Integrin-linked kinase, a hypoxia-responsive molecule, controls postnatal vasculogenesis by recruitment of endothelial progenitor cells to ischemic tissue

BACKGROUND: Recruitment and adhesion of endothelial progenitor cells (EPCs) to hypoxic endothelial cells (ECs) is essential for vasculogenesis in ischemic tissue; little is known, however, about the key signals or intracellular signaling pathways involved in orchestrating the expression of adhesion molecules by ECs in response to hypoxia and how this is related to the recruitment of EPCs to the ischemic tissue. Here, we report that endogenous integrin-linked kinase (ILK) is a novel molecule that responds to hypoxia in ECs that regulates the expression of stromal cell-derived factor-1 (SDF-1) and intercellular adhesion molecule-1 (ICAM-1) through nuclear factor-kappaB and hypoxia-inducible factor-1alpha and induces recruitment of EPCs to ischemic areas. METHODS AND RESULTS: Under hypoxia, both the endogenous amount and kinase activity of ILK were time-dependently upregulated in ECs, which was associated with increased ICAM-1 and SDF-1. This upregulation of ILK was mediated by stabilization of ILK by heat shock protein 90. ILK overexpression in normoxic ECs resulted in ICAM-1 and SDF-1 upregulation through dual control by nuclear factor-kappaB and hypoxia-inducible factor-1alpha. Blockade of ILK in hypoxic ECs significantly abrogated the expression of both molecules, which led to decreased EPC incorporation into ECs. A hindlimb ischemia model showed that ILK blockade significantly reduced EPC homing to ischemic limb and consequently led to poor neovascularization. Overexpression of ILK in the Matrigel plug significantly improved neovascularization in vivo, whereas the blockade of ILK resulted in the opposite effect. CONCLUSIONS: Endogenous ILK is a novel and physiological upstream responder of numerous intracellular molecules involved in hypoxic stress in ECs and may control the recruitment of EPCs to ischemic tissue

Engineering counter-ion-induced disorder of a highly doped conjugated polymer for high thermoelectric performance

Disorder of doped conjugated polymers, which affects how effectively charge carriers are transported, is an important factor to be controlled to achieve high thermoelectric (TE) performance. However, experimentally controlling the disorder in highly doped polymers is difficult because of the limitations of dopant engineering. Here, by using a counter-ion exchange method, we systematically control the counter-ion-induced disorder in a highly doped state and analyze how the disorder changes the TE transport properties in poly(3,4ethylenedioxythiophene) (PEDOT). Multi-cyano-functionalized counter-ions, which exhibit different Coulombic attraction with PEDOT, change the structural and energetic disorder in PEDOT. These changes in the disorder are evaluated with respect to several qualities of PEDOT: crystalline ordering, density of states (DOS), and polaron behaviors. Decreasing the counter-ion-induced localization of charge carriers in PEDOT increases the planarity of the PEDOT chains and narrows the DOS of PEDOT. In addition, an analysis of the number of unpaired polarons and the Curie susceptibility shows quantitatively how the charge carriers are localized by the counter-ion-induced disorder in PEDOT. These changes result in opposite behaviors of the electrical conductivity and the Seebeck coefficient in PEDOT in response to the extent of disorder and thereby produce a high figure of merit ZT of 0.21 with a remarkable power factor in the PEDOT film with the lowest degree of disorder. Disorder of doped conjugated polymers, which affects how effectively charge carriers are transported, is an important factor to be controlled to achieve high thermoelectric (TE) performance. However, experimentally controlling the disorder in highly doped polymers is difficult because of the limitations of dopant engineering. Here, by using a counter-ion exchange method, we systematically control the counter-ion-induced disorder in a highly doped state and analyze how the disorder changes the TE transport properties in poly(3,4ethylenedioxythiophene) (PEDOT). Multi-cyano-functionalized counter-ions, which exhibit different Coulombic attraction with PEDOT, change the structural and energetic disorder in PEDOT. These changes in the disorder are evaluated with respect to several qualities of PEDOT: crystalline ordering, density of states (DOS), and polaron behaviors. Decreasing the counter-ion-induced localization of charge carriers in PEDOT increases the planarity of the PEDOT chains and narrows the DOS of PEDOT. In addition, an analysis of the number of unpaired polarons and the Curie susceptibility shows quantitatively how the charge carriers are localized by the counter-ion-induced disorder in PEDOT. These changes result in opposite behaviors of the electrical conductivity and the Seebeck coefficient in PEDOT in response to the extent of disorder and thereby produce a high figure of merit ZT of 0.21 with a remarkable power factor in the PEDOT film with the lowest degree of disorder.11Nsciescopu

Adult re-expression of IRSp53 rescues NMDA receptor function and social behavior in IRSp53-mutant mice

Re-expression of the insulin receptor substrate p53 (IRSp53) in adult IRSp53-mutant mice rescues behavioral and synaptic deficits, suggesting that adult re-expression may hold future therapeutic potential. IRSp53 (or BAIAP2) is an abundant excitatory postsynaptic scaffolding/adaptor protein that is involved in actin regulation and has been implicated in autism spectrum disorders, schizophrenia, and attention-deficit/hyperactivity disorder. IRSp53 deletion in mice leads to enhanced NMDA receptor (NMDAR) function and social deficits that are responsive to NMDAR inhibition. However, it remains unclear whether IRSp53 re-expression in the adult IRSp53-mutant mouse brain after the completion of brain development could reverse these synaptic and behavioral dysfunctions. Here we employed a brain-blood barrier (BBB)-penetrant adeno-associated virus (AAV) known as PHP.eB to drive adult IRSp53 re-expression in IRSp53-mutant mice. The adult IRSp53 re-expression normalized social deficits without affecting hyperactivity or anxiety-like behavior. In addition, adult IRSp53 re-expression normalized NMDAR-mediated excitatory synaptic transmission in the medial prefrontal cortex. Our results suggest that adult IRSp53 re-expression can normalize synaptic and behavioral deficits in IRSp53-mutant mice and that BBB-penetrant adult gene re-expression has therapeutic potential.11Nsciescopu

Multidentate thia-crown ethers as hyper-crosslinked macroporous adsorbent resins for the efficient Pd/Pt recovery and separation from highly acidic spent automotive catalyst leachate

Multidentate thia-crown ether (CE) diols containing different number of sulfur heteroatoms (2S-4S) were developed as ligands for Pd and Pt. Seven thia-CE diols (denoted as: 2g-2m) were synthesized at 63–93% yields through ring-opening cyclization of bis-epoxide intermediates with 1,2-benzenedithiol. Each thia-CE contains 2 –OH groups as reactive sites for adsorbent fabrication. Initial screening of thia-CE diols through liquid–liquid extraction and density functional theory (DFT) calculations reveal that bidentate (2S, 2O) dithia-CE diol 2i with cavity size Ø2i = 1.61 Å is most selective towards Pd (ØPd2+=1.56 Å) and tetradentate (4S) tetrathia-CE diol 2m (Ø2m = 1.57 Å) to Pt (ØPt2+=1.48 Å). DFT calculations indicate that size-match relationship and denticity difference dictated the coordination stability of 2i with Pd and 2m with Pt, which ultimately defined their respective selectivities. Thia-CEs 2i and 2m were subsequently fabricated as macroporous adsorbent resins (2i-X and 2m-X) via crosslinking of their bis-epoxide derivatives with ethylenediamine in porogenic PEG 400 solvent. Metal ion uptakes were Langmuir-type with high capacities (2i-X: QPd = 212 mg g−1; 2m-X: QPt = 345 mg g−1) and kinetic rates follow the pseudo-second order rate model. Metal ion uptakes are mainly due to neutral coordination with the thia-CEs (84–86%) and to some extent, due to anion complexation with ammonium groups (14–16%). Recovery of Pd by 2i-X and Pt by 2m-X can be carried out effectively and repeatedly in highly acidic feed (6 M HCl) without performance deterioration. Sequential adsorption of Pd by 2i-X and Pt by 2m-X are highly selective in the presence of base metal ions (Mg2+, Al3+, Cr3+, Mn2+, Fe3+, Ni2+, and Pb2+) making these resins ideal for the treatment of highly acidic spent auto-catalyst leachate.11Nsciescopu

Promoting angiogenesis and diabetic wound healing through delivery of protein transduction domain-BMP2 formulated nanoparticles with hydrogel

Decreased angiogenesis contributes to delayed wound healing in diabetic patients. Recombinant human bone morphogenetic protein-2 (rhBMP2) has also been demonstrated to promote angiogenesis. However, the short half-lives of soluble growth factors, including rhBMP2, limit their use in wound-healing applications. To address this limitation, we propose a novel delivery model using a protein transduction domain (PTD) formulated in a lipid nanoparticle (LNP). We aimed to determine whether a gelatin hydrogel dressing loaded with LNP-formulated PTD-BMP2 (LNP-PTD-BMP2) could enhance the angiogenic function of BMP2 and improve diabetic wound healing. In vitro, compared to the control and rhBMP2, LNP-PTD-BMP2 induced greater tube formation in human umbilical vein endothelial cells and increased the cell recruitment capacity of HaCaT cells. We inflicted large, full-thickness back skin wounds on streptozotocin-induced diabetic mice and applied gelatin hydrogel (GH) cross-linked by microbial transglutaminase containing rhBMP2, LNP-PTD-BMP2, or a control to these wounds. Wounds treated with LNP-PTD-BMP2-loaded GH exhibited enhanced wound closure, increased re-epithelialization rates, and higher collagen deposition than those with other treatments. Moreover, LNP-PTD-BMP2-loaded GH treatment resulted in more CD31- and α-SMA-positive cells, indicating greater neovascularization capacity than rhBMP2-loaded GH or GH treatments alone. Furthermore, in vivo near-infrared fluorescence revealed that LNP-PTD-BMP2 has a longer half-life than rhBMP2 and that BMP2 localizes around wounds. In conclusion, LNP-PTD-BMP2-loaded GH is a viable treatment option for diabetic wounds

Mxi1 influences cyst formation in three-dimensional cell culture

Cyst formation is a major characteristic of ADPKD and iscaused by the abnormal proliferation of epithelial cells. Renalcyst formation disrupts renal function and induces diversecomplications. The mechanism of cyst formation is unclear.mIMCD-3 cells were established to develop simple epithelialcell cysts in 3-D culture. We confirmed previously that Mxi1plays a role in cyst formation in Mxi1-deficient mice. Cysts inMxi1 transfectanted cells were showed by collagen or mebiolgels in 3-D cell culture system. Causative genes of ADPKDwere measured by q RT-PCR. Herein, Mxi1 transfectants rarelyformed a simple epithelial cyst and induced cell death.Overexpression of Mxi1 resulted in a decrease in the PKD1,PKD2 and c-myc mRNA relating to the pathway of cystformation. These data indicate that Mxi1 influences cystformation of mIMCD-3 cells in 3-D culture and that Mxi1 maycontrol the mechanism of renal cyst formation. [BMB reports2012; 45(3): 189-193