This clinical study aimed to determine whether periodontal disease is associated with expression of developmental endothelial locus-1 (Del-1) and pentraxin-3 (PTX-3), endogenous inhibitors of leukocyte extravasation in humans. Expression of DEL1, PTX3, interleukin-17A (IL17A), and lymphocyte function-associated antigen-1 (LFA1) was determined, using RT-PCR and melting curve analysis, in biopsies of gingival tissues from 95 patients: 42 with moderate periodontitis; 40 with severe periodontitis; and 13 healthy controls. Relative expression of DEL1 and PTX3 was statistically significantly weaker in patients with periodontitis than in the control subjects. On the contrary, both IL17A and LFA1 showed statistically significant stronger expression in patients with periodontitis than in healthy controls. Correlation analysis, performed using Spearman's test, showed that expression of DEL1 was statistically significantly linked to periodontitis (ρ = -0.103) and to age (ρ = -0.134), but not to the gender of the patient, and that expression of PTX3 was significantly correlated with periodontitis (ρ = -0.354). Expression of neutrophil extravasation inhibitors DEL1 and PTX3 show significant, but weak, association with the clinical manifestation of chronic periodontitis.

The transmembrane protein ToxR plays a key role in the virulence expression system of Vibrio cholerae. The activity of ToxR is dependent on its periplasmic sensor domain (ToxRp) and on the inner membrane protein ToxS. Herein, we present the Nuclear Magnetic Resonance NMR solution structure of the sensory ToxRp containing an intramolecular disulfide bond. The presented structural and dynamic experiments with reduced and oxidized ToxRp propose an explanation for the increased proteolytic sensitivity of reduced ToxR. Additionally, for the first time, we could identify the formation of a strong heterodimer complex between the periplasmic domains of ToxR and ToxS in solution. NMR interaction studies reveal that binding of ToxS is not dependent on the redox state of ToxR cysteines, and formed complexes are structurally similar. By monitoring the proteolytic cleavage of ToxRp with NMR, we additionally provide a direct evidence of ToxS protective function. Taken together our results suggest that ToxR activity is regulated by its stability which is, on the one hand, dependent on the redox states of its cysteines, influencing the stability of its fold, and on the other hand, on its interaction with ToxS, which binds independent on the cysteines and acts as a protection against proteases.

Human mesenchymal stem cells (hMSCs) are a promising target for cell-based bone regeneration. However, their application for clinical use is limited because hMSCs lose their ability for cell division and differentiation during longer in vitro cultivation. The osteogenic differentiation is regulated through a complex network of molecular signal transduction pathways where the canonical Wnt pathway plays an important role. Sox2, a known key factor for maintenance of cellular pluripotency in stem cells, is supposed to influence the Wnt pathway in osteoblasts. In this study, we overexpressed Sox2 in immortalized hMSCs by lentiviral gene transfer. Sox2 overexpression significantly reduced the osteogenic and adipogenic differentiation potentials. This effect was abolished by knockdown of Sox2 overexpression. In addition, Oct4 and Nanog, other key transcription factors for pluripotency, are strongly upregulated when Sox2 is overexpressed. Furthermore, Dkk1, a target gene of the Sox2-Oct4 heterodimer and a Wnt antagonist, is downregulated. Sox2 overexpression causes higher expression levels of β-catenin, the central transcription factor of the canonical Wnt pathway. These results suggest that Sox2 keeps hMSCs in an undifferentiated state by influencing the canonical Wnt pathway. Regulated expression of Sox2 may be a promising tool to cultivate hMSCs in sufficient quantities for cell and gene therapy applications.

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