Mitochondria, which are the cellular energy plants, also act as the integration center of cellular signaling pathways. Apoptosis is a well-known pathway in which mitochondria are involved. Protein kinase Cepsilon has been classified as a novel type of protein kinase C and is involved in many cellula

Mitochondria, which are the cellular energy plants, also act as the integration center of cellular signaling pathways. Apoptosis is a well-known pathway in which mitochondria are involved. Protein kinase Cepsilon has been classified as a novel type of protein kinase C and is involved in many cellular events regulating mitochondrial function. Much evidence has accumulated regarding the relationships between mitochondria-mediated apoptosis and protein kinase Cepsilon. Therefore, by focusing on these relationships, in particular the anti-apoptotic effects of protein kinase Cepsilon on mitochondrial function, we highlight the importance and significance of protein kinase Cepsilon in cell survival and death.

ABSTRACT: BACKGROUND: Oral keratinocytes on the mucosal surface are frequently exposed to HIV-1 through contact with infected sexual partners or nursing mothers. To determine the plausibility that oral keratinocytes are primary targets of HIV-1, we tested the hypothesis that HIV-1 infects oral kerat

ABSTRACT: BACKGROUND: Oral keratinocytes on the mucosal surface are frequently exposed to HIV-1 through contact with infected sexual partners or nursing mothers. To determine the plausibility that oral keratinocytes are primary targets of HIV-1, we tested the hypothesis that HIV-1 infects oral keratinocytes in a restricted manner. RESULTS: To study the fate of HIV-1, immortalized oral keratinocytes (OKF6/TERT-2; TERT-2 cells) were characterized for the fate of HIV-specific RNA and DNA. At 6 h post inoculation with X4 or R5-tropic HIV-1, HIV-1gag RNA was detected maximally within TERT-2 cells. Reverse transcriptase activity in TERT-2 cells was confirmed by VSV-G-mediated infection with HIV-NL4-3Deltaenv-EGFP. AZT inhibited EGFP expression in a dose-dependent manner, suggesting that viral replication can be supported if receptors are bypassed. Within 3 h post inoculation, integrated HIV-1 DNA was detected in TERT-2 cell nuclei and persisted after subculture. Multiply spliced and unspliced HIV-1 mRNAs were not detectable up to 72 h post inoculation, suggesting that HIV replication may abort and that infection is non-productive. Within 48 h post inoculation, however, virus harbored by CD4 negative TERT-2 cells trans infected co-cultured peripheral blood mononuclear cells (PBMCs) or MOLT4 cells (CD4 CCR5 ) by direct cell-to-cell transfer or by releasing low levels of infectious virions. Primary tonsil epithelial cells also trans infected HIV-1 to permissive cells in a donor-specific manner. CONCLUSIONS: Oral keratinocytes appear, therefore, to support stable non-replicative integration, while harboring and transmitting infectious X4- or R5-tropic HIV-1 to permissive cells for up to 48 h.

Different cardiac stem/progenitor cells have been recently identified in the post-natal heart. We describe here the identification, clonal expansion and characterization of self-renewing progenitors that differ from those previously described for high spontaneous cardiac differentiation. Unique coex

Different cardiac stem/progenitor cells have been recently identified in the post-natal heart. We describe here the identification, clonal expansion and characterization of self-renewing progenitors that differ from those previously described for high spontaneous cardiac differentiation. Unique coexpression of endothelial and pericyte markers identify these cells as cardiac mesoangioblasts and allow prospective isolation and clonal expansion from the juvenile mouse ventricle. Cardiac mesoangioblasts express many cardiac transcription factors and spontaneously differentiate into beating cardiomyocytes that assemble mature sarcomeres and express typical cardiac ion channels. Cells similarly isolated from the atrium do not spontaneously differentiate. When injected into the ventricle after coronary artery ligation, cardiac mesoangioblasts efficiently generate new myocardium in the peripheral area of the necrotic zone, as they do when grafted in the embryonic chick heart. These data identify cardiac mesoangioblasts as committed progenitors, downstream of earlier stem/progenitor cells and suitable for the cell therapy of a subset of juvenile cardiac diseases.Cell Death and Differentiation advance online publication, 23 May 2008; doi:10.1038/cdd.2008.75.