Yisheng Injection Decreases the Expression of H60 and RAE-1 Genes in Ischemic Mice Liver

Role of stress-induced NKG2D ligands in liver diseases

Cell death by apoptosis is a prominent feature in a variety of liver diseases. It is likely that apoptosis is the initial cellular response to hepatocyte and biliary injury, which then leads to the initiation of cellular and cytokine cascades culminating in hepatocyte death with subsequent fibrosis and cirrhosis. This sequence of events is of paramount clinical importance. Recently, soluble forms of the major histocompatibility complex class I-related chains A and closely related B (MIC A and B) were reported to be increased in patients with a variety of liver diseases. MIC A and B are cell surface glycoproteins that function as indicators for cellular stress and thus activate circulating cytotoxic natural killer (NK) cells. The interaction between MIC A and B with their cognate receptor natural killer group 2 member D (NKG2D) culminates in enhanced liver cell death, which is mediated in part by apoptotic mechanisms. The present overview focuses on the role of the stress-induced NKG2D ligands MIC A and B in diverse liver diseases. Critical insights into these complex relations may help to promote rationally based therapies in liver diseases. Importantly, we hope that this overview will help to stimulate further studies into mechanisms by which stress ligands mediate cell death and its sequale.

Coronary artery disease from isolated non-H2-determined incompatibilities in transplanted mouse hearts

BACKGROUND

Most studies of vascular disease in transplanted organs have used combinations involving disparities determined by genes of the major histocompatibility complex (MHC). This report describes examples of coronary vascular disease occurring in transplanted mouse hearts involving isolated, non-H2-determined incompatibilities.

METHODS

Mice, incompatible in respect of HY, H4, or H60, were selected. For H60, the incompatibility depended on breeding congenic pairs or the introduction of H60 by transgenic methods because the latter method results in more widespread expression. Transplant survival was determined, and the appearance and prevalence of coronary artery vasculopathy (CAV) was established by appropriate histologic methods.

RESULTS

Advanced changes of CAV were found at 56 days in transplants involving incompatibilities confined to HY or H4. In both combinations, skin grafts were also rejected. H60 incompatibility does not result in skin graft rejection and only a minority of heart transplants shows evidence of CAV. If heart transplants are preceded by skin grafts bearing both H60 and HY incompatibilities to promote "help" in generating immunity, H60 incompatible hearts develop advanced CAV. Heart transplants in all non-MHC categories ostensibly survive in excellent condition throughout this period despite their CAV.

CONCLUSIONS

CAV can develop as a consequence of non-MHC incompatibilities alone and even when antigens are sparsely expressed on cardiac tissue. Presensitization leads to much more severe vascular disease. Human leukocyte antigen compatible kidney transplants may also develop vascular disease and patients manifesting reactivity to MHC antigens should also be more prone to develop vascular disease because of undetectable non-MHC incompatibilities.

Stromal-derived factor-1 up-regulated the expression of MIC on mouse keratinocyte stem cells

Although previous studies have demonstrated that stromal-derived factor-1 (SDF-1) played a key role in chronic graft dysfunction (CGD), the precise mechanisms underlying this process are not clear. In this study, SDF-1 was injected into keratinocyte stem cells (KSCs) which were isolated and purified from neonatal C57BL/6 (H-2b) mice. Adenylyl cyclase (AC) activity of KSCs was measured and expressions of the human major histocompatibility complex (MHC) class I chain-related antigens A and B (MICA, MICB) detected by immunofluorescence. Cultured KSCs were negative for IA/IE MHC class II molecules by immunofluorescence, indicating the absence of any contamination with Langerhans cells and certifying the purity of KSCs. Over a 7-day culture period, SDF-1 up-regulated AC activity to 2.783 +/- 0.799, which was higher than that of the control group (1.290 +/- 0.476; P < .01). Immunostaining showed that KSCs expressed increased amounts of MICA protein (0.790 +/- 0.134 versus 0.200 +/- 0.022; P < .01) and MICB protein (0.610 +/- 0.832 versus 0.230 +/- 0.016; P < .01). Mixed lymphocyte reaction assays showed that KSCs cultured with SDF-1 injection for 7 days stimulated allogeneic T-cell proliferation. The data indicated that SDF-1 may accelerate the ultimate rejection of allogeneic keratinocytes by enhancing MIC through the AC signal pathway.