Anna Maria Zambito

Chitotriosidase and inflammatory mediator levels in Alzheimer's disease and cerebrovascular dementia

Inflammation has been reported to be involved in the pathogenesis of cerebrovascular dementias (CvDs). This study investigated the involvement of Chitotriosidase (ChT), a chinolitic enzyme mainly produced by activated macrophages, in the pathophysiology of Alzheimers disease (AD) and ischemic CvD. In addition, the levels of interleukin (IL)‐16, IL‐18, transforming growth factor (TGF) ‐β1 and superoxide anion (O2–) were determined to evaluate the relationship between ChT levels, these cytokines and oxidative stress in both AD and ischemic CvD patients. The levels of ChT and IL‐16, IL‐18, and TGF‐β1 mRNA were investigated using quantitative real‐time polymerase chain reaction on macrophages of peripheral blood of 40 patients with AD, 40 patients with ischemic CvD and 40 non‐demented age‐matched subjects. The results show that ChT, IL‐16 and O2– levels significantly increased in ischemic CvD patients compared with AD patients and were significantly and positively correlated with IL‐18 and O2–. The production of IL‐18 was increased in both AD and ischemic CvD patients. TGF‐β1 expression was higher in AD patients and was inversely correlated with the expression of ChT, IL‐16 and IL‐18, respectively. In non‐demented age‐matched subjects no significant changes in ChT and IL‐16, IL‐18, and TGF‐β1 expression were found. Our results indicate that ChT, IL‐16, IL‐18 and TGF‐β1 are increased in ischemic CvD and AD, confirming that the immune system may play an important role in the development and progression of neurodegenerative disorders. In addition, the present findings suggest that ChT could also play a crucial role in pathological conditions such as CvD in which the inflammatory process is activated.

Chitotriosidase gene expression in Kupffer cells from patients with non-alcoholic fatty liver disease

Background and aims: Non-alcoholic steatohepatitis (NASH) is a clinicopathological condition characterised by a necroinflammatory disorder with fatty infiltration of the hepatocytes. The molecular mechanisms involved in the anomalous behaviour of liver cells have only partially been determined. Human chitotriosidase (Chit) is a chitinolytic enzyme mainly produced by activated macrophages. The aim of this study was to investigate the expression of the chitinase-like gene in Kupffer cells, to determine how chitotriosidase may be implicated in the progression from uncomplicated steatosis to steatohepatitis with progressive fibrosis. Methods: 75 subjects were studied: 40 with NASH, 20 with simple steatosis, and 15 normal controls. Kupffer cells obtained from liver biopsies were used to detect CHIT expression, superoxide anion (O2−), lipid peroxidation, and tumour necrosis factor α (TNFα) and ferritin levels. Results: CHIT expression differed markedly in livers from normal controls and in those from patients with simple steatosis or non-alcoholic steatohepatitis. A significant correlation between mRNA CHIT and O2−, lipid peroxidation, TNFα, and ferritin levels was observed in both NASH and simple steatosis. Conclusions: Human Kupffer cells in NASH patients overproduce chitotriosidase. At the highest levels of production, this enzyme may play a role in increasing the risk for a poor outcome in steatohepatitis.

Potential Role of Chitotriosidase Gene in Nonalcoholic Fatty Liver Disease Evolution

BACKGROUND:Nonalcoholic steatohepatitis (NASH) is a liver disease characterized by steatosis and periportal and lobular inflammation. The molecular mechanisms involved in the anomalous behavior of liver cells have only partially been disclosed. Human Chitotriosidase (Chit) is a member of the chitinase family that it is mainly synthesized by activated macrophages. We investigated chitotriosidase gene expression in Kupffer cells to determine the potential implication of this enzyme in the inflammation and in the progression from uncomplicated steatosis to steatohepatitis with progressive fibrosis.METHODS:Seventy-five liver biopsies from 40 subjects with NASH, 20 with simple steatosis, and 15 controls were used to detect CHIT expression, tumor necrosis factor-alpha (TNF-α), alpha-smooth muscle actin (α-SMA), and lipid peroxidation.RESULTS:CHIT was expressed exclusively by Kupffer cells. The levels of CHIT expression were significantly higher in NASH patients than in simple steatosis patients and in the control group. In addition, we found that CHIT over-expression influenced hepatic stellate cells activation, as demonstrated by the significant correlation between CHIT and α-SMA expression in NASH patients. A significant correlation was observed also between CHIT, TNF-α and lipid peroxidation in both NASH and simple steatosis.CONCLUSION:These results suggest that CHIT over-produced by Kupffer cells may contribute to the progression of hepatic fibrosis.

Prolactin induces chitotriosidase expression in human macrophages through PTK, PI3‐K, and MAPK pathways

We previously reported that prolactin (PRL) induces chitotriosidase (CHIT‐1) mRNA expression in human macrophages. In this investigation we determined the signaling pathways involved in CHIT‐1 induction in response to PRL. The CHIT‐1 induction PRL‐mediated was reduced by wortmannin and LY‐294002, inhibitors of phosphatidylinositol 3‐kinase (PI3‐K) and by genistein an inhibitor of protein tyrosine kinase (PTK). Pre‐treatment of macrophages with SB203580, a specific inhibitor of the mitogen‐activated kinases (MAPK) p38, or with U0126, an inhibitor of MAPK p44/42, prevented both basal and exogenous PRL‐mediated CHIT‐1 expression. No significant effects on CHIT‐1 induction PRL‐mediated were observed with a protein kinase C inhibitor (PKC), rottlerin, or with an Src inhibitor, PP2, or with JAK2 inhibitor, AG490. In addition, PRL induced a phosphorylation of AKT that was prevented both by the two MAPK inhibitors SB203580 and U0126 and by the PI3‐K inhibitors wortmannin and LY‐294002. In conclusion, our results indicate that PRL up‐regulated CHIT‐1 expression via PTK, PI3‐K, MAPK, and signaling transduction components. J. Cell. Biochem. 107: 881–889, 2009.

FRTL-5 experiment during ENEIDE mission

The FRTL-5 experiment was performed during the 10 day Italian Soyuz Mission “ENEIDE” (from April 15 to April 25, 2005) on the International Space Station. The main objectives were: 1) the validation of the FRTL5 cells as a biological system to evaluate space environment effects; 2) the investigation of the space environment-related pathophysiological mechanisms of cellular damage and/or behaviour; 3) to verify if fastgrowing cells could be differently sensitive to space environment-related effects as compared to cells in physiological standby. Because of the limited available space in the dedicated facilities and the restrictive requirements imposed by ESA, RSA and NASA, and because no pre-qualified equipment existed, all of the equipment and the procedures have been subjected to structural failure test and to severe qualification tests. Results were: 1) all the qualification procedures and tests were successful 2) Overall cell number is lower in the cultures exposed to space environment as compared to the controls reproducing the temperature conditions during the ENEIDE mission; 3) This phenomenon is most likely related to a slower growth rate in proliferative state; 4) This slow growth rate is: a) reversible, as demonstrated by the results of the growth curves, the plating and cloning efficiencies measured on the samples once they have been returned to our laboratory in Udine; b) mostly related to space effects as indicated by additional control in a clinostat. More experiments of this kind are needed to verify and validate these data and to investigate the molecular mechanisms underling the phenomenon.