Structural tuning of coordination polymers with photoluminescent properties via temperature control

Using a two-solvent interdiffusion technique, the ligand tpatpy that possesses aggregation-induced emission (AIE) properties was coordinated to Cd2+ to construct two coordination polymers under conditions that differed only by reaction temperatures of 30 °C and 0 °C for 1 and 2, respectively. Single-crystal X-ray diffraction studies revealed the key structural differences were that the metal centers in 1 were five-coordinate, versus four-coordinate in 2. Thus, this system could be tuned by controlling the temperature during synthesis. UV-visible spectroscopy (UV-Vis), infrared spectroscopy (IR), powder X-ray diffraction (PXRD), thermogravimetry (TG), and the fluorescence of 1 and 2 are discussed to provide a comprehensive discussion of physical and electronic properties.</p

Both Notch signaling and proteasome pathway contributes to the osteogenesis of hUC-MSCs.

<p>The semi-quantitative RT-PCR shows that the treatment with 2.5 μM GSI-I significantly reduces RGC32 transcription at day 1 and day 3 after osteogenic induction (A). However, whereas 5 nM Bortezomib alone reduces RGC32 transcription at day 3, not day 1, of osteogenic induction, and siNotch transfection alone slightly reduces RGC32 transcription at both day 1 and day 3, the combination of both siNotch1 transfection and Bortezomib treatment significantly reduces the transcription at both day 1 and day 3 after osteogenic induction (B).</p

The Notch1 signaling is involved in immunomodulation of hUC-MSCs through promoting IDO1 transcription.

<p>A. Luciferase assay shows that, after transfection with pIDO1-Luc, the IDO1 promoter can be significantly activated in hUC-MSCs by 2 ng/mL IFN-γ. However, such activity can be significantly inhibited by GSI-I in a dose-dependent manner. B. Luciferase assay shows that siNotch1 transfection reduces over 50% of the IDO1 promoter activity. The * indicates statistical significance with <i>p</i><0.05. C. Flow cytometry assay shows that treatment with 0.1 mM 1-L-MT during co-culturing of hUC-MSC and PBMCs can significantly reduce the effect of hUC-MSCs on inhibition of Th1 lymphocyte proliferation. The * indicates statistical significance with <i>p</i><<i>0.05</i>D. D. The flow cytometry blot data are corresponding to the results of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0118168#pone.0118168.g009" target="_blank">Fig. 9C</a>. The Th1 lymphocytes circled in the plot are the CD8^-/IFN-γ⁺ lymphocytes.</p

Both Notch signaling and proteasome pathway are involved in regulating CD105 expression in hUC-MSCs.

<p>Flow cytometry assay shows that 0.25–1 μM GSI-I do not induce changes in expression of CD73, CD90 and CD105 (A), but 5–10nM Bortezomib significantly inhibits the expression of CD105, but not CD73 and CD90 (B); Moreover, while the siNotch1 transfection alone has no effect on expression of surface markers, it further increases the inhibitory effect of 10 nM Bortezomib on CD105, slightly on CD90, but not on CD73 (C). The * indicates the statistical significance with <i>p</i><0.05.</p

The GSI-I treatment reduces expression of positive MSC surface markers.

<p>Representative histogram from a flow cytometry assay shows that, while over 95% untreated hUC-MSCs are positive for CD73, CD90 and CD105 (A), the treatment significantly reduces the positivity for each surface marker with the most significance seen for CD105 reduction. The * indicates the statistical significance with <i>p</i><0.05 (B).</p

The GSI-I treatment reduces osteogenesis of hUC-MSCs.

<p>A. The treatment inhibits intracellular calcium deposition as detected by Alizarin Red staining at 14 d after osteogenic induction. B. The semi-quantitative RT-PCR shows that the osteogenic induction induces RGC32 gene expression starting at 12 h and reaching to a plateau at day 3 (B-1, B-2). However, the GSI-I treatment with greater than 2.5 μM GSI-I significantly reduces RGC32 transcription at 24 h after treatment (B-3). The cells without osteogenic induction serve as negative control.</p

The GSI-I treatment inhibits hUC-MSC activities in suppressing Th1 lymphocyte proliferation and IDO1 expression.

<p>A. Flow cytometry assay shows that co-culturing of hUC-MSC with PBMC in 1:5 ratio significantly inhibits Th1 lymphocyte proliferation. However, the treatment with 2.5 μM GSI-I significantly inhibits the effect of hUC-MSCs on Th1 proliferation. A-1: bar figure; A-2: original spectrogram of a representative Th1 lymphocyte analysis. Th1 lymphocytes are CD8-/IFN-g+ cells as circled in the spectrogram. B. The GSI-I treatment reduces the IFN-γ-induced IDO1 expression. Both semi-quantitative RT-PCR (B-1) and Western blotting (B-2) show that, while 2ng/mL IFN- γ induces IDO1 expression in hUC-MSCs, greater than 2.5 M GSI-I dramatically reduces the IDO1 expression.</p

The GSI-I treatment inhibits both Notch and ubiquitin-proteasome signaling in hUC-MSCs.

<p>A. Both GSI-I and Bortezomib inhibit ubiquitin-proteasome signaling. The Western blotting following immunoprecipitation shows that the treatment with 1.0–10.0 μM GSI-I or 5–10 nM Bortezomib significantly elevates the level of ubiquitin-conjugated Mcl-1 protein. A-1 is from the data using 2.5 μM-10.0 μM of GSI-I and 2.5–5 nM Bortezomib and A-2 is from the data using 0–2.5 μM of GSI-I and 10 nM of Bortezomib. B. GSI-I, but not Bortezomib, inhibits the Notch signaling. The Western blotting shows that, whereas 0.25–1 μM GSI-I reduce levels of the cleaved form of Notch1 and Hes1 proteins (B-1), 2.5–10 nM Bortezomib however significantly increase Hes1 protein level (B-2).</p

The Notch signaling plays a predominant role in maintaining immunomodulatory activities of hUC-MSCs.

<p>A. Western blotting shows that Bortezomib alone does not affect the IFN-γ-induced IDO1 expression, does not induce apoptosis as no PARP cleavage was induced, but elevates Mcl-1 protein level. B. Western blotting shows that siNotch1 transfection can silence approximately 50% of IDO1 protein expression, but does not induce apoptosis. C. Western blotting shows that treatment with 5 nM Bortezomib does not further enhance the effect of siNotch1 transfection on IDO1 reduction. In addition, Bortezomib and siNotch1 together do not induce apoptosis as no PARP cleavage is observed. D. The flow cytometry assay shows that siNotch1 transfection alone can significantly reduce the inhibitory effect of hUC-MSCs on Th1 lymphocyte proliferation. Bortezomib alone shows no such effect and does not enhance the effect of siNotch1 either. The * indicates statistical significance with <i>p</i><0.05.</p

Proteasome-mediated degradation plays a role in STING reduction.

<p>(A) Time course assessment of STING mRNA expression after MRC-5 cells were transfected with pcDNA3.1 (0.05μg). (B) Western blotting assessment of STING after MRC-5 cells were transfected with pcDNA3.1 (0.05μg) with treatment of Bortezomib (20 nM) or DMSO for 18h. (C)Western blotting assessment of immunoprecipitated STING with anti-ubiquitin antibody.</p