The interaction between T cell immunoglobulin-and mucin-domain-containing molecule (Tim-3) expressed on T helper 1 (Th1) cells, and its ligand, galectin-9, negatively regulates Th1-mediated immune responses. However, it is poorly understood if and how the Tim-3/ galectin-9 signaling pathway is involved in immune escape in patients with hepatocellular carcinoma (HCC). Here we studied the expression, function, and regulation of the Tim-3/ galectin-9 pathway in patients with hepatitis B virus (HBV)-associated HCC. We detected different levels of galectin-9 expression on antigen-presenting cell (APC) subsets including Kupffer cells (KCs), myeloid dendritic cells (DCs), and plasmacytoid DCs in HCC. The highest galectin-9 expression was on KCs in HCC islets, not in the adjacent tissues. Furthermore, Tim-3 expression was increased on CD4 1 and CD8 1 T cells in HCC as compared to the adjacent tissues, and Tim-3 1 T cells were replicative senescent and expressed surface and genetic markers for senescence. Interestingly, tumor-infiltrating T-cell-derived interferon (IFN)-c stimulated the expression of galectin-9 on APCs in the HCC microenvironment. Immunofluorescence staining revealed a colocalization of Tim-3 1 T cells and galectin-91 KCs in HCC. Functional studies demonstrated that blockade of the Tim-3/ galectin-9 signaling pathway importantly increased the functionality of tumor-infiltrating Tim-3 1 T cells as shown by increased T-cell proliferation and effector cytokine production. Finally, we show that the numbers of Tim-3 1 tumor-infiltrating cells were negatively associated with patient survival. Conclusion: Our work demonstrates that the Tim-3/galectin-9 signaling pathway mediates T-cell senescence in HBV-associated HCC. The data suggest that this pathway could be an immunotherapeutic target in patients with HBV-associated HCC. (HEPATOLOGY 2012;56:1342-1351 H epatocellular carcinoma (HCC) is one of the most common cancers. More than 80% of patients are not candidates for curative treatments with the final diagnosis, and are linked to chronic infection with the hepatitis B (HBV) or hepatitis C (HCV) viruses based on different regions.

The alpine treeline is commonly regarded as being sensitive to climatic warming because regeneration and growth of trees at treeline generally are limited by low temperature. The alpine treelines of the Tibetan Plateau (TP) occur at the highest elevations (4,900 m above sea level) in the Northern Hemisphere. Ongoing climatic warming is expected to shift treelines upward. Studies of treeline dynamics at regional and local scales, however, have yielded conflicting results, indicating either unchanging treeline elevations or upward shifts. To reconcile this conflict, we reconstructed in detail a century of treeline structure and tree recruitment at sites along a climatic gradient of 4°C and mean annual rainfall of 650 mm on the eastern TP. Species interactions interacted with effects of warming on treeline and could outweigh them. Densification of shrubs just above treeline inhibited tree establishment, and slowed upward movement of treelines on a time scale of decades. Interspecific interactions are major processes controlling treeline dynamics that may account for the absence of an upward shift at some TP treelines despite continued climatic warming.alpine treeline | treeline dynamics | climate change | interspecific competition | Tibetan Plateau T he boundary of vegetation formed by alpine treelines is expected to be sensitive to effects of climatic warming on subalpine and alpine ecosystems (1-3). Despite complex mechanisms controlling treeline ecotones (4), the mean root-zone and air temperature is thought to be the primary constraint on tree growth at the high elevations reached by particular tree species (3). As the temperature warms, therefore, treelines are expected to increase in elevation ("shift upward") (e.g., refs. 5-7).In a global meta-analysis, however, Harsch et al. (8) found that treelines shifted upward during the last century at only 52% of 166 locations examined; the majority of treelines upward shifts was attributed to improved winter conditions. Elsewhere, changes in treeline ("treeline displacement") were spatially heterogeneous and slow despite accelerating warming (9, 10). In general, treelines are not always keeping pace with climatic warming on multidecadal time scales, suggesting that upward migration and adjustment of alpine trees to warmer climate conditions may take from several decades to centuries (11), given biotic and climatic factors (e.g., drought, changes in frost damage and insect and pathogen attacks, soil nutrients, or water availability limitations). However, little is known about processes that control upward displacement of treelines in response to long-term warming, and whether alpine tree lines will respond quickly or not to climate warming occurring since the mid-1800s and accelerating today.Treeline displacement results from changes in tree recruitment, growth, and mortality (11, 12). These demographic processes are controlled by different drivers and involve biotic and climatic responses and limitations (4,(13)(14)(15)(16). In addition to physiological responses to ...

The availability of cysteine is thought to be the rate limiting factor for synthesis of the tripeptide glutathione (GSH), based on studies in rodents. GSH status is compromised in various disease states and by certain medications leading to increased morbidity and poor survival. To determine the possible importance of dietary cyst(e)ine availability for whole blood glutathione synthesis in humans, we developed a convenient mass spectrometric method for measurement of the isotopic enrichment of intact GSH and then applied it in a controlled metabolic study. Seven healthy male subjects received during two separate 10-day periods an L-amino acid based diet supplying an adequate amino acid intake or a sulfur amino acid (SAA) (methionine and cysteine) free mixture (SAA-free). On day 10, L-[1-13 C]cysteine was given as a primed, constant i.v. infusion (3mol⅐kg ؊1 ⅐h ؊1 ) for 6 h, and incorporation of label into whole blood GSH determined by GC͞MS selected ion monitoring. The fractional synthesis rate (mean ؎ SD; day -1 ) of whole blood GSH was 0.65 ؎ 0.13 for the adequate diet and 0.49 ؎ 0.13 for the SAA-free diet (P < 0.01). Whole blood GSH was 1,142 ؎ 243 and 1,216 ؎ 162 M for the adequate and SAA-free periods (P > 0.05), and the absolute rate of GSH synthesis was 747 ؎ 216 and 579 ؎ 135 mol⅐liter ؊1 ⅐day ؊1 , respectively (P < 0.05). Thus, a restricted dietary supply of SAA slows the rate of whole blood GSH synthesis and diminishes turnover, with maintenance of the GSH concentration in healthy subjects.