Gap Junctions Are Involved in the Rescue of CFTR-Dependent Chloride Efflux by Amniotic Mesenchymal Stem Cells in Coculture with Cystic Fibrosis CFBE41o-Cells

We previously found that human amniotic mesenchymal stem cells (hAMSCs) in coculture with CF immortalised airway epithelial cells (CFBE41o-line, CFBE) on Transwell\uae filters acquired an epithelial phenotype and led to the expression of a mature and functional CFTR protein. In order to explore the role of gap junction-(GJ-) mediated intercellular communication (GJIC) in this rescue, cocultures (hAMSC: CFBE, 1: 5 ratio) were studied for the formation of GJIC, before and after silencing connexin 43 (Cx43), a major component of GJs. Functional GJs in cocultures were inhibited when the expression of the Cx43 protein was downregulated. Transfection of cocultures with siRNA against Cx43 resulted in the absence of specific CFTR signal on the apical membrane and reduction in the mature form of CFTR (band C), and in parallel, the CFTR-dependent chloride channel activity was significantly decreased. Cx43 downregulation determined also a decrease in transepithelial resistance and an increase in paracellular permeability as compared with control cocultures, implying that GJIC may regulate CFTR expression and function that in turn modulate airway epithelium tightness. These results indicate that GJIC is involved in the correction of CFTR chloride channel activity upon the acquisition of an epithelial phenotype by hAMSCs in coculture with CF cells

Las moscas de la fruta (Diptera: Tephritidae) en el Uruguay.

La presente publicación se compone de dos partes, una con los antecedentes internacionales y nacionales sobre los aspectos básicos más relevantes de estas especies y la otra con los proyectos de investigación ejecutados en los últimos cinco años, con la finalidad poner a disposición de productores y asesores técnicos el conocimiento generado sobre las moscas de la fruta en Uruguay

Mercury modulates interplay between IL-1beta, TNF-alpha, and gap junctional intercellular communication in keratinocytes: mitigation by lycopene

Gap junctional intercellular communication (GJIC) is used to control cell proliferation. It is not surprising then that a lack of GJIC (i.e., during loss of contact inhibition among adjacent cells) is associated with cancer promotion/progression. There also seems to be a link between ineffective GJIC and increases in inflammatory events. Interestingly, many cytokines released during an inflammatory response also have critical roles in cancer cell survival. Specifically, TNFα and IL-1β are important for initiating/augmenting CD8+- and NK-cell mediated killing; however, in what appears counterintuitive, each—at times—can act to protect cancer cells against apoptosis, a major mechanism for cell killing from within. It is thus plausible to assume that certain toxicants might act as cancer promoters in manners distinct from/augmentive of direct effects on DNA, i.e., by concurrently altering GJIC and cytokine formation in host or microenvironment of a cancer cell. Our research has evaluated effects of many toxicants upon keratinocytes; in particular, we have examined effects of mercury on GJIC and on TNFα and IL-1β levels in (and secretion by) these cells. In the studies here, a tomato preparation (i.e., an oleoresin) bearing the antioxidant carotenoid lycopene was examined for its effects on GJIC and cytokine formation by keratinocytes in general, and its potential ability to mitigate/ reverse the toxic effects of mercury in the cells in particular. It was shown that a 4-hr treatment with the oleoresin (containing 56, 6 nM lycopene) re-established GJIC among—and increased the formation of IL-1β and TNFα that had been significantly reduced within—keratinocytes that had been pre-treated for 24 hr with 10 nM HgCl2. These results show that effects of mercury likely depend on some level of oxidative stress and that its potential effects on keratinocyte GJIC and cytokine concentrations could, in an exposed host, be mitigated/reversed by increased dietary intake of carotenoids like lycopene

Role of tumour necrosis factor alpha and interleukin 1 beta in promoter effect induced by mercury in human keratinocytes

In the progress of a carcinogenetic process, the promoter effect was seen as the final event ab le to determine uncontrolled proliferation. The promoter effect begins with an inhibition of gap junctional intercellular communication. Previously we observed an inhibitory effect of Mercury (HgC12) on Gap Junction Intercellular Communication of Human Keratinocytes in culture. Here we evaluate the effect of Mercury on gap junctional intercellular communication, on cytokines intracellular concentrations and on cytokines secretion of Human Keratinocytes. In particular, we report a reduction of the intracellular concentrations and secretions of Tumour Necrosis alpha and Interleukin 1 beta. It is known that the inhibitory effect on Gap Junctional Intercellular Communication is correlated with a promoter effect induced by carcinogens. In this paper we discuss the relationship between the inhibition of gap junctional intercellular communication and cytokine production, and whether these effects are related in a xenobiotic carcinogenesis processo Our considerations could be seen as too adventurous, but they may set the stage for an open discussion of our results according to the literature. An intriguing relationship appears to develop when comparing the effects of proinflammatory mediators on GJle. Although highly speculative, a review ofthe current literature would suggest that the GJIC inhibition induced by mercury might be the beginning of the promoter effect, but the role induced by cytokines on initiated cells to stimulate its proliferation remains to be determined. We think that the reduction ofTNF-a, and in part IL-IB, induced by mercury might favour the cancer. We hypothesise that the reduction of cytokines and inhibition of the gap junction intercellular communication are correlated and they may play a role in the xenobiotic carcinogenesis process