Pancreatic Progenitor Commitment Is Marked by an Increase in Ink4a/Arf Expression

The identification of the molecular mechanisms controlling early cell fate decisions in mammals is of paramount importance as the ability to determine specific lineage differentiation represents a significant opportunity for new therapies. Pancreatic Progenitor Cells (PPCs) constitute a regenerative reserve essential for the maintenance and regeneration of the pancreas. Besides, PPCs represent an excellent model for understanding pathological pancreatic cellular remodeling. Given the lack of valid markers of early endoderm, the identification of new ones is of fundamental importance. Both products of the Ink4a/Arf locus, in addition to being critical cell-cycle regulators, appear to be involved in several disease pathologies. Moreover, the locus' expression is epigenetically regulated in ES reprogramming processes, thus constituting the ideal candidates to modulate PPCs homeostasis. In this study, starting from mouse embryonic stem cells (mESCs), we analyzed the early stages of pancreatic commitment. By inducing mESCs commitment to the pancreatic lineage, we observed that both products of the Cdkn2a locus, Ink4a and Arf, mark a naïve pancreatic cellular state that resembled PPC-like specification. Treatment with epi-drugs suggests a role for chromatin remodeling in the CDKN2a (Cycline Dependent Kinase Inhibitor 2A) locus regulation in line with previous observations in other cellular systems. Our data considerably improve the comprehension of pancreatic cellular ontogeny, which could be critical for implementing pluripotent stem cells programming and reprogramming toward pancreatic lineage commitment.

Curcumin dietary supplementation ameliorates disease phenotype in an animal model of Huntington's disease

Huntington's disease (HD) has traditionally been described as a disorder purely of the brain; however, evidence indicates that peripheral abnormalities are also commonly seen. Among others, severe unintended body weight loss represents a prevalent and often debilitating feature of HD pathology, with no therapies available. It correlates with disease progression and significantly affects the quality of life of HD patients. Curcumin, a naturally occurring polyphenol with multiple therapeutic properties, has been validated to exert important beneficial effects under health conditions as well as in different pathological settings, including neurodegenerative and gastrointestinal (GI) disorders. Here, we investigated the potential therapeutic action that curcumin-supplemented diet may exert on central and peripheral dysfunctions in R6/2 mice, a well-characterized HD animal model which recapitulates some features of human pathology. Maintenance of normal motor function, protection from neuropathology and from GI dysfunction and preservation of GI emptying and conserved intestinal contractility, proved the beneficial role of life-long dietary curcumin in HD and corroborated the potential of the compound to be exploited to alleviate very debilitating symptoms associated with the disease.

Colloidal Silver Induces Cytoskeleton Reorganization and E-Cadherin Recruitment at Cell-Cell Contacts in HaCaT Cells

Up until the first half of the 20th century, silver found significant employment in medical applications, particularly in the healing of open wounds, thanks to its antibacterial and antifungal properties. Wound repair is a complex and dynamic biological process regulated by several pathways that cooperate to restore tissue integrity and homeostasis. To facilitate healing, injuries need to be promptly treated. Recently, the interest in alternatives to antibiotics has been raised given the widespread phenomenon of antibiotic resistance. Among these alternatives, the use of silver appears to be a valid option, so a resurgence in its use has been recently observed. In particular, in contrast to ionic silver, colloidal silver, a suspension of metallic silver particles, shows antibacterial activity displaying less or no toxicity. However, the human health risks associated with exposure to silver nanoparticles (NP) appear to be conflicted, and some studies have suggested that it could be toxic in different cellular contexts. These potentially harmful effects of silver NP depend on various parameters including NP size, which commonly range from 1 to 100 nm. In this study, we analyzed the effect of a colloidal silver preparation composed of very small and homogeneous nanoparticles of 0.62 nm size, smaller than those previously tested. We found no adverse effect on the cell proliferation of HaCaT cells, even at high NP concentration. Time-lapse microscopy and indirect immunofluorescence experiments demonstrated that this preparation of colloidal silver strongly increased cell migration, re-modeled the cytoskeleton, and caused recruitment of E-cadherin at cell-cell junctions of human cultured keratinocytes.

P-glycoprotein expression in circulating blood leukocytes of patients with steroid-resistant asthma

P-Glycoprotein is a transmembrane efflux pump for different lipophilic drugs including glucocorticosteroids. Thus, upregulation of P-glycoprotein may provide a mechanism for reduced glucocorticosteroid responses as they occur in steroid-resistant asthma. To address this issue, we have examined freshly isolated peripheral blood mononuclear cells and granulocytes with regards to P-glycoprotein functional and surface expression. Using two-color immuno fluorescence techniques, we demonstrated a direct correlation between the efflux of the fluorescent dye Rh 123 and P-glycoprotein surface expression in lymphocytes, NK (natural killer) cells, monocytes and granulocytes. P-Glycoprotein levels varied widely between different leucocytes, with NK cells and CD8+ T cells having high, and granulocytes having no detectable levels. There was no evidence for upregulation of P-glycoprotein expression in any cell type from patients with steroid-resistant asthma compared to patients with steroid-sensitive or mild asthma. These results suggest that increased P-glycoprotein expression can be excluded as a mechanism for steroid resistance. Interestingly, a down regulation of P-glycoprotein expression in B cells was associated with systemic glucocorticosteroid treatment in vivo and in vitro. Whether this phenomenon may account for reduced immunoglobulin levels associated with oral glucocortico-steroid therapy remains to be determined.

[Functional IgG subclass determinations in patients with suspected humoral immune defects using the LIBA technique]

In patients with recurrent infections, "intrinsic" asthma and lymphoma the specific binding capacity of IgG subclass 2 against pneumococcus was determined by line-immuno-binding-assay (LIBA). The results show that LIBA represents a simple and specific test system suitable as diagnostic parameter in patients with a suspected humoral defect.

Differential cytokine profiles in peripheral blood lymphocyte supernatants and skin biopsies from patients with different forms of atopic dermatitis, psoriasis and normal individuals

There is increasing evidence that the activation of a selected T helper cell population producing a Th2-related cytokine pattern with IL-4 and IL-5 but not IL-2 and interferon-gamma (IFN-gamma) may be involved in the pathogenesis of IgE-mediated atopic diseases and in particular of atopic dermatitis (AD). However, the existence of a 'nonatopic' (intrinsic) form of AD (NAD) with normal serum IgE levels, negative RAST tests, negative immediate type skin reactions towards environmental allergens and a negative patients and family history for IgE-mediated allergies raised the question whether this form may be explained by a different T cell activation and cytokine pattern. In the present study we compared the distribution of peripheral blood leukocyte and lymphocyte subpopulations, their activation state and cytokine production in peripheral blood lymphocyte supernatants and skin biopsies of patients with AD (n = 19), NAD (n = 14), psoriasis (n = 6) and normal individuals (n = 13). A characteristic eosinophilia was present in AD and NAD but not in psoriasis and normal controls. The three patient groups showed significantly increased numbers of activated CD4+ and CD8+ cells as measured by IL-2R and HLA-DR expression. Determination of spontaneously released IL-2, IL-4, IL-5 and IFN-gamma from peripheral blood lymphocytes demonstrated a Th2-related cytokine pattern with elevated levels for IL-4 and IL-5 in AD patients only. Increasingly enough, patients with NAD displayed high IL-5 but low IL-4 levels.(ABSTRACT TRUNCATED AT 250 WORDS)