Galectin-3 regulates inflammasome activation in cholestatic liver injury

Macrophage activation is an important feature of primary biliary cholangitis (PBC) pathogenesis and other cholestatic liver diseases. Galectin-3 (Gal3), a pleiotropic lectin, is produced by monocytic cells and macrophages. However, its role in PBC has not been addressed. We hypothesized that Gal3 is a key to induce NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome in macrophages and in turn to propagate proinflammatory IL-17 signaling. In liver tissues from patients with PBC and dnTGF-βRII mice, a model of autoimmune cholangitis, the expression of Gal3, NLRP3, and the adaptor protein adaptor apoptosis-associated speck-like protein was induced, with the downstream activation of caspase-1 and IL-1β. In wild-type hepatic macrophages, deoxycholic acid induced the association of Gal3 and NLRP3 with direct activation of the inflammasome, resulting in an increase in IL-1β. Downstream retinoid-related orphan receptor C mRNA, IL-17A, and IL-17F were induced. In Gal3-/- macrophages, no inflammasome activation was detected. To confirm the key role of Gal3 in the pathogenesis of cholestatic liver injury, we generated dnTGF-βRII/galectin-3-/- (dn/Gal3-/-) mice, which showed impaired inflammasome activation along with significantly improved inflammation and fibrosis. Taken together, our data point to a novel role of Gal3 as an initiator of inflammatory signaling in autoimmune cholangitis, mediating the activation of NLRP3 inflammasome and inducing IL-17 proinflammatory cascades. These studies provide a rationale to target Gal3 in autoimmune cholangitis and potentially other cholestatic diseases.-Tian, J., Yang, G., Chen, H.-Y., Hsu, D. K., Tomilov, A., Olson, K. A., Dehnad, A., Fish, S. R., Cortopassi, G., Zhao, B., Liu, F.-T., Gershwin, M. E., Török, N. J., Jiang, J. X. Galectin-3 regulates inflammasome activation in cholestatic liver injury.

Information technology acceptance in health information management

OBJECTIVE

User acceptance of information technology has been a significant area of research for more than two decades in the field of information technology. This study assessed the acceptance of information technology in the context of Health Information Management (HIM) by utilizing Technology Acceptance Model (TAM) which was modified and applied to assess user acceptance of health information technology as well as viability of TAM as a research construct in the context of HIM.

METHODS

This was a descriptive- analytical study in which a sample of 187 personnel from a population of 363 personnel, working in medical records departments of hospitals affiliated to Tehran University of Medical Sciences, was selected. Users' perception of applying information technology was studied by a researcher-developed questionnaire. Collected data were analyzed by SPSS software (version16) using descriptive statistics and regression analysis.

RESULTS

The results suggest that TAM is a useful construct to assess user acceptance of information technology in the context of HIM. The findings also evidenced the perceived ease of use (PEOU) and perceived usefulness (PE) were positively associated with favorable users' attitudes towards HIM. PU was relatively more associated (r= 0.22, p = 0.05) than PEOU (r = 0.014, p = 0.05) with favorable user attitudes towards HIM.

CONCLUSIONS

Users' perception of usefulness and ease of use are important determinants providing the incentive for users to accept information technologies when the application of a successful HIM system is attempted. The findings of the present study suggest that user acceptance is a key element and should subsequently be the major concern of health organizations and health policy makers.

AGER1 downregulation associates with fibrosis in nonalcoholic steatohepatitis and type 2 diabetes

Type 2 diabetes is clinically associated with progressive necroinflammation and fibrosis in nonalcoholic steatohepatitis (NASH). Advanced glycation end-products (AGEs) accumulate during prolonged hyperglycemia, but the mechanistic pathways that lead to accelerated liver fibrosis have not been well defined. In this study, we show that the AGEs clearance receptor AGER1 was downregulated in patients with NASH and diabetes and in our NASH models, whereas the proinflammatory receptor RAGE was induced. These findings were associated with necroinflammatory, fibrogenic, and pro-oxidant activity via the NADPH oxidase 4. Inhibition of AGEs or RAGE deletion in hepatocytes in vivo reversed these effects. We demonstrate that dysregulation of NRF2 by neddylation of cullin 3 was linked to AGER1 downregulation and that induction of NRF2 using an adeno-associated virus-mediated approach in hepatocytes in vivo reversed AGER1 downregulation, lowered the level of AGEs, and improved proinflammatory and fibrogenic responses in mice on a high AGEs diet. In patients with NASH and diabetes or insulin resistance, low AGER1 levels were associated with hepatocyte ballooning degeneration and ductular reaction. Collectively, prolonged exposure to AGEs in the liver promotes an AGER1/RAGE imbalance and consequent redox, inflammatory, and fibrogenic activity in NASH.

Nonphagocytic Activation of NOX2 Is Implicated in Progressive Nonalcoholic Steatohepatitis During Aging

BACKGROUND AND AIMS

Older patients with obesity/type II diabetes mellitus frequently present with advanced NASH. Whether this is due to specific molecular pathways that accelerate fibrosis during aging is unknown. Activation of the Src homology 2 domain-containing collagen-related (Shc) proteins and redox stress have been recognized in aging; however, their link to NASH has not been explored.

APPROACH AND RESULTS

Shc expression increased in livers of older patients with NASH, as assessed by real time quantitative PCR (RT-qPCR) or western blots. Fibrosis, Shc expression, markers of senescence, and nicotinamide adenine dinucleotide phosphate, reduced form oxidases (NOXs) were studied in young/old mice on fast food diet (FFD). To inhibit Shc in old mice, lentiviral (LV)-short hairpin Shc versus control-LV were used during FFD. For hepatocyte-specific effects, floxed (fl/fl) Shc mice on FFD were injected with adeno-associated virus 8-thyroxine-binding globulin-Cre-recombinase versus control. Fibrosis was accelerated in older mice on FFD, and Shc inhibition by LV in older mice or hepatocyte-specific deletion resulted in significantly improved inflammation, reduction in senescence markers in older mice, lipid peroxidation, and fibrosis. To study NOX2 activation, the interaction of p47^phox (NOX2 regulatory subunit) and p52Shc was evaluated by proximity ligation and coimmunoprecipitations. Palmitate-induced p52Shc binding to p47^phox , activating the NOX2 complex, more so at an older age. Kinetics of binding were assessed in Src homology 2 domain (SH2) or phosphotyrosine-binding (PTB) domain deletion mutants by biolayer interferometry, revealing the role of SH2 and the PTB domains. Lastly, an in silico model of p52Shc/p47^phox interaction using RosettaDock was generated.

CONCLUSIONS

Accelerated fibrosis in the aged is modulated by p52Shc/NOX2. We show a pathway for direct activation of the phagocytic NOX2 in hepatocytes by p52Shc binding and activating the p47^phox subunit that results in redox stress and accelerated fibrosis in the aged.

Development of immune-biomarkers of pulmonary tuberculosis in a rabbit model

Tuberculosis (TB) causes extensive morbidity and mortality worldwide with approximately 10 million new cases of active disease emerging mostly from a pool of two billion individuals latently infected with Mycobacterium tuberculosis (M. tb) every year. The underlying host immune responses that drive M. tb infection to active disease or latency are not well understood. We propose that identification and characterization of host immune biomarkers will be helpful to better understand the mechanisms that drive this process, and may, in addition, lead to the development of better diagnostic tools for TB. We have previously reported the profiles of plasma immune biomarkers in pulmonary TB patients in endemic countries, and in M. tb-infected nonhuman primates. However, biomarker profiling for a cost-effective and user-friendly animal model relevant to human disease, such as rabbit, has not been developed. One challenge in the analysis of circulating cytokines/chemokines for rabbit model of TB is the limited availability of validated immune-reagents. Here we report the use of a commercially available multiplex microbead human cytokine/chemokine panels as development platform for rabbit immune reagents. The results demonstrate their utility to determine circulating analytes and define their profiles related to TB in the rabbit model. In addition, we report the profiles of circulating anti-M. tb antibodies in the plasma of rabbits with active pulmonary TB. These studies show that the pattern of expression of circulating immune biomarkers correlate with TB pathology in rabbits, and are similar to those defined in pulmonary TB patients.