[Effect of pyroptosis in the pathogenesis of alcoholic liver disease].

Long-term intake of large amounts of ethanol leads to enterogenous endotoxemia. Reactive oxygen species, high concentrations of adenosine triphosphate and uric acid activate the pyroptosis system, which then cleaves the pore formation mechanism of gasdermin-D, leading to the death of liver cells, accompanied by the release of interleukin-1ß, interleukin-18, and other inflammatory factors. This series of processes activates the immune system, mediates a cascade of inflammation, and promotes the development of alcoholic liver disease from steatosis to inflammation and fibrosis.

Effect of the Fusarium toxins, zearalenone and deoxynivalenol, on the mouse brain.

The aim of this study was to find effects of Fusarium toxins on brain injury in mice. We evaluated the individual and combined effect of the Fusarium toxins zearalenone and deoxynivalenol on the mouse brain. We examined brain weight, protein, antioxidant indicators, and apoptosis. After 3 and 5days of treatment, increased levels of nitric oxide, total nitric oxide synthase, hydroxyl radical scavenging, and malondialdehyde were observed in the treatment groups. This was accompanied by reduced levels of brain protein, superoxide dismutase (apart from the low-dose zearalenone groups), glutathione, glutathione peroxidase activity, and percentage of apoptotic cells. By day 12, most of these indicators had returned to control group levels. The effects of zearalenone and deoxynivalenol were dose-dependent, and were synergistic in combination. Our results suggest that brain function is affected by zearalenone and deoxynivalenol.

Evaluation of the direct nitrate reductase assay for rapid detection of extensively drug-resistant tuberculosis.

SETTING: Jiangxi, China. OBJECTIVE: To evaluate the performance of the direct nitrate reductase assay (D-NRA) for rapid, low-cost detection of multidrug-resistant (MDR-) and extensively drug-resistant tuberculosis (XDR-TB) in high-burden, resource-limited settings. METHODS: A total of 225 smear-positive sputum samples were collected from consecutive drug-resistant TB subjects. Samples were processed at the Province TB Reference Laboratory and tested for susceptibility to rifampicin (RMP), isoniazid (INH), ofloxacin (OFX), kanamycin (KM) and capreomycin (CPM) by D-NRA, using the indirect Löwenstein-Jensen proportion method (LJ-PM) as reference. RESULTS: Of the 225 smear-positive sputum samples, 214 isolates were identified as Mycobacterium tuberculosis and analysed for further comparison. The sensitivity of the D-NRA in the detection of resistance to RMP, INH, OFX, KM and CPM was respectively 95.1% (97/102), 93.1% (135/145), 97.4% (76/78), 88.9% (40/45) and 90.6% (29/32); specificity was respectively 100% (112/112), 97.1% (67/69), 100% (136/136), 98.8% (167/169) and 96.7% (176/182). The median time to culture positivity was significantly shorter for NRA than for the indirect LJ-PM (14 days vs. 70 days, P < 0.001). CONCLUSION: D-NRA showed high sensitivity and specificity in the rapid diagnosis of MDR- and XDR-TB in a high-burden, resource-limited setting.

Thrombin Activates Latent TGFß1 via Integrin αvß1 in Gingival Fibroblasts.

Transforming growth factor ß (TGFß) regulates cell proliferation, differentiation, migration, apoptosis, and extracellular matrix production. It also plays a pivotal role in the pathogenesis of gingival overgrowth. Thrombin is a key player in tissue repair, remodeling, and fibrosis after an injury, and it exerts profibrotic effects by activating protease-activated receptors. Connective tissue growth factor (CTGF or CCN2) modulates cell adhesion, migration, proliferation, matrix production, and wound healing. It is overexpressed in many fibrotic disorders, including gingival overgrowth, and it is positively associated with the degree of fibrosis in gingival overgrowth. In human gingival fibroblasts, we previously found that TGFß1 induced CCN2 protein synthesis through c-jun N-terminal kinase and Smad3 activation. Thrombin stimulates CCN2 synthesis through protease-activated receptor 1 and c-jun N-terminal kinase signaling. Curcumin inhibited TGFß1- and thrombin-induced CCN2 synthesis. In this study, we demonstrated that thrombin and protease-activated receptor 1 agonist SFLLRN induced latent TGFß1 activation and Smad3 phosphorylation in human gingival fibroblasts. Pretreatment with a TGFß-neutralizing antibody, TGFß type I receptor inhibitor SB431542, and Smad3 inhibitor SIS3 inhibited approximately 86%, 94%, and 100% of thrombin-induced CCN2 synthesis, respectively. Furthermore, blocking integrin subunits αv and ß1 with antibodies effectively inhibited SFLLRN-induced Smad3 phosphorylation and CCN2 synthesis and increased activated TGFß1 levels; however, similar effects were not observed for integrins αvß3 and αvß5. These results suggest that protease-activated receptor 1-induced CCN2 synthesis in human gingival fibroblasts is mediated through integrin αvß1-induced latent TGFß1 activation and subsequent TGFß1 signaling. Moreover, curcumin dose dependently decreased thrombin-induced activated TGFß1 levels. Curcumin-inhibited thrombin-induced CCN2 synthesis in human gingival fibroblasts is caused by the suppression of latent TGFß1 activation.

NADPH Oxidase 4 Mediates TGFß1-induced CCN2 in Gingival Fibroblasts.

Transforming growth factor ß (TGFß) plays a central role in the pathogenesis of gingival overgrowth (GO). Connective tissue growth factor (CTGF; or CCN2) is induced by TGFß in human gingival fibroblasts (HGFs) and is overexpressed in GO tissues. CCN2 creates an environment favorable for fibrogenesis and is required for the maximal profibrotic effects of TGFß. We previously showed that Src, JNK, and Smad3 mediate TGFß1-induced CCN2 protein expression in HGFs. Moreover, Src is an upstream signaling transducer of JNK and Smad3. Recent studies suggested that NADPH oxidase (NOX)-dependent redox mechanisms are involved in mediating the profibrotic effects of TGFß. In this study, we demonstrated that TGFß1 upregulated NOX4 protein expression and increased reactive oxygen species (ROS) production in HGFs. Genetic or pharmacologic targeting of NOX4 abrogated TGFß1-induced ROS production; Src, JNK, and Smad3 activation; and CCN2 and type I collagen protein expression in HGFs. Our results indicated that NOX4-derived ROS play pivotal roles in activating Src kinase activity leading to the activation of canonical (Smad3) and noncanonical (JNK) cascades that cooperate to attain maximum CCN2 expression. Furthermore, we demonstrated that curcumin significantly inhibited the TGFß1-induced NOX4 protein expression in HGFs. Curcumin potentially qualifies as an agent to control GO by suppressing TGFß1-induced NOX4 expression in HGFs.

Curcumin inhibits TGFß1-induced CCN2 via Src, JNK, and Smad3 in gingiva.

Transforming growth factor ß (TGFß) is a key regulator associated with the pathogenesis of gingival overgrowth (GO). Connective tissue growth factor (CTGF/CCN2) is overexpressed in GO tissues. CCN2 promotes and sustains fibrosis initiated by TGFß. Previous studies have shown that JNK and Smad3 activation is required for TGFß-induced CCN2 expressions in human gingival fibroblasts (HGFs). In this study, we have found that Src is a major signaling mediator for TGFß-induced CCN2 expressions in HGFs. Pre-treatment with 2 Src kinase inhibitors (PP2, Src inhibitor-1) significantly reduced TGFß1-induced CCN2 synthesis and JNK and Smad3 activation in HGFs. These results suggest that Src is an upstream signaling transducer of JNK and Smad3 with respect to TGFß1-stimulated CCN2 expression in HGFs. We further found that curcumin significantly abrogated the TGFß1-induced CCN2 in HGFs by inhibiting the phosphorylations of Src, JNK, and Smad3. Furthermore, curcumin inhibited TGFß1-induced HGF migration and α-SMA expression. Curcumin potentially qualifies as a useful agent for the control of GO.