Macrophages allocate before apoptosis initiation and produce reactive oxygen species during interdigital phagocytosis.

During programmed cell death (PCD), it is commonly accepted that macrophages are recruited by apoptotic cells to complete cell degradation. Interdigital cell death, a classical model of PCD, contributes to digit individualization in limbs of mammals and other vertebrates. Here, we show that macrophages are present in interdigits before significant cell death occurs and remain after apoptosis inhibition. The typical interdigital phagocytic activity was not observed after a partial depletion of macrophages and was markedly reduced by engulfment/phagosome maturation inhibition, as detected by its association with high lysosomal activity. ß-galactosidase activity in this region was also coupled with phagocytosis, against its relationship with cellular senescence. Interdigital phagocytosis correlated with high levels of reactive oxygen species (ROS), common in embryo regions carrying abundant cell death, suggesting that macrophages are the major source of ROS. ROS generation was dependent on NADPH oxidases and blood vessel integrity, but not directly associated with lysosomal activity. Therefore, macrophages prepattern regions where abundant cell death is going to occur, and high lysosomal activity and the generation of ROS by an oxidative burst-like phenomenon are activities of phagocytosis.

The loss of antioxidant activities impairs intestinal epithelium homeostasis by altering lipid metabolism.

Reactive oxygens species (ROS) are common byproducts of metabolic reactions and could be at the origin of many diseases of the elderly. Here we investigated the role of ROS in the renewal of the intestinal epithelium in mice lacking catalase (CAT) and/or nicotinamide nucleotide transhydrogenase (NNT) activities. Cat-/- mice have delayed intestinal epithelium renewal and were prone to develop necrotizing enterocolitis upon starvation. Interestingly, crypts lacking CAT showed fewer intestinal stem cells (ISC) and lower stem cell activity than wild-type. In contrast, crypts lacking NNT showed a similar number of ISCs as wild-type but increased stem cell activity, which was also impaired by the loss of CAT. No alteration in the number of Paneth cells (PCs) was observed in crypts of either Cat-/- or Nnt-/- mice, but they showed an evident decline in the amount of lysozyme. Cat deficiency caused fat accumulation in crypts, and a fall in the remarkable high amount of adipose triglyceride lipase (ATGL) in PCs. Notably, the low levels of ATGL in the intestine of Cat -/- mice increased after a treatment with the antioxidant N-acetyl-L-cysteine. Supporting a role of ATGL in the regulation of ISC activity, its inhibition halt intestinal organoid development. These data suggest that the reduction in the renewal capacity of intestine originates from fatty acid metabolic alterations caused by peroxisomal ROS.

In vivo Antitumor Effect of an HPV-specific Promoter driving IL-12 Expression in an HPV 16-positive Murine Model of Cervical Cancer.

Human papillomavirus (HPV) is a DNA virus that infects epithelial cells and has been implicated in the development of cervical cancer. Few therapeutic strategies have been designed for the treatment of cervical intraepithelial neoplasia, a precursor of cervical cancer. In these early stages, the HPV E2 protein is the most important viral factor involved in viral gene expression and plays crucial roles during the vegetative viral cycle in epithelial cells. Papillomavirus E2 binds specifically to palindromic ACCN6GGT sequences, referred to as the E2 binding sites (E2BS), which are concentrated within the viral long control region, and which are responsible for regulation of the HPV protein's expression. Here, we consider E2BS as a candidate sequence to induce the expression of antiviral therapeutic genes selectively in HPV-infected cells expressing the E2 protein. This study focuses on the use of an HPV-specific promoter comprised of four E2BS to drive the expression of IL-12, leading to an antitumor effect in an HPV-positive murine tumor model. The therapeutic strategy was implemented via viral gene therapy using adenoviral vectors with recombinant E2 and IL-12 genes and E2BS-IL-12. We demonstrate that the HPV-specific promoter E2BS is functional in vitro and in vivo through transactivation of HPV E2 transcription factor.