Expression and vitamin D-mediated regulation of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in healthy skin and in diabetic foot ulcers.

Diabetic foot ulcers (DFUs) are chronic wounds with high matrix metalloproteinase (MMP) activity, and are a frequent complication on diabetics. This work studied the expression of selected MMP and tissue inhibitor of metalloproteinases (TIMP) gene family members in DFU and normal skin biopsies, and in vitamin D-treated keratinocytes cultured from those biopsies. We report for the first time the expression of some of these genes in healthy skin. Our results suggest that vitamin D may modulate the expression of some MMP gene family members in keratinocytes. Gene expression in DFU and in non-diabetic healthy skin (control) biopsies was evaluated by RT-qPCR for MMP-1, MMP-3, MMP-8, MMP-9, MMP-10, MMP-19, TIMP-1 and TIMP-2, and also by immunohistochemistry for MMP-1 and MMP-9. Primary keratinocytes cultured from DFU and healthy skin biopsies were used for gene expression analyses of selected MMPs and TIMPs by RT-qPCR, both in the presence and absence of calcitriol. The expression of MMP-1, MMP-8, MMP-9, MMP-10, and TIMP-2 in healthy skin is reported here for the first time. DFUs showed increased MMP-1, MMP-9 and TIMP-1 expression, compared to healthy skin. Calcitriol down-regulated MMP-1 and MMP-10 expression in DFU-derived keratinocytes but not in those derived from healthy skin. Our data demonstrate the expression of certain MMPs that had not been previously described in healthy skin, and further support previous reports of MMP and TIMP up-regulation in DFUs. Our results point to calcitriol as a potential modulator for the expression of certain MMP members in DFUs.

Update in bioinformatics. Toward a digital database of plant cell signalling networks: advantages, limitations and predictive aspects of the digital model.

The process of signal integration, which contributes to the regulation of multiple cellular activities, can be described in a digital language by a set of connected digital operations. In this article we delineate the basic concepts of cell signalling in the context of a logical description of information processing. Newly described instances of signal integration in plants are given as examples. The different advantages, limitations and predictive aspects of the digital modeling of signal transduction networks, as well as the minimal architecture of a computer database for plant signalling networks are discussed.