Changes in HLA-B27 Transgenic Rat Fecal Microbiota Following Tofacitinib Treatment and Ileocecal Resection Surgery: Implications for Crohn's Disease Management.

The therapeutic management of Crohn's disease (CD), a chronic relapsing-remitting inflammatory bowel disease (IBD), is highly challenging. Surgical resection is sometimes a necessary procedure even though it is often associated with postoperative recurrences (PORs). Tofacitinib, an orally active small molecule Janus kinase inhibitor, is an anti-inflammatory drug meant to limit PORs in CD. Whereas bidirectional interactions between the gut microbiota and the relevant IBD drug are crucial, little is known about the impact of tofacitinib on the gut microbiota. The HLA-B27 transgenic rat is a good preclinical model used in IBD research, including for PORs after ileocecal resection (ICR). In the present study, we used shotgun metagenomics to first delineate the baseline composition and determinants of the fecal microbiome of HLA-B27 rats and then to evaluate the distinct impact of either tofacitinib treatment, ileocecal resection or the cumulative effect of both interventions on the gut microbiota in these HLA-B27 rats. The results confirmed that the microbiome of the HLA-B27 rats was fairly different from their wild-type littermates. We demonstrated here that oral treatment with tofacitinib does not affect the gut microbial composition of HLA-B27 rats. Of note, we showed that ICR induced an intense loss of bacterial diversity together with dramatic changes in taxa relative abundances. However, the oral treatment with tofacitinib neither modified the alpha-diversity nor exacerbated significant modifications in bacterial taxa induced by ICR. Collectively, these preclinical data are rather favorable for the use of tofacitinib in combination with ICR to address Crohn's disease management when considering microbiota.

Passages in culture and stimulation conditions influence protein expression of primary fibroblasts.

Fibroblasts (Fb) are key effector cells in systemic sclerosis (SSc). Fb stimulation with transforming growth factor beta 1 (TGF-ß1) is considered as a positive control in studies assessing fibrogenesis. The lack of standardization of TGF-ß1 stimulation might be responsible for discrepancies in experiments performed in different conditions. Using quantitative proteomics analysis, we evaluated the impact of changes in experimental conditions on proteomic profiles of primary Fb. Principal component analysis (PCA) identified several groups of differentially expressed proteins influenced by cell passage, culture medium, and both concentration and duration of exposure to TGF-ß1 stimulation. Bioinformatics analysis revealed that late passages expressed proteins involved in senescence. TGF-ß1 concentration and time of stimulation were correlated with the expression of proteins involved in the fibrogenesis and inflammatory processes. These data underline the need for standardization of culture conditions to allow inter-data comparisons in future in vitro studies, especially when using "omics" approaches.

TLR9-mediated dendritic cell activation uncovers mammalian ganglioside species with specific ceramide backbones that activate invariant natural killer T cells.

CD1d-restricted invariant natural killer T (iNKT) cells represent a heterogeneous population of lipid-reactive T cells that are involved in many immune responses, mediated through T-cell receptor (TCR)-dependent and/or independent activation. Although numerous microbial lipid antigens (Ags) have been identified, several lines of evidence have suggested the existence of relevant Ags of endogenous origin. However, the identification of their precise nature as well as the molecular mechanisms involved in their generation are still highly controversial and ill defined. Here, we identified two mammalian gangliosides-namely monosialoganglioside GM3 and disialoganglioside GD3-as endogenous activators for mouse iNKT cells. These glycosphingolipids are found in Toll-like receptor-stimulated dendritic cells (DC) as several species varying in their N-acyl fatty chain composition. Interestingly, their ability to activate iNKT cells is highly dependent on the ceramide backbone structure. Thus, both synthetic GM3 and GD3 comprising a d18:1-C24:1 ceramide backbone were able to activate iNKT cells in a CD1d-dependent manner. GM3 and GD3 are not directly recognized by the iNKT TCR and required the Ag presenting cell intracellular machinery to reveal their antigenicity. We propose a new concept in which iNKT cells can rapidly respond to pre-existing self-molecules after stress-induced structural changes in CD1d-expressing cells. Moreover, these gangliosides conferred partial protection in the context of bacterial infection. Thus, this report identified new biologically relevant lipid self-Ags for iNKT cells.

Treatments for Crohn's Disease-Associated Bowel Damage: A Systematic Review.

BACKGROUND & AIMS: Despite significant advances in the treatment of Crohn's disease (CD), most patients still develop stricturing or penetrating complications that require surgical resections. We performed a systematic review of mechanisms and potential treatments for tissue damage lesions in CD patients. METHODS: We searched the PubMed, MBASE, and Cochrane databases from January 1960 to July 2017 for full-length articles on CD, fibrosis, damage lesions, mesenchymal stem cells, and/or treatment. We also searched published conference abstracts and performed manual searches of all reference lists of relevant articles. RESULTS: Mechanisms of intestinal damage in patients with CD include fibroblast proliferation and migration, activation of stellate cells, recruitment of intestinal or extra-intestinal fibroblast, and cell trans-differentiation. An altered balance of metalloproteinases and tissue inhibitors of metalloproteinases might contribute to fistula formation. Treatment approaches that reduce excessive transforming growth factor beta (TGFB) activation might be effective in treating established intestinal damage. Stem cell therapies have been effective in tissue damage lesions in CD. Particularly, randomized controlled trials have shown local injections of mesenchymal stem cells to heal perianal fistulas. CONCLUSION: In a systematic review of mechanisms and treatments of bowel wall damage in patients with CD, we found a need to test drugs that reduce TGFB and increase healing of transmural damage lesions and to pursue research on local injection of mesenchymal stem cells.

Peroxisome proliferator-activated receptor gamma in the colon: inflammation and innate antimicrobial immunity.

Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor, originally described in adipose tissue, which controls the expression of a large number of regulatory genes in lipid metabolism and insulin sensitization. Well known by endocrinologists, thiazolidinedionesare classical PPARγ synthetic agonists, which were currently used as insulin-sensitizing agents in the treatment of type 2 diabetes. Although the clinical benefits of thiazolidinediones in treating metabolic disorders have been clearly demonstrated, studies performed in animal models of colitis and in patients with ulcerative colitis have also revealed the key roles of PPARγ activation in the regulation of inflammation and immune response, notably in the colon through epithelial cells.

Intravenous immunoglobulins improve skin fibrosis in experimental models of systemic sclerosis.

Systemic sclerosis (SSc) is the most severe systemic autoimmune disease with currently no cure. Intravenous immunoglobulins (IVIg) are an attractive candidate in this disease to counteract inflammation and fibrosis but data are scarce and conflicting. This study, assessed the effects of IVIg in a murine HOCl-induced model of SSc. We showed that IVIg prevented skin inflammation and fibrosis, by mitigating the immune cell infiltration (p = 0.04), proinflammatory cytokines gene overexpression (IL1ß, p = 0.04; TNFα, p = 0.04; IL6, p = 0.05), skin and dermal thickening (p = 0.003 at d21 and p = 0.0003 at d42), the expression markers of fibrosis, such as αSMA (p = 0.031 for mRNA and p = 0.05 for protein), collagen (p = 0.05 for mRNA and p = 0.04 for protein, p = 0.05 for the hydroxyproline content) and fibronectin (p = 0.033 for mRNA). Moreover, IVIg prevented HOCl-induced alterations in splenic cell homeostasis. When administered in curative mode, despite their ability to reduce skin and dermal thickness (p < 0.0001 and p = 0.0002), IVIg showed partial or more mixed effects on skin inflammation and established fibrosis. These data favor further clinical trials in SSc patients on the potential efficiency of early and/or repeated IVIg administration.

Saccharomyces cerevisiae prevents postoperative recurrence of Crohn's disease modeled by ileocecal resection in HLA-B27 transgenic rats.

BACKGROUND: Postoperative recurrence (POR) after ileocecal resection (ICR) affects most Crohn's disease patients within 3-5 years after surgery. Adherent-invasive Escherichia coli (AIEC) typified by the LF82 strain are pathobionts that are frequently detected in POR of Crohn's disease and have a potential role in the early stages of the disease pathogenesis. Saccharomyces cerevisiae CNCM I-3856 is a probiotic yeast reported to inhibit AIEC adhesion to intestinal epithelial cells and to favor their elimination from the gut. AIM: To evaluate the efficacy of CNCM I-3856 in preventing POR induced by LF82 in an HLA-B27 transgenic (TgB27) rat model. METHODS: Sixty-four rats [strain F344, 38 TgB27, 26 control non-Tg (nTg)] underwent an ICR at the 12th wk (W12) of life and were sacrificed at the 18th wk (W18) of life. TgB27 rats were challenged daily with oral administration of LF82 (109 colony forming units (CFUs)/day (d), n = 8), PBS (n = 5), CNCM I-3856 (109 CFUs/d, n = 7) or a combination of LF82 and CNCM I-3856 (n = 18). nTg rats receiving LF82 (n = 5), PBS (n = 5), CNCM I-3856 (n = 7) or CNCM I-3856 and LF82 (n = 9) under the same conditions were used as controls. POR was analyzed using macroscopic (from 0 to 4) and histologic (from 0 to 6) scores. Luminal LF82 quantifications were performed weekly for each animal. Adherent LF82 and inflammatory/regulatory cytokines were quantified in biopsies at W12 and W18. Data are expressed as the median with the interquartile range. RESULTS: nTg animals did not develop POR. A total of 7/8 (87%) of the TgB27 rats receiving LF82 alone had POR (macroscopic score ≥ 2), which was significantly prevented by CNCM I-3856 administration [6/18 (33%) TgB27 rats, P = 0.01]. Macroscopic lesions were located 2 cm above the anastomosis in the TgB27 rats receiving LF82 alone and consisted of ulcerations with a score of 3.5 (2 - 4). Seven out of 18 TgB27 rats (39%) receiving CNCM I-3856 and LF82 had no macroscopic lesions. Compared to untreated TgB27 animals receiving LF82 alone, coadministration of CNCM I-3856 and LF82 significantly reduced the macroscopic [3.5 (2 - 4) vs 1 (0 - 3), P = 0.002] and histological lesions by more than 50% [4.5 (3.3 - 5.8) vs 2 (1.3 - 3), P = 0.003]. The levels of adherent LF82 were correlated with anastomotic macroscopic scores in TgB27 rats (r = 0.49, P = 0.006), with a higher risk of POR in animals having high levels of luminal LF82 (71.4% vs 25%, P = 0.02). Administration of CNCM I-3856 significantly reduced the levels of luminal and adherent LF82, increased the production of interleukin (IL)-10 and decreased the production of IL-23 and IL-17 in TgB27 rats. CONCLUSION: In a reliable model of POR induced by LF82 in TgB27 rats, CNCM I-3856 prevents macroscopic POR by decreasing LF82 infection and gut inflammation.

Antibody-mediated neutralization of galectin-3 as a strategy for the treatment of systemic sclerosis.

Systemic sclerosis (SSc) is an autoimmune, inflammatory and fibrotic disease with limited treatment options. Developing new therapies is therefore crucial to address patient needs. To this end, we focused on galectin-3 (Gal-3), a lectin known to be associated with several pathological processes seen in SSc. Using RNA sequencing of whole-blood samples in a cross-sectional cohort of 249 patients with SSc, Gal-3 and its interactants defined a strong transcriptomic fingerprint associated with disease severity, pulmonary and cardiac malfunctions, neutrophilia and lymphopenia. We developed new Gal-3 neutralizing monoclonal antibodies (mAb), which were then evaluated in a mouse model of hypochlorous acid (HOCl)-induced SSc. We show that two of these antibodies, D11 and E07, reduced pathological skin thickening, lung and skin collagen deposition, pulmonary macrophage content, and plasma interleukin-5 and -6 levels. Moreover, E07 changed the transcriptional profiles of HOCl-treated mice, resulting in a gene expression pattern that resembled that of control mice. Similarly, pathological pathways engaged in patients with SSc were counteracted by E07 in mice. Collectively, these findings demonstrate the translational potential of Gal-3 blockade as a therapeutic option for SSc.

The PPARγ-dependent effect of flavonoid luteolin against damage induced by the chemotherapeutic irinotecan in human intestinal cells.

Irinotecan (CPT-11) is one of the main agents used to treat colorectal cancer; unfortunately, it is associated with increased intestinal mucositis developing. Luteolin has been shown to prevent damage induced by this chemotherapeutic in mice; thus, in this research, we have investigated luteolin's action mechanism in human intestinal epithelial cells. The potential of luteolin in reducing inflammation and oxidative stress induced by irinotecan in Caco-2 cells was evaluated by PCR through mRNA expression of inflammatory and oxidative genes and by ELISA at the protein level. To assess whether luteolin's ability to control irinotecan-induced damage occurs in a PPARγ dependent manner, experiments were performed on PPARγ downregulated cells. Irinotecan downregulated PPARγ expression and upregulated inflammatory and oxidative genes, while luteolin upregulated PPARγ, HO-1, SOD and decreased expression of IL-1ß and iNOS. Interestingly, when the cells were co-stimulated with luteolin and irinotecan, the flavonoid reversed the inflammation and oxidative imbalance evoked by the chemotherapeutic. However, when these experiments were performed in cells downregulated for PPARγ, luteolin lost the capacity to increase PPARγ and reverse the effect of irinotecan in all tested genes, except by IL-1ß. The present study showed that the protective effect of luteolin against irinotecan is PPARγ dependent.

Soluble markers of B cell activation suggest a role of B cells in the pathogenesis of systemic sclerosis-associated pulmonary arterial hypertension.

Introduction: Soluble markers of B cell activation are interesting diagnostic and prognostic tools in autoimmune diseases. Data in systemic sclerosis (SSc) are scarce and few studies focused on their association with disease characteristics. Methods: 1. Serum levels of 14 B cell biomarkers (ß2-microglobulin, rheumatoid factor (RF), immunoglobulins (Ig) G, IgA, IgM, BAFF, APRIL, soluble (s)TACI, sBCMA sCD21, sCD23, sCD25, sCD27, CXCL13) were measured in SSc patients and healthy controls (HC). 2. Associations between these biomarkers and SSc characteristics were assessed. 3. The pathophysiological relevance of identified associations was explored by studying protein production in B cell culture supernatant. Results: In a discovery panel of 80 SSc patients encompassing the broad spectrum of disease manifestations, we observed a higher frequency of RF positivity, and increased levels of ß2-microglobulin, IgG and CXCL13 compared with HC. We found significant associations between several biomarkers and SSc characteristics related to disease phenotype, activity and severity. Especially, serum IgG levels were associated with pulmonary hypertension (PH); ß2-microglobulin with Nt-pro-BNP and DLCO; and BAFF with peak tricuspid regurgitation velocity (TRV). In a validation cohort of limited cutaneous SSc patients without extensive ILD, we observed lower serum IgG levels, and higher ß2-microglobulin, sBCMA, sCD23 and sCD27 levels in patients with pulmonary arterial hypertension (PAH). BAFF levels strongly correlated with Nt-pro-BNP levels, FVC/DLCO ratio and peak TRV in SSc-PAH patients. Cultured SSc B cells showed increased production of various angiogenic factors (angiogenin, angiopoietin-1, VEGFR-1, PDGF-AA, MMP-8, TIMP-1, L-selectin) and decreased production of angiopoietin-2 compared to HC. Conclusion: Soluble markers of B cell activation could be relevant tools to assess organ involvements, activity and severity in SSc. Their associations with PAH could plead for a role of B cell activation in the pathogenesis of pulmonary microangiopathy. B cells may contribute to SSc vasculopathy through production of angiogenic mediators.

Simple gene signature to assess murine fibroblast polarization.

We provide an original multi-stage approach identifying a gene signature to assess murine fibroblast polarization. Prototypic polarizations (inflammatory/fibrotic) were induced by seeded mouse embryonic fibroblasts (MEFs) with TNFα or TGFß1, respectively. The transcriptomic and proteomic profiles were obtained by RNA microarray and LC-MS/MS. Gene Ontology and pathways analysis were performed among the differentially expressed genes (DEGs) and proteins (DEPs). Balb/c mice underwent daily intradermal injections of HOCl (or PBS) as an experimental murine model of inflammation-mediated fibrosis in a time-dependent manner. As results, 1456 and 2215 DEGs, and 289 and 233 DEPs were respectively found in MEFs in response to TNFα or TGFß1, respectively. Among the most significant pathways, we combined 26 representative genes to encompass the proinflammatory and profibrotic polarizations of fibroblasts. Based on principal component analysis, this signature deciphered baseline state, proinflammatory polarization, and profibrotic polarization as accurately as RNA microarray and LC-MS/MS did. Then, we assessed the gene signature on dermal fibroblasts isolated from the experimental murine model. We observed a proinflammatory polarization at day 7, and a mixture of a proinflammatory and profibrotic polarizations at day 42 in line with histological findings. Our approach provides a small-size and convenient gene signature to assess murine fibroblast polarization.

GED-0507 attenuates lung fibrosis by counteracting myofibroblast transdifferentiation in vivo and in vitro.

The development of more effective, better tolerated drug treatments for progressive pulmonary fibrosis (of which idiopathic pulmonary fibrosis is the most common and severe form) is a research priority. The peroxisome proliferator-activated receptor gamma (PPAR-γ) is a key regulator of inflammation and fibrosis and therefore represents a potential therapeutic target. However, the use of synthetic PPAR-γ agonists may be limited by their potentially severe adverse effects. In a mouse model of bleomycin (BLM)-induced pulmonary fibrosis, we have demonstrated that the non-racemic selective PPAR-γ modulator GED-0507 is able to reduce body weight loss, ameliorate clinical and histological features of pulmonary fibrosis, and increase survival rate without any safety concerns. Here, we focused on the biomolecular effects of GED-0507 on various inflammatory/fibrotic pathways. We demonstrated that preventive and therapeutic administration of GED-0507 reduced the BLM-induced mRNA expression of several markers of fibrosis, including transforming growth factor (TGF)-ß, alpha-smooth muscle actin, collagen and fibronectin as well as epithelial-to-mesenchymal transition (EMT) and expression of mucin 5B. The beneficial effect of GED-0507 on pulmonary fibrosis was confirmed in vitro by its ability to control TGFß-induced myofibroblast activation in the A549 human alveolar epithelial cell line, the MRC-5 lung fibroblast line, and primary human lung fibroblasts. Compared with the US Food and Drug Administration-approved antifibrotic drugs pirfenidone and nintedanib, GED-0507 displayed greater antifibrotic activity by controlling alveolar epithelial cell dysfunction, EMT, and extracellular matrix remodeling. In conclusion, GED-0507 demonstrated potent antifibrotic properties and might be a promising drug candidate for the treatment of pulmonary fibrosis.

Adherent invasive Escherichia coli (AIEC) strain LF82, but not Candida albicans, plays a profibrogenic role in the intestine.

BACKGROUND: Intestinal fibrosis is a frequent complication of Crohn's disease. However, the factors that cause chronicity and promote fibrogenesis are not yet understood. AIMS: In the present study, we evaluated the profibrotic effects of adherent-invasive Escherichia coli (AIEC) LF82 strain and Candida albicans in the gut. METHODS: Colonic fibrosis was induced in C57BL/6 mice by administration of three cycles of 2.5% (w/v) dextran sulfate sodium (DSS) for 5 weeks. LF82 and C. albicans were administered orally once at the start of each week or each cycle, respectively. Expression of markers of myofibroblast activation was determined in TGF-ß1-stimulated human intestinal epithelial cells (IECs). RESULTS: LF82 administration exacerbated fibrosis in DSS-treated mice, revealed by increased colonic collagen deposition and expression of the profibrotic genes Col1a1, Col3a1, Fn1 and Vim. This was accompanied by enhanced gene expression of proinflammatory cytokines and chemokines, as well as more recruited inflammatory cells into the intestine. LF82 also potentiated TGF-ß1-stimulated epithelial-mesenchymal transition and myofibroblast activation in IECs, by further inducing gene expression of the main mesenchymal cell markers FN1 and VIM and downregulating the IEC marker OCLN. Proinflammatory cytokines were overexpressed with LF82 in TGF-ß1-stimulated IECs. Conversely, C. albicans did not affect intestinal fibrosis progression in DSS-treated mice or myofibroblast activation in TGF-ß1-stimulated IECs. CONCLUSIONS: These results demonstrate that AIEC strain LF82, but not C. albicans, may play a major profibrogenic role in the gut.

Intracellular molecular effects of insulin resistance in patients with metabolic syndrome.

AIM OF THE STUDY: Patients with metabolic syndrome (MetS) have an increased risk of cardiovascular disease. Data obtained from muscle biopsies have demonstrated altered insulin signaling (IS) in patients with MetS. The IS regulates critical cell functions including molecular-regulated cellular metabolite fluxes, protein and energetic metabolism, cell proliferation and apoptosis with consequent regulation of cell life including endothelial homeostasis and blood coagulation. However, little is known about blood cell IS in MetS patients. The aim of this study was to develop a method to evaluate IS in peripheral lymphocytes to identify altered intracellular molecules in patients with MetS to use as risk biomarkers of vascular thrombosis. PATIENTS AND METHODS: We investigated 40 patients with MetS and 20 controls. MetS was defined according to guidelines from the US National Cholesterol Education Program Adult Treatment Panel III. Blood samples were taken from all participants. Total mononuclear cells were isolated from peripheral blood using density gradient centrifugation. IS molecules were evaluated using Western blot analysis followed by computer-assisted densitometer evaluation. RESULTS: Lymphocytes of MetS patients showed a reduced mTOR expression (the mammalian target of rapamycin) which is a fundamental molecule of IS. Major impairment of IS was confirmed by reduced upstream and downstream mTOR molecules which regulate fundamental cells metabolic functions. CONCLUSIONS: In patients with MetS, we found a reduction of mTOR and other mTOR-related molecules involved in insulin resistance, cell repair, coagulation and vasculogenesis. A reduced expression of mTOR may reflect an increased risk of vascular thrombosis.

Luteolin prevents irinotecan-induced intestinal mucositis in mice through antioxidant and anti-inflammatory properties.

BACKGROUND AND PURPOSE: Intestinal mucositis refers to mucosal damage caused by cancer treatment, and irinotecan is one of the agents most associated with this condition. Focusing on the development of alternatives to prevent this important adverse effect, we evaluated the activity of the flavonoid luteolin, which has never been tested for this purpose despite its biological potential. EXPERIMENTAL APPROACH: The effects of luteolin were examined on irinotecan-induced intestinal mucositis in mice. Clinical signs were evaluated. Moreover, histological, oxidative, and inflammatory parameters were analysed, as well as the possible interference of luteolin in the anti-tumour activity of irinotecan. KEY RESULTS: Luteolin (30 mg·kg-1 ; p.o. or i.p.) prevented irinotecan-induced intestinal damage by reducing weight loss and diarrhoea score and attenuating the shortening of the duodenum and colon. Histological analysis confirmed that luteolin (p.o.) prevented villous shortening, vacuolization, and apoptosis of cells and preserved mucin production in the duodenum and colon. Moreover, luteolin treatment mitigated irinotecan-induced oxidative stress, by reducing the levels of ROS and LOOH and augmenting endogenous antioxidants, and inflammation by decreasing MPO enzymic activity, TNF, IL-1ß, and IL-6 levels and increasing IL-4 and IL-10. Disruption of the tight junctions ZO-1 and occludin was also prevented by luteolin treatment. Importantly, luteolin did not interfere with the anti-tumour activity of irinotecan. CONCLUSION AND IMPLICATIONS: Luteolin prevents intestinal mucositis induced by irinotecan and therefore could be a potential adjunct in anti-tumour therapy to control this adverse effect, increasing treatment adherence and consequently the chances of cancer remission.

Arachidonic acid modulates the crosstalk between prostate carcinoma and bone stromal cells.

Diets high in n-6 fatty acids are associated with an increased risk of bone metastasis from prostate carces (PCa). The molecular mechanism underlying this phenomenon is largely unknown. Arachidonic acid (AA) and its precursor linoleic acid can be metabolized to produce pro-inflammatory cytokines that act as autocrine and paracrine regulators of cancer behavior. We and other authors have previously reported that factors released by PCa cells excite an aberrant response in bone marrow stromal cells (BMSCs). We planned to study how AA may modulate in vitro the interaction between PCa cells and human BMSCs. First, we observed that AA is a potent mitogenic factor for PCa cells through the production of both 5-lipoxygenase (5-LOX) and cyclooxygenase-2 (COX-2) metabolites. While 5-LOX controls cell survival through the regulation of the Bcl-2/Bax ratio, COX-2 activity stimulates the release of transforming growth factor-alpha (TGF-alpha) and pro-inflammatory cytokines. The blockade of COX-2 activity through a specific inhibitor is sufficient to repress AA-induced gene transcription. The over-expression of transforming growth factor -alpha (TGF-alpha), tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1beta) by AA-primed PCa cells resulted particularly effective in modifying cell behavior of cultured human BMSCs. In fact, we observed an increment in the cell number of BMSCs, due prevalently to the action of TGF-alpha, the number of osteoblasts, and the production of receptor activator for nuclear factor kappa B ligand (RANKL), events mainly controlled by inflammatory cytokines. These findings provide a possible molecular mechanism by which dietary n-6 fatty acids accumulating in bone marrow may influence the formation of PCa-derived metastatic lesions and indicate new molecular targets for the therapy of metastatic PCa.

Angiotensin receptor blockers improve insulin signaling and prevent microvascular rarefaction in the skeletal muscle of spontaneously hypertensive rats.

OBJECTIVE: Spontaneously hypertensive rats are an example of an animal model of genetic hypertension with insulin resistance. The aim of this study was to investigate insulin signaling in the heart and in the skeletal muscle of spontaneously hypertensive rats, as well as to evaluate the effects of renin-angiotensin system blockade. DESIGN AND METHODS: We investigated eight untreated spontaneously hypertensive rats of 12 weeks of age and eight age-matched normotensive Wistar-Kyoto controls. In addition, eight spontaneously hypertensive rats were treated for 8 weeks with the angiotensin receptor blocker olmesartan, and eight spontaneously hypertensive rats with the angiotensin-converting enzyme inhibitor enalapril. The heart and a skeletal muscle (quadriceps femoris) were promptly dissected and frozen. Insulin signaling was evaluated by Western blot analysis of involved proteins; in addition, microvessel density was indirectly evaluated by immunohistochemistry. RESULTS: Blood pressure values were normalized by both olmesartan and enalapril. In the heart, no statistically significant difference in the expression of proteins involved in insulin signaling was observed between untreated spontaneously hypertensive rats and Wistar-Kyoto controls. On the contrary, in the skeletal muscle of untreated spontaneously hypertensive rats, we noted a significant reduction of insulin receptors, of insulin-receptor substrate-1, and of phosphorylated-mammalian target of rapamycin. The treatment with olmesartan normalized insulin signaling, including expression of glucose transporter-4, whereas the treatment with enalapril was ineffective for the insulin receptor and less effective than olmesartan on the insulin-receptor substrate-1, phosphorylated-mammalian target of rapamycin and glucose transporter-4. There was a significant reduction in microvessel density in the skeletal muscle of spontaneously hypertensive rats compared with Wistar-Kyoto controls, and this was completely prevented by both olmesartan and enalapril. CONCLUSION: These results suggest that changes in insulin signaling occur in the skeletal muscle but not in the heart of untreated spontaneously hypertensive rats. In the skeletal muscle, insulin signaling was restored by olmesartan, whereas enalapril was less effective. Effective antihypertensive treatment with olmesartan or enalapril was associated with prevention of microvascular rarefaction.

Intracellular mechanisms of metabolism regulation: the role of signaling via the mammalian target of rapamycin pathway and other routes.

The development of diabetes mellitus is the consequence of defects in the action of insulin in skeletal muscles and adipose tissue other than pancreas and liver defects. Insulin action defects are mostly the results of defects of the insulin intracellular signaling transduction pathway. This review summarizes the main mechanisms involved in insulin signaling and possible intracellular defects that lead to insulin resistance. We also report preliminary experimental data that suggest the existence of intracellular alternatives to insulin metabolic pathways stimulated by nutrients such as amino acids (AAs). Indeed, we found that oral supplements with AAs stimulated both glucose transporter-4 and protein synthesis through independent insulin signals in rat hearts. Evidence suggests that the mammalian target of rapamycin and/or other molecules could be involved in this insulin-independent metabolic pathway. This hypothesis suggests the presence of an ancestral metabolic pathway in eukaryotic cells that is not active when insulin intracellular signaling is efficient but can be activated by alternative stimuli, such as AAs, when insulin signaling is impaired. Our observations provide molecular evidence that supports the use of anabolic nutrients such as AAs, together with standard therapies, to overcome insulin resistance syndrome.

Interaction between sphingosine kinase/sphingosine 1 phosphate and transforming growth factor-ß/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-ß/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-ß/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-ß, 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.

Tyrosine kinase inhibitor CEP-701 blocks the NTRK1/NGF receptor and limits the invasive capability of prostate cancer cells in vitro.

In the prostate, cellular growth and differentiation are finely regulated by a complex interaction between stromal and epithelial cells under the control of both autocrine and paracrine regulatory factors such as the nerve growth factor (NGF). However, the role of NGF and its receptors including the high-affinity p-140 TrkA and the low-affinity p75 NTR receptors remains controversial. Moreover prostate tissues stored other neutrophins such as NT3, NT4 and brain derived neutrophic factor (BDNF) as well as the corresponding receptors (NTRs). Different members of NTRs are expressed during prostate cancer (PCa) progression, suggesting their involvement in cell proliferation, anoikis protection and malignancy. Therefore, we analyzed the expression of NTRs including NTRK1 (TrkA), NTRK2 (TrkB), NTRK3 (TrkC) and p75 NGFR in a panel of 7 well-characterized PCa cell lines and 12 cell derivatives from PC3 (4), DU145 (2), CWR22R (4) and LnCap (2) cell lines possessing different proliferative/invasive capabilities. We evaluated also the role of NGF, BDNF and NT3 in the modulation of cell migration and invasion and, finally, the effects of a pan Trk inhibitor, CEP-701 which has been included in some clinical trials for the treatment of PCa. We observed the following: i) TrkA and TrkB expression was significantly higher in AR-negative compared to AR-positive cells; ii) TrkA and TrkB expression was related to the invasive capacity/malignancy of PCa cells; iii) p75 NGFR could be considered a tumor suppressor gene which is present at high levels only in AR-positive cells; and iv) that NGF and BDNF (targeting TrkA/p75 NTR and TrKB, respectively) induced cell migration and this was inhibited by the CEP-701 treatment. In conclusion, the malignancy of PCa seems to be accompanied by increased TrkA and TrkB signaling (with a reduction of p75 NGFR expression) and CEP-701 could be used to reduce the metastasis formation in advanced PCa. CEP-701 is a trademark of Cephalon Inc., West Chester, PA, USA.