Phosphatidylserine (PS) exposure on the external leaflet of the plasma membrane is widely observed during apoptosis and forms the basis for the annexin V binding assay to detect apoptotic cell death. Current efforts to explain PS exposure focus on two potential mechanisms, activation of a phospholipid scramblase or calcium-mediated trafficking of lysosomes to the cell surface. Here, we provide evidence that apoptotic PS exposure instead reflects bidirectional trafficking of membrane between the cell surface and cytoplasm. Using a series of cell lines, some of which expose large amounts of PS during apoptosis and some of which do not, we demonstrate that accumulation of plasma membrane-derived cytoplasmic vesicles in a dynamin-, clathrin-and Cdc42-independent manner is a previously undescribed but widely occurring feature of apoptosis. The apoptotic exposure of PS occurs when these vesicles traffic back to cell surface in a calcium-dependent process that is deficient in a substantial fraction of human cancer cell lines. These observations provide a new model for PS externalization during apoptosis and simultaneously identify an altered step that accounts for the paucity of apoptotic PS exposure in many cell lines. Cell Death and Differentiation (2013) 20, 64-76; doi:10.1038/cdd.2012; published online 3 August 2012A common feature of apoptosis from Caenorhabditis elegans to man is the transfer of phosphatidylserine (PS) and phosphatidylethanolamine, which ordinarily reside on the cytoplasmic surface of the membranes, to the cell surface.

Despite recent advances in the chemotherapy of chronic hepatitis B (CHB), an effective viral suppression after cessation of therapy has not yet been achieved. To investigate whether hepatitis B virus (HBV)-specific T-cell responses are inducible and can contribute to the viral suppression after cessation of the therapy, we conducted a proof-of-concept study with a DNA vaccine comprising of most HBV genes plus genetically engineered interleukin-12 DNA (IL-12N222L) in 12 CHB carriers being treated with lamivudine (LAM). When the ex vivo and/or cultured IFN-g enzyme-linked immunospot (ELISPOT) assay was performed, the detectable HBV-specific IFN-g secreting T-cell responses were observed at the end of treatment and during a follow-up. These type 1T-cell responses, particularly CD4 + memory T-cell responses could be maintained for at least 40 weeks after the therapy and correlated with virological responses, but not with alanine aminotransferase elevation. Moreover, DNA vaccination under LAM treatment appeared to be well-tolerated and showed 50% of virological response rate in CHB carriers. Thus, a combination therapy of the DNA vaccine with chemotherapy may be one of new immunotherapeutic methods for the cure of CHB. Gene Therapy ( Patients with chronic HBV infection who showed remission also develop vigorous CTL and strong type 1T helper (Th1) immune responses that are comparable to those in patients who have a selflimited disease. 4 In contrast, the CTL and Th1 responses are undetectable or relatively weak in patients with chronic HBV infection. 3,5 Lamivudine (LAM) and adefovir dipivoxil as nucleoside analogues can suppress HBV replication effectively during treatment period, 6,7 but their use is limited by the high risk of viral relapse upon discontinuation even after long-term treatment.2 A restoration of HBV-specific CD4 + and CD8 + T-cell responses by LAM monotherapy was previously observed, but these T-cell responses were not only transient during treatment, but were also undetectable or very weak at the end of 1-year treatment. 8,9 It was recently reported that the inverse correlation between the number of antigen-specific interferon (IFN)-g producing CD4 + T cells and serum HBV DNA was observed during the treatment of LAM with recombinant interleukin-12 (IL-12) protein, but not detectable after the treatment. 10Therefore, further studies are needed to elucidate the relationship between T-cell responses and the suppression of viral relapse after stopping the therapy.DNA vaccine has the advantage of inducing both humoral and cellular immune responses, especially Th1 and CTL responses. HBV DNA vaccine was shown to induce strong T-cell responses, leading to the suppression of viral replication in HBV transgenic mice.11 In contrast, DNA immunization induced very weak T-cell

Our results suggest that the presence of the I allele may confer susceptibility to development of psoriasis among ethnically Chinese Taiwanese individuals.

The cellular prion protein (PrP) is associated with metastasis, tumor progression and recurrence; however, the precise mechanisms underlying its action is not well understood. Our study found that PrP degradation decreased tumor progression in colorectal cancer (CRC). In a CRC cell line and human CRC tissue exposed to hypoxia, induced heat-shock 70-kDa protein-1-like (HSPA1L) expression stabilized hypoxia-inducible factor-1α (HIF-1α) protein and promoted PrP accumulation and tumorigenicity in vivo. PrP was degraded via the proteasome pathway mediated by the ubiquitin-protein E3 ligase glycoprotein 78 (GP78), which interacts directly with PrP. However, hypoxia-induced HSPA1L interacted with GP78 and inhibited its functions. HSPA1L knockdown facilitated the interaction of GP78 and PrP, thereby increasing PrP ubiquitination. Thus, GP78 was identified as the ubiquitinase for PrP, thereby revealing an essential mechanism that controls PrP levels in CRC. Our results suggest that the HSPA1L/HIF-1α/GP78 axis has a crucial role in PrP accumulation during tumor progression.