Mesenchymal stem cells are often transplanted into inflammatory environments where they are able to survive and modulate host immune responses through a poorly understood mechanism. In this paper we analyzed the responses of MSC to IL-1β: a representative inflammatory mediator. Microarray analysis of MSC treated with IL-1β revealed that this cytokine activateds a set of genes related to biological processes such as cell survival, cell migration, cell adhesion, chemokine production, induction of angiogenesis and modulation of the immune response. Further more detailed analysis by real-time PCR and functional assays revealed that IL-1β mainly increaseds the production of chemokines such as CCL5, CCL20, CXCL1, CXCL3, CXCL5, CXCL6, CXCL10, CXCL11 and CX3CL1, interleukins IL-6, IL-8, IL23A, IL32, Toll-like receptors TLR2, TLR4, CLDN1, metalloproteins MMP1 and MMP3, growth factors CSF2 and TNF-α, together with adhesion molecules ICAM1 and ICAM4. Functional analysis of MSC proliferation, migration and adhesion to extracellular matrix components revealed that IL-1β did not affect proliferation but also served to induce the secretion of trophic factors and adhesion to ECM components such as collagen and laminin. IL-1β treatment enhanced the ability of MSC to recruit monocytes and granulocytes in vitro. Blockade of NF-κβ transcription factor activation with IκB kinase beta (IKKβ) shRNA impaired MSC migration, adhesion and leucocyte recruitment, induced by IL-1β demonstrating that NF-κB pathway is an important downstream regulator of these responses. These findings are relevant to understanding the biological responses of MSC to inflammatory environments.Electronic supplementary materialThe online version of this article (doi:10.1007/s12015-012-9364-9) contains supplementary material, which is available to authorized users.

SummarymiR-133a and miR-1 are known as muscle-specific microRNAs that are involved in cardiac development and pathophysiology. We have shown that both miR-1 and miR-133a are early and progressively upregulated during in vitro cardiac differentiation of adult cardiac progenitor cells (CPCs), but only miR-133a expression was enhanced under in vitro oxidative stress. miR-1 was demonstrated to favor differentiation of CPCs, whereas miR-133a overexpression protected CPCs against cell death, targeting, among others, the proapoptotic genes Bim and Bmf. miR-133a-CPCs clearly improved cardiac function in a rat myocardial infarction model by reducing fibrosis and hypertrophy and increasing vascularization and cardiomyocyte proliferation. The beneficial effects of miR-133a-CPCs seem to correlate with the upregulated expression of several relevant paracrine factors and the plausible cooperative secretion of miR-133a via exosomal transport. Finally, an in vitro heart muscle model confirmed the antiapoptotic effects of miR-133a-CPCs, favoring the structuration and contractile functionality of the artificial tissue.

The tissue organisation of dermal collagen is gaining importance as a contributing factor both in development and ageing, as well as in skin maturation processes. In this work we aim to study different representative parameters of this structural organisation in 45 human skin samples of assorted ages, by means of image analysis. The variation of these parameters on the basis of age was assessed using several regression models (linear, quadratic and cubic). The area occupied by collagen was significantly reduced as a function of age in the papillary dermis (R 2 = 0.437, P < 0.0001), as well as the thickness of the collagen bundles (R 2 = 0.461, P < 0.0001), following statistical models of cubic and quadratic regression, respectively. The width of the papillary dermis increased in a significant manner over a linear regression model (R 2 = 0.26, P < 0.0001). In the reticular dermis, the cubic regression indicated a significant decline (R 2 = 0.392, P = 0.002) of the area filled with collagen according to the age. Both collagen thickness and bundle orientation parameters fit a quadratic regression over the age in a significant way (R 2 = 0.433 and R 2 = 0.334, respectively, both P < 0.0001). The width of the reticular dermis followed also a significant quadratic distribution according to age (R 2 = 0.193, P = 0.011). These parameters could partially explain the lifelong functional changes taking place in the skin and propose a baseline providing a useful entry point for future investigation.

Background and purpose:The effects of a phosphodiesterase 4 (PDE4) inhibitor, roflumilast, on bleomycin-induced lung injury were explored in 'preventive' and 'therapeutic' protocols and compared with glucocorticoids. Experimental approach: Roflumilast (1 and 5 mg·kg, p.o.) was given to C57Bl/6J mice from day 1 to 14 (preventive) or day 7 to 21 (therapeutic) after intratracheal bleomycin (3.75 U·kg ). Analyses were performed at the end of the treatment periods. Key results: Preventive. Roflumilast reduced bleomycin-induced lung hydroxyproline, lung fibrosis and right ventricular hypertrophy; muscularization of intraacinar pulmonary vessels was also attenuated. The PDE4 inhibitor diminished bleomycininduced transcripts for tumour necrosis factor (TNFa), transforming growth factor (TGFb), connective tissue growth factor, aI(I)collagen, endothelin-1 and the mucin, Muc5ac, in lung, and reduced bronchoalveolar lavage fluid levels of TNFa, interleukin-13, TGFb, Muc5ac, lipid hydroperoxides and inflammatory cell counts. Therapeutic. In mice, roflumilast but not dexamethasone reduced bleomycin-induced lung aI(I)collagen transcripts, fibrosis and right ventricular hypertrophy. Similar results were found in the rat. Conclusions and implications:Roflumilast prevented the development of bleomycin-induced lung injury, and alleviated the lung fibrotic and vascular remodeling response to bleomycin in a therapeutic protocol, the latter being resistant to glucocorticoids.

Mesenchymal stem cells (MSC) are effective in treating myocardial infarction (MI) and previous reports demonstrated that hypoxia improves MSC self-renewal and therapeutics. Considering that hypoxia-inducible factor-1 alpha (HIF-1a) is a master regulator of the adaptative response to hypoxia, we hypothesized that HIF-1a overexpression in MSC could mimic some of the mechanisms triggered by hypoxia and increase their therapeutic potential without hypoxia stimulation. Transduction of MSC with HIF-1a lentivirus vectors (MSC-HIF) resulted in increased cell adhesion and migration, and activation of target genes coding for paracrine factors. When MSC-HIF were intramyocardially injected in infarcted nude rats, significant improvement was found (after treatment of infarcted rats with MSC-HIF) in terms of cardiac function, angiogenesis, cardiomyocyte proliferation, and reduction of fibrotic tissue with no induction of cardiac hypertrophy. This finding provides evidences for a crucial role of HIF-1a on MSC biology and suggests the stabilization of HIF-1a as a novel strategy for cellular therapies.

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Mesenchymal stem cells might be more effective than CD34(+) cells for the healing of the infarct. This study contributes to elucidate the mechanisms by which these cell types operate in the course of MI treatment.