis.

TrkA alternative splicing: a regulated tumor-promoting switch in human neuroblastoma

We identify a novel alternative TrkA splice variant, TrkAIII, with deletion of exons 6, 7, and 9 and functional extracellular IG-C1 and N-glycosylation domains, that exhibits expression restricted to undifferentiated early neural progenitors, human neuroblastomas (NBs), and a subset of other neural crest-derived tumors. This NGF-unresponsive isoform is oncogenic in NIH3T3 cells and promotes tumorigenic NB cell behavior in vitro and in vivo (cell survival, xenograft growth, angiogenesis) resulting from spontaneous tyrosine kinase activity and IP3K/Akt/NF-kappaB but not Ras/MAPK signaling. TrkAIII antagonizes NGF/TrkAI signaling, which is responsible for NB growth arrest and differentiation through Ras/MAPK, and its expression is promoted by hypoxia at the expense of NGF-responsive receptors, providing a mechanism for converting NGF/TrkA/Ras/MAPK antioncogenic signals to TrkAIII/IP3K/Akt/NF-kappaB tumor-promoting signals during tumor progression.

Slime production by clinical isolates of Blastoschizomyces capitatus from patients with hematological malignancies and catheter-related fungemia

In order to expand the present knowledge of the pathogenic potential of Blastoschizomyces capitatus in central venous catheter (CVC)-related bloodstream infections, six strains of the organism recovered from three leukemic patients with CVC-related fungemia in different years were investigated. Isolates and control strains were tested for their genetic relatedness and for their ability to produce slime in glucose-containing solutions. DNA restriction enzyme analysis revealed that all strains of B. capitatus were identical, whereas slime production assays and examination of ex vivo material showed that they were able to produce large amounts of slime. Slime production may therefore play a relevant pathogenic role in cases of CVC-related fungemia caused by B. capitatus.

[MDR (multidrug resistance) in hepatocarcinoma clinical-therapeutic implications]

Our purpose was to summarize current knowledge on "multidrug resistance", or MDR, an intrinsic or acquired cross resistance to a variety of structurally and functionally unrelated drugs, still representing one of the major problems in the therapy of cancer and other diseases. MDR depends on various mechanisms, the best known being the activity of ABC transport proteins, mainly Pgp, MDR1 gene product,and MRPs; but also other transporters can cause resistance, for example TAP, a peptide transporter, CFTR, cystic fibrosis transmembrane regulator, ABCG2, or breast cancer resistance protein (BCRP) and LRP, lung resistance protein. MDR has been detected in nearly all types of cancer, because it affects many organs and can occur against a wide number of drugs; it is frequent even in other diseases, such as epilepsy and HIV. We focused on MDR phenomenon in HCC, one of the commonest tumors in the world, and one of the most resistant to pharmacological treatment. This characteristic might be partly determined by a link between MDR and angiogenic phenotypes. The relationship between MDR in hepatocellular carcinoma and the effectiveness of therapeutic treatments has been particularly examined. Finally, the importance to overcome the strong chemoresistance of hepatocellular carcinoma with methods alternative to drugs, namely gene therapy, which makes use of antisense oligonucleotides and anti-MDR1 ribozymes, has been pointed out.

Increased proliferation and apoptosis of colonic epithelial cells in dextran sulfate sodium-induced colitis in rats

We have evaluated morphologic alterations and epithelial cell apoptosis and proliferation of colonic mucosa in the acute and chronic phases of DSS-induced colitis. Colitis was induced in Sprague-Dawley rats by 7 days of 4% DSS oral administration followed by 7 days of tap water for one, two, and three cycles. Control rats receved tap water only. Morphological changes in colonic mucosa were evaluated and scored by light and scanning electron microscopy. Apoptosis was studied by TUNEL assay and cell proliferation by Ki-67 immunoreaction. The expression of both proapoptotic (Fas, FasL, Bax, p53) and antiapoptotic (Bc12) cellular proteins was determined by immunohistochemistry. Morphologic assessment showed the most severe colonic epithelial lesions and inflammation in the distal colon with a trend to increasing severity from the first to the third DSS cycle. In DSS rats, the epithelial apoptotic index increased 20-fold after the first cycle and 120-fold after the second and third cycles compared with the controls; in the same way, the expression index of proapoptotic proteins (Fas, FasL, Bax, p53) dramatically increased. The proliferative index increased about 40 to 60-fold compared to controls, with no difference among the three DSS cycles. In conclusion, DSS-induced colitis in rats, which has many structural and ultrastructural features similar to those seen in human ulcerative colitis, is a suitable model for studying increased epithelial apoptosis and proliferation. Further studies employing this model will permitt two hypotheses to be tested. (1) Increased apoptosis may lead to a breakdown of the epithelial barrier function and facilitate the mucosal invasion of intraluminal microorganisms and/or antigens. (2) Abnormal and persistent epithelial hyperproliferation could be causally related to the development of colorectal cancers in the setting of chronic colonic inflammation.

Catheter-related candidemia caused by Candida lipolytica in a patient receiving allogeneic bone marrow transplantation

Candida lipolytica was recovered from the blood and the central venous catheter in a patient receiving allogeneic bone marrow transplantation. Two C. lipolytica strains from different geographical areas and the ATCC 9773 strain of C. lipolytica were used as controls. C. lipolytica was identified by standard methods. MICs indicated antifungal susceptibilities to amphotericin B, fluconazole, and itraconazole for all strains. In vitro testing and scanning electron microscopy showed that C. lipolytica was capable of producing large amounts of viscid slime material in glucose-containing solution, likely responsible for the ability of the yeast to adhere to catheter surfaces. Restriction fragment length polymorphisms revealed an identical profile for all clinical isolates, unrelated to those observed for the control strains. This finding suggested the absence of microevolutionary changes in the population of the infecting strain, despite the length of the sepsis and the potential selective pressure of amphotericin B, which had been administered to the patient for about 20 days. The genomic differences that emerged between the isolates and the control strains were indicative of a certain degree of genetic diversity between C. lipolytica isolates from different geographical areas.

Peyer's patches epithelium in the rat: a morphological, immunohistochemical, and morphometrical study

The epithelial layer covering lymphoid follicles of Peyer's patches consists of cells with a different surface morphology. Some of these cells have been described as a distinct cytotype, the so-called M cells. In order to resolve the controversy on the specific morphological and biochemical markers of M cells, structural, ultrastructural, and morphometrical study of the epithelium covering the rat Peyer's patches were performed. Peyer's patches from healthy rats were processed for light microscopy, immunohistochemistry, in situ nick-end labeling (TUNEL), and scanning and transmission electron microscopy. A morphometric study was also performed to evaluate microvillus density, length, and number of lysosomes in different areas of the epithelium. Peyer's patches were covered by simple columnar/cubical dome epithelium (DE). Scarce goblet cells and a large number of enterocytes were observed. Ultrastructural observations revealed that the DE showed cells with different morphology. The density and length of microvilli and the lysosome number varied along the whole dome without significant differences. The DE cells characterized by short and disorganized microvilli appeared always in close spatial relationship with lymphocytes. In conclusion, the concept that distinct cell types (enterocytes and M cells) can be identified in the rat DE does not appear to be valid based on morphological criteria. It seems correct to consider that in rat Peyer's patches the presence of scarce goblet cells and a large number of enterocytes showing dynamic morphofunctional modifications is related to the functional state and/or to cell cycle.

Hepatic microvascular features in experimental cirrhosis: a structural and morphometrical study in CCl4-treated rats

BACKGROUND/AIMS

In this study, a detailed morphometrical analysis of the hepatic microvasculature in the different zones of hepatic parenchyma was performed in normal and cirrhotic rat liver (CCl4-induced). The aims were to detect, in CCl4-induced cirrhosis, the real presence of the "capillarization" of hepatic sinusoids and to assess alterations of the sinusoid/parenchyma ratio within the nodule.

METHODS

Cirrhosis was promoted by controlled intragastric CCl4 administration. Scanning electron microscopy of the vascular corrosion cast technique associated with light microscopy and transmission electron microscopy were used.

RESULTS

Evidence of connective tissue in the space of Disse was found only in sinusoids located near portal tracts or large fibrotic areas, and this was also confirmed by laminin immunohistochemistry. In contrast, all the intranodular sinusoids lacked real basal membrane and connective fibers in the space of Disse and, displayed normal fenestrations. The parenchymal area, sinusoidal area, mean sinusoidal area, sinusoidal perimeter, hepatocyte area and the reciprocal ratios were all considered in the morphometrical analysis. The sinusoids were of uniform size in the periportal, periseptal and pericentral areas of the cirrhotic liver without the typical zonal differences of the normal liver. The areas occupied by sinusoids per unit of parenchyma and the sinusoid/hepatocyte interfaces disposable for metabolic exchanges were markedly smaller (p<0.01) in cirrhotic than normal liver.

CONCLUSION

Our findings indicate that capillarization of hepatic sinusoids occurs only in very limited regions of the cirrhotic parenchyma, and thus this phenomenon does not have relevant functional consequences. Furthermore, the cirrhotic parenchyma appears not to be supplied by sinusoids and lacks features of zonation, which is a condition that could play a major role in the development and progression of liver failure.

Onychomycosis caused by Blastoschizomyces capitatus

Blastoschizomyces capitatus was cultured from the nail of a healthy patient with onychomycosis. The identity of the isolate was initially established by standard methods and ultrastructural analysis and was verified by molecular probing. Strains ATCC 200929, ATCC 62963, and ATCC 62964 served as reference strains for these analyses. To our knowledge, this is the first case of nail infection secondary to paronychia caused by this organism reported in the English literature.

Dextran sulfate sodium (DSS) colitis in rats: clinical, structural, and ultrastructural aspects

Aim of this study was to assess the structural, ultrastructural, immunohistochemical, and clinical aspects in Sprague-Dawley rats with dextrane sulfate sodium (DSS)-induced colitis. Colitis was induced in Sprague-Dawley rats by seven days of DSS oral administration followed by seven days of tap water only (for one, two and three cycles). Controls were fed with water only. Segments of proximal, mid-, and distal colon of each animal were adequately prepared for light and scanning electron microscope observations. The severity of the lesions was scored histologically. For immunohistochemical study, a cocktail of S-100, NSE, and antineurofilament antibodies was used. Symptoms such as weight, feces consistency, diarrhea, hematochezia were recorded daily. From a clinical point of view symptoms appeared significantly later after the first cycle than after the second and third cycles and lasted significantly longer in the second and third cycles. Treated rats showed a slower weight gain rate by 20% compared to controls, and the whole colon length appeared to be significantly shorter after colitis induction compared to controls. Structural observations by light microscopy showed prominent involvement of the distal colon. Immunohistochemical study of both submucosal and myoenteric nerve plexuses was similar to controls. Scanning electron microscope observations of the colonic mucosal surface in colitis rats showed a complete subversion of its architecture, characterized by dilatations of gland crypt openings, dropout of goblet cells, and inhomogeneous distribution or lack of microvilli. These were most evident after the third cycle. In conclusion, experimental DSS colitis in SD rats appeared to be highly reproducible and shared most features with human UC, not only from a structural and clinical but also from an ultrastructural point of view.

Liver metabolic zonation and hepatic microcirculation in carbon tetrachloride-induced experimental cirrhosis

The exact cause of the hepatic failure in liver cirrhosis is currently unclear, and two main theories have been proposed: the first is based on the altered hepatocyte function (sick hepatocyte hypothesis); the second on the abnormal hepatic architecture (intact hepatocyte hypothesis). Moreover, the microcirculation, a fundamental component in liver structure, shows dramatic changes in cirrhosis that would heavily influence the development of the disease. In order to determine the importance of the microvascular alterations on liver morphofunctional features in experimentally induced cirrhosis, their relationships with structural, ultrastructural, and histoenzymological hepatocyte modifications were investigated. Experimental cirrhosis was induced with controlled intragastric CCl4 administration. Scanning electron microscopy of the vascular corrosion cast technique, associated with light microscopy, transmission electron microscopy, and histoenzymology techniques were employed. The results demonstrated a characteristic micronodular cirrhosis in all the livers studied; the microcirculation displayed the presence of newly formed perinodular plexus. Inside the nodule, areas with two or more hepatocyte-thick laminae were present. Moreover, a rearrangement of the hepatocyte quantitative ultrastructure without real pathological changes and a loss of normal metabolic lobular zonation were noted in the liver parenchyma. These findings support the concept that the progressive modifications of the microcirculation during experimental CC14 cirrhosis modify not only the normal blood flow direction, but also the normal hepatic metabolic gradient with a loss of the normal hepatocytic zonation.