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Lin28A is an RNA-binding protein that controls mammalian development and maintenance of the pluripotency of embryonic stem cells (ESCs) via regulating the processing of the microRNA let-7. Lin28A is highly expressed in ESCs, and ectopic expression of this protein facilitates reprogramming of somatic cells to induced pluripotent stem cells. However, the mechanisms underlying the post-translational regulation of Lin28A protein stability in ESCs remain unclear. In the present study, we identified Kap1 (KRAB-associated protein 1) as a novel Lin28A-binding protein using affinity purification and mass spectrometry. Kap1 specifically interacted with the N-terminal region of Lin28A through its coiled-coil domain. Kap1 overexpression significantly attenuated Lin28A ubiquitination and increased its stability. However, small interfering RNA-mediated knockdown of Kap1 promoted the ubiquitination of Lin28A, leading to its proteasomal degradation. Trim71, an E3 ubiquitin ligase, induced Lin28A degradation and Kap1 knockdown accelerated the Trim71-dependent degradation of Lin28A. Mutation of the lysine 177 residue of Lin28A to arginine abrogated the ubiquitination and degradation of Lin28A which were accelerated by Kap1 silencing. Moreover, Kap1 overexpression led to the accumulation of Lin28A in the cytoplasm, but not in the nucleus, and reduced the levels of let-7 subtypes. These results suggest that Kap1 plays a key role in regulation of the stability of Lin28A by modulating the Trim71-mediated ubiquitination and subsequent degradation of Lin28A, thus playing a pivotal role in the regulation of ESC self-renewal and pluripotency.

We herein report the influences of glass fibers (GFs) on the thermal stability and long-term mechanical performance at elevated temperatures of thermotropic liquid crystal polyester (TLCP) composit...

A 1.3–4-GHz quadrature-phase digital delay-locked loop (DDLL) with sequential delay control and a reconfigurable delay line is designed using a 28 nm CMOS process. The time resolution of the DDLL is reduced by updating the delay code sequentially. A bidirectional shift register enables this operation with low power, resulting in bang-bang jitter that is three times smaller than that of a conventional DDLL. Conventional delay control is replaced with sequential delay control after a DDLL lock to reduce the locking time. A DDLL with a wide operation range is achieved with a reconfigurable delay line. Unlike the conventional DDLL, the minimum delay difference is adjustable in the proposed structure. To achieve a wide frequency range, the minimum delay difference of the quadrature clock is increased or decreased in three operation modes. To compensate for local variations in the CMOS process, a skew calibration circuit is implemented with the DDLL. The hardware cost of skew calibration is minimized with the proposed DDLL because it shares the subblocks for sequential delay control. The average phase difference from the quadrature clocks becomes the reference for the 90° phase for skew correction. A duty-cycle corrector (DCC) is implemented by collecting the positive edges of the quadrature-phase clocks. The DDLL consumes 6.5 mW at the maximum clock frequency of 4 GHz. The peak-to-peak jitter is improved from 15.6 to 12.5 ps with sequential delay control.

Critical limb ischemia is a condition in which tissue necrosis occurs due to arterial occlusion, resulting in limb amputation in severe cases. Both endothelial cells (ECs) and vascular smooth muscle cells (SMCs) are needed for the regeneration of peripheral arteries in ischemic tissues. However, it is difficult to isolate and cultivate primary EC and SMC from patients for therapeutic angiogenesis. Induced pluripotent stem cells (iPSCs) are regarded as useful stem cells due to their pluripotent differentiation potential. In this study, we explored the therapeutic efficacy of human iPSC‐derived EC and iPSC‐derived SMC in peripheral artery disease model. After the induction of mesodermal differentiation of iPSC, CD34+ progenitor cells were isolated by magnetic‐activated cell sorting. Cultivation of the CD34+ progenitor cells in endothelial culture medium induced the expression of endothelial markers and phenotypes. Moreover, the CD34+ cells could be differentiated into SMC by cultivation in SMC culture medium. In a murine hindlimb ischemia model, cotransplantation of EC with SMC improved blood perfusion and increased the limb salvage rate in ischemic limbs compared to transplantation of either EC or SMC alone. Moreover, cotransplantation of EC and SMC stimulated angiogenesis and led to the formation of capillaries and arteries/arterioles in vivo. Conditioned medium derived from SMC stimulated the migration, proliferation, and tubulation of EC in vitro, and these effects were recapitulated by exosomes isolated from the SMC‐conditioned medium. Together, these results suggest that iPSC‐derived SMC enhance the therapeutic efficacy of iPSC‐derived EC in peripheral artery disease via an exosome‐mediated paracrine mechanism., Co‐transplantation of the induced pluripotent stem cell (iPSC)‐derived endothelial cells and smooth muscle cells enhanced the therapeutic efficacies of endothelial cells and smooth muscle cells in a murine hindlimb ischemia model. Smooth muscle cells promoted angiogenesis and therapy of peripheral artery disease through exosome‐mediated paracrin mechanism.

For free-standing and self-doped electrode materials of energy storage devices, in this study, we investigate the microstructures and electrochemical properties of aromatic poly(ether amide) (PEA)-...

Background Esophageal tissue engineering is proposed to repair damaged esophagus, which requires peristalsis via directional alignment and movement of smooth muscle. Cell electrospinning (CE) is an effective technique to produce aligned muscle tissues by directly encapsulating living cells into micro/nanofibers. Mesenchymal stem cells (MSCs) can differentiate into smooth muscle cells (SMCs) in response to treatment with transforming growth factor-β1. In this study, we investigated the phenotypic changes of MSCs and MSC-derived SMCs via CE, and evaluated the therapeutic effect of SMC-patch for esophageal wound model. Methods MSCs and SMCs were fabricated with 2 wt % alginate and 3 wt % PEO, and the cell-laden bioink was printed and electrospun onto PCL scaffolds for random and anisotropic alignment, respectively. In in vivo test, the SMC-patch was construct by CE and the rat’s esophageal wound model was developed by tissue punching. The SMC-patch was transplanted with sutures in the esophageal defect. Results Cell electrospinning resulted in more aligned and elongated forms of MSCs and SMCs than bioprinting. SMCs aligned via cell electrospinning exhibited upregulated expression of SMC-specific markers (alpha-smooth muscle actin, calponin, SM22α, and desmin), SMC-associated extracellular matrix proteins (fibronectin, collagen types I and IV), and connexin 43, the principal gap junction protein in SMCs. The electrospun SMC was fabricated in a patch form and transplanted into a rat esophageal wound model. Transplantation of the smooth muscle patch promoted muscle regeneration and vascularization in esophageal wounds. Conclusion Taken together, these results suggest that transforming growth factor-β1-induced differentiation of MSCs to SMCs and anisotropic alignment of SMCs can be applied to engineer smooth muscle tissues and treat gastrointestinal perforation.

The effect of current stress-induced Joule heating on two different under-bump metallization (UBM) structures in Sn-Ag microbumps was investigated with current stressing at 150°C and a current density of 5 &!thinsp;× 104 A/cm2. Both Ni UBM and Cu UBM configuration microbump structures underwent extensive electromigration (EM) testing, with results revealing a longer lifetime with the Cu UBM configuration than the Ni UBM structure. The observed EM failure mechanism in the Ni UBM configuration was identified as a void formation within the bump interconnected Al trace and not due to damage accumulation inside the microbump structure. The intermetallic compound developed inside the microbump was formed and maintained its stability throughout the current stressing period. To identify the main driving force of damage accumulation in the Al trace, the current density and temperature distributions in the Sn-Ag microbumps were analyzed numerically via the finite element method. The simulation results showed higher Joule heating with the Ni UBM than the Cu UBM microbump configuration, along with the bump geometrical contribution of add-on higher Joule heating in the Ni UBM microbump structure.

Effects of solder volume on the electromigration (EM) failure mechanism of Cu/Ni/Sn-2.5Ag microbumps were systematically investigated at 150 °C with a current density of $1.5\times 10 ^{5}$ A/cm2. While the electrical resistances of Cu/Ni/Sn-Ag microbump with large solder volume increased quickly, those with small solder volume increased slowly, which depends on the difference in solder volume effect on the intermetallic compound formation mechanisms. For a structure with large solder volume, the Ni barrier layer was extensively consumed due to substantial reaction between Ni barrier and large solder volume. For a structure with small solder volume, the initial Ni barrier structure was preserved due to the limited volume of solder reacting with Ni barrier, which mainly contributes to better EM reliability of Cu/Ni/Sn-Ag microbump.

CKD-516 (Valecobulin), a vascular-disrupting agent, inhibits microtubule elongation. We evaluated the effect of CKD-516 on lung cancer cells and the underlying molecular mechanisms. The effects of S516, an active metabolite of CKD-516, were evaluated in HUVECs and three lung cancer cell lines and by a microtubule polymerization assay. Tubulin cross-linking was used to identify the binding site of S516 on tubulin, and Western blotting was performed to identify the intracellular pathways leading to cell death. Subcutaneous lung cancer xenograft models were used to assess the in vivo effect of CKD-516 on tumor growth. S516 targeted the colchicine binding site on β-tubulin. In lung cancer cells, S516 increased endoplasmic reticulum (ER) stress and induced reactive oxygen species (ROS) generation by mitochondria and the ER. In addition, CKD-516 monotherapy strongly inhibited the growth of lung cancer xenograft tumors and exerted a synergistic effect with carboplatin. The findings suggest that CKD-516 exerts an anticancer effect in company with inducing ER stress and ROS production via microtubule disruption in lung cancer cells. CKD-516 may thus have therapeutic potential for lung cancer.

The effects of annealing, electromigration, and thermomigration on volume shrinkage and voiding mechanisms of Cu/Ni/Sn-2.5Ag microbumps are systematically investigated by using in-situ scanning electron microscopy under current stressing of 1.5×105 A/cm² at 150 °C. The resistance increases rapidly in the initial stage due to formation of intermetallic compounds (IMC)s followed by a gradual increase in resistance. Growth of Ni₃Sn₄ IMCs is controlled by a diffusion-dominant mechanism, and voids and volume shrinkage are closely related to IMC phase transformation of (Au, Ni)Sn₄ to Ni₃Sn₄ in microbumps.

The enzyme flavonoid 3′,5′-hydroxylase (F3′5′H) plays an important role in producing anthocyanin pigments in soybean. Loss of function of the W1 locus encoding F3′5′H always produces white flowers. However, few color variations have been reported in wild soybean. In the present study, we isolated a new color variant of wild soybean accession (IT261811) with pinkish-white flowers. We found that the flower’s pinkish-white color is caused by w1-s3, a single recessive allele of W1. The SNP detected in the mutant caused amino acid substitution (A304S) in a highly conserved SRS4 domain of F3′5′H proteins. On the basis of the results of the protein variation effect analyzer (PROVEAN) tool, we suggest that this mutation may lead to hypofunctional F3′5′H activity rather than non-functional activity, which thereby results in its pinkish-white color.

We herein report the microstructure, optical and electrothermal properties of a series of reduced graphene oxide (RGO) thin films, which are manufactured by spin-coating (1 and 3 layers) of graphene oxide (GO) dispersion on a quartz substrate and thermal reduction at different temperatures of 800-1000 °C. The energy dispersive X-ray spectra reveal that the relative carbon content of RGO films increases from 84.3 at% to 93.5 at% with increasing the thermal reduction temperature from 800 °C and 1000 °C, whereas the oxygen content decreases from 15.7 at% to 6.5 at%. The optical transmittance of RGO1 (1 spin-coating layer) and RGO3 (3 spin-coating layers) films at 550 nm is characterized 32.7-40.8% and 6.3-12.4%, respectively, although it decreases with increasing the thermal reduction temperature. The sheet resistance of RGO1 films decreases from 5160 Ω/sq to 1220 Ω/sq with the increment of the thermal reduction temperature, whereas the sheet resistance of RGO3 films decreased from 1080 Ω/sq to 350 Ω/sq. The decreases in optical transparency and sheet resistance values of RGO thin films are due to the successful reduction of GO films with oxygen-related functional groups to electrically conductive graphene films during the thermal treatment. The RGO thin films are characterized to exhibit high performance electrothermal behavior in terms of uniform temperature distribution, controllable steady-state saturated temperatures, rapid temperature responsiveness, and electric power efficiency at input power densities.

Scleroderma is an autoimmune disease caused by the abnormal regulation of extracellular matrix synthesis and is activated by non-regulated inflammatory cells and cytokines. Echinochrome A (EchA), a natural pigment isolated from sea urchins, has been demonstrated to have antioxidant activities and beneficial effects in various disease models. The present study demonstrates for the first time that EchA treatment alleviates bleomycin-induced scleroderma by normalizing dermal thickness and suppressing collagen deposition in vivo. EchA treatment reduces the number of activated myofibroblasts expressing α-SMA, vimentin, and phosphorylated Smad3 in bleomycin-induced scleroderma. In addition, it decreased the number of macrophages, including M1 and M2 types in the affected skin, suggesting the induction of an anti-inflammatory effect. Furthermore, EchA treatment markedly attenuated serum levels of inflammatory cytokines, such as tumor necrosis factor-α and interferon-γ, in a murine scleroderma model. Taken together, these results suggest that EchA is highly useful for the treatment of scleroderma, exerting anti-fibrosis and anti-inflammatory effects.

Hexapeptide WKYMVm (Trp-Lys-Tyr-Met-Val-D-Met), a ligand of formyl peptide receptor 2, exhibits anti-inflammatory and angiogenic properties in disease models. However, the therapeutic effects of WKYMVm on hepatic fibrosis have not been evaluated to date. Therefore, we investigated whether WKYMVm exerts antifibrotic effects and induces vascular regeneration in a rat model of bile duct ligation (BDL). The antifibrotic and angiogenic effects of WKYMVm on liver regeneration in the BDL rat model were analyzed using biochemical assays, qRT-PCR, western blotting, immunofluorescence, and immunohistochemistry. To determine the effects of WKYMVm on hepatic fibrosis and angiogenesis in vitro, we measured the expression levels of fibrotic factors in hepatic stellate cells (HSCs) and angiogenic factors in human umbilical vein endothelial cells (HUVECs). WKYMVm attenuated the expression of collagen type I (Col I) and α-smooth muscle actin (α-SMA) and significantly increased the levels of angiogenetic factors in the BDL model (p &lt, 0.05). WKYMVm reduced fibrotic marker expression in transforming growth factor (TGF)-β-induced HSCs and promoted angiogenic activity through tube formation in 5-Fluorouracil (FU)-treated HUVECs (p &lt, 0.05). Also, WKYMVm administration enhanced hepatocyte proliferation in BDL rats (p &lt, 0.05). The WKYMVm alleviates hepatic fibrosis by inhibiting HSC activation and promotes hepatic regeneration via vascular remodeling. These data suggest that the WKYMVm may be a new therapeutic agent for liver fibrosis.

The determination of flower color mainly depends on the anthocyanin biosynthesis pathway and vacuolar pH; however, unlike the former, the mechanism of vacuolar acidification in soybean remains uncharacterized at the molecular level. To investigate this mechanism, we isolated four recessive purple–blue EMS-induced flower mutants from the purple flower soybean cultivar, Pungsannamul. The petals of all the mutants had increased pH compared with those of wild Pungsannamul. One of the mutants had a single nucleotide substitution in GmPH4, a regulator gene encoding an MYB transcription factor, and the substitution resulted in a premature stop codon in its first exon. The other three mutants had nucleotide substitutions in GmPH5, a single new gene that we identified by physical mapping. It corresponds to Glyma.03G262600 in chromosome 3 and encodes a proton pump that belongs to the P3A-ATPase family. The substitutions resulted in a premature stop codon, which may be a defect in the ATP-binding capacity of GmPH5 and possibly a catalytic inefficiency of GmPH5. The result is consistent with their genetic recessiveness as well as the high pH of mutant petals, suggesting that GmPH5 is directly involved in vacuolar acidification. We also found that the expression of GmPH5 and several putative “acidifying” genes in the gmph4 mutant was remarkably reduced, indicating that GmPH4 may regulate the genes involved in determining the vacuolar pH of soybean petals.

In this study, a series of thermotropic liquid crystalline polyester (TLCP)-based blends containing 1&ndash, 30 wt% poly(ethylene-co-glycidyl methacrylate) (PEGMA) were fabricated by masterbatch-assisted melt-compounding. The scanning electron microscopy (SEM) images showed a uniformly dispersed microfibrillar structure for the TLCP component in cryogenically-fractured blends, without any phase-separated domains. The FT-IR spectra showed that the carbonyl stretching bands of TLCP/PEGMA blends shifted to higher wavenumbers, suggesting the presence of specific interactions and/or grafting reactions between carboxyl/hydroxyl groups of TLCP and glycidyl methacrylate groups of PEGMA. Accordingly, the melting and crystallization temperatures of the PEGMA component in the blends were greatly lowered compared to the TLCP component. The thermal decomposition peak temperatures of the PEGMA and TLCP components in the blends were characterized as higher than those of neat PEGMA and neat TLCP, respectively. From the rheological data collected at 300 &deg, C, the shear moduli and complex viscosities for the blend with 30 wt% PEGMA were found to be much higher than those of neat PEGMA, which supports the existence of PEGMA-g-TLCP formed during the melt-compounding. The dynamic mechanical thermal analysis (DMA) analyses demonstrated that the storage moduli of the blends decreased slightly with the PEGMA content up to 3 wt%, increased at the PEGMA content of 5 wt%, and decreased again at PEGMA contents above 7 wt%. The maximum storage moduli for the blend with 5 wt% PEGMA are interpreted to be due to the reinforcing effect of PEGMA-g-TLCP copolymers.

In this study, a series of thermotropic liquid crystalline polyester (TLCP)-based blends containing 1–30 wt% poly(ethylene-co-glycidyl methacrylate) (PEGMA) were fabricated by masterbatch-assisted melt-compounding. The scanning electron microscopy (SEM) images showed a uniformly dispersed microfibrillar structure for the TLCP component in cryogenically-fractured blends, without any phase-separated domains. The FT-IR spectra showed that the carbonyl stretching bands of TLCP/PEGMA blends shifted to higher wavenumbers, suggesting the presence of specific interactions and/or grafting reactions between carboxyl/hydroxyl groups of TLCP and glycidyl methacrylate groups of PEGMA. Accordingly, the melting and crystallization temperatures of the PEGMA component in the blends were greatly lowered compared to the TLCP component. The thermal decomposition peak temperatures of the PEGMA and TLCP components in the blends were characterized as higher than those of neat PEGMA and neat TLCP, respectively. From the rheological data collected at 300 °C, the shear moduli and complex viscosities for the blend with 30 wt% PEGMA were found to be much higher than those of neat PEGMA, which supports the existence of PEGMA-g-TLCP formed during the melt-compounding. The dynamic mechanical thermal analysis (DMA) analyses demonstrated that the storage moduli of the blends decreased slightly with the PEGMA content up to 3 wt%, increased at the PEGMA content of 5 wt%, and decreased again at PEGMA contents above 7 wt%. The maximum storage moduli for the blend with 5 wt% PEGMA are interpreted to be due to the reinforcing effect of PEGMA-g-TLCP copolymers.

The determination of flower color mainly depends on the anthocyanin biosynthesis pathway and vacuolar pH; however, unlike the former, the mechanism of vacuolar acidification in soybean remains uncharacterized at the molecular level. To investigate this mechanism, we isolated four recessive purple–blue EMS-induced flower mutants from the purple flower soybean cultivar, Pungsannamul. The petals of all the mutants had increased pH compared with those of wild Pungsannamul. One of the mutants had a single nucleotide substitution in GmPH4, a regulator gene encoding an MYB transcription factor, and the substitution resulted in a premature stop codon in its first exon. The other three mutants had nucleotide substitutions in GmPH5, a single new gene that we identified by physical mapping. It corresponds to Glyma.03G262600 in chromosome 3 and encodes a proton pump that belongs to the P3A-ATPase family. The substitutions resulted in a premature stop codon, which may be a defect in the ATP-binding capacity of GmPH5 and possibly a catalytic inefficiency of GmPH5. The result is consistent with their genetic recessiveness as well as the high pH of mutant petals, suggesting that GmPH5 is directly involved in vacuolar acidification. We also found that the expression of GmPH5 and several putative “acidifying” genes in the gmph4 mutant was remarkably reduced, indicating that GmPH4 may regulate the genes involved in determining the vacuolar pH of soybean petals.

Recently, eco-friendly and biologically harmless products of waterborne polyurethane (WPU) instead of solvent-borne polyurethane have been strongly progressed in both industries and research areas. Accordingly, we developed a WPU-based macroporous sponge as a skin tissue engineering matrix. Also, the WPU dispersion in water was modified by using a foaming agent in order to create creamy emulsion resulting in enlarging surface area wherein cells could adhere, grow, and proliferate. We investigated the effect of a foaming agent on the morphology of surface and internal structure, wettability. In vitro studies also confirmed enhanced adherence and proliferation of cells with increased metabolic rate. These results proved that the use of foaming agent could alter the internal structure, surface property, and biocompatibility.

For attaining flexible and self-standing electrode materials for advanced energy storage devices, we herein report the fabrication and electrochemical properties of carbon nanofibers (CNFs) derived from polyimide (PI) and lignin precursors with different mass ratios (10/0, 9/1, 8/2, and 7/3) via electrospinning and carbonization at 1000 °C. The electron microscopic and photographic images exhibit that the average diameter and flexibility of PI/lignin-derived CNFs decreases and increases, respectively, with increasing the lignin mass ratio in the precursors. The EDS, XRD and Raman analyses confirm that PI/lignin-derived CNFs possess a partially ordered graphitic structure with oxygen self-doping. The electrical conductivity of the CNFs increases from 1.5 S/cm to 2.8 S/cm with the increment of the lignin mass ratio in the precursors. Accordingly, PI/lignin (7/3)-derived CNF is found to have the most excellent electrochemical properties from the analyses using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) test, and electrochemical impedance spectroscopy (EIS). For a symmetric two-electrode supercapacitor based on PI/lignin (7/3)-derived CNFs, high specific capacitance of 83.6 F/g at 1 A/g, power density of 5000 W/kg, energy density of 13.3 Wh/kg, and capacitance retention of ∼100% after 1000 GCD cycle are attained.

Ni barrier symmetry effect on the electromigration (EM) failure mechanism of Cu/Sn–Ag microbump were systematically investigated by studying the intermetallic compound (IMC) growth characteristics at 150 °C with a current density of 1.5 × 105 A/cm2. In the symmetric Ni barrier structure, Cu diffusion to Sn–Ag solder was restricted by the Ni barrier at both interfaces and the Ni3Sn4 phase formed by the inter-diffusion between Ni and Sn atoms just after bonding, which was gradually transformed to (Ni,Cu)3Sn4 phase and later to (Cu,Ni)6Sn5 during current stressing with relatively slow resistance increase with time. By the way, in the asymmetric structure, extensive Cu6Sn5 phase grew by the inter-diffusion between Cu and Sn atoms due to there is no Ni barrier at the upper interface, which was rapidly transformed into only Cu6Sn5 and Cu3Sn IMCs during electron downward flow, with relatively fast resistance increase with time. Therefore, the symmetric Ni barrier structure is very effective in restricting extensive IMC reactions during EM of Cu-solder microbump structure.

2,3-Dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) saponins are one of the major saponin groups that are widely distributed in legumes such as pea, barrel medic, chickpea, and soybean. The steps involved in DDMP saponin biosynthesis remain uncharacterized at the molecular level. We isolated two recessive mutants that lack DDMP saponins from an ethyl methanesulfonate-induced mutant population of soybean cultivar Pungsannamul. Segregation analysis showed that the production of DDMP saponins is controlled by a single locus, named Sg-9. The locus was physically mapped to a 130-kb region on chromosome 16. Nucleotide sequence analysis of candidate genes in the region revealed that each mutant has a single-nucleotide polymorphism in the Glyma.16G033700 encoding a UDP-glycosyltransferase UGT73B4. Enzyme assays and mass spectrum-coupled chromatographic analysis reveal that the Sg-9 protein has glycosyltransferase activity, converting sapogenins and group B saponins to glycosylated products, and that mutant proteins had only partial activities. The tissue-specific expression profile of Sg-9 matches the accumulation pattern of DDMP saponins. This is the first report on a new gene and its function in the biosynthesis of DDMP saponins. Our findings indicate that Sg-9 encodes a putative DDMP transferase that plays a critical role in the biosynthesis of DDMP saponins.

Circulating angiogenic cells (CACs) have been implicated in the repair of ischemic tissues, and their mobilization from bone marrow is known to be regulated by the activations of chemokine receptors, including CXCR2 and CXCR4. This study was conducted to investigate the role of N-acetylated proline-glycine-proline (Ac-PGP; a collagen-derived chemotactic tripeptide) on CAC mobilization and its therapeutic potential for the treatment of peripheral artery diseases. Ac-PGP was administered daily to a murine hind limb ischemia model, and the effects of Ac-PGP on blood perfusion and CAC mobilization (Sca1+Flk1+ cells) into peripheral blood were assessed. Intramuscular administration of Ac-PGP significantly improved ischemic limb perfusion and increased limb salvage rate by increasing blood vessel formation, whereas Ac-PGP-induced blood perfusion and angiogenesis in ischemic limbs were not observed in CXCR2-knockout mice. In addition, Ac-PGP-induced CAC mobilization was found to occur in wild-type mice but not in CXCR2-knockout mice. Transplantation of bone marrow from green fluorescent protein (GFP) transgenic mice to wild-type mice showed bone marrow-derived cells homed to ischemic limbs after Ac-PGP administration and that GFP-positive cells contributed to the formation of ILB4-positive capillaries and α smooth muscle actin (α-SMA)-positive arteries. These results suggest CXCR2 activation in bone marrow after Ac-PGP administration improves blood perfusion and reduces tissue necrosis by inducing CAC mobilization. These findings suggest a new pharmaceutical basis for the treatment of critical limb ischemia. Stem Cells Translational Medicine 2019;8:236&246

3D cell-printing technique has been under spotlight as an appealing biofabrication platform due to its ability to precisely pattern living cells in pre-defined spatial locations . In skin tissue engineering , a major remaining challenge is to seek for a suitable source of bioink capable of supporting and stimulating printed cells for tissue development. However, current bioinks for skin printing rely on homogeneous biomaterials , which has several shortcomings such as insufficient mechanical properties and recapitulation of microenvironment . In this study, we investigated the capability of skin-derived extracellular matrix (S-dECM) bioink for 3D cell printing-based skin tissue engineering. S-dECM was for the first time formulated as a printable material and retained the major ECM compositions of skin as well as favorable growth factors and cytokines. This bioink was used to print a full thickness 3D human skin model. The matured 3D cell-printed skin tissue using S-dECM bioink was stabilized with minimal shrinkage, whereas the collagen-based skin tissue was significantly contracted during in vitro tissue culture. This physical stabilization and the tissue-specific microenvironment from our bioink improved epidermal organization, dermal ECM secretion, and barrier function. We further used this bioink to print 3D pre-vascularized skin patch able to promote in vivo wound healing. In vivo results revealed that endothelial progenitor cells (EPCs)-laden 3D-printed skin patch together with adipose-derived stem cells (ASCs) accelerates wound closure, re-epithelization, and neovascularization as well as blood flow. We envision that the results of this paper can provide an insightful step towards the next generation source for bioink manufacturing.

Atrial natriuretic peptide (ANP) is a powerful vasodilating peptide secreted by cardiac muscle cells, and endothelial progenitor cells (EPCs) have been reported to stimulate cutaneous wound healing by mediating angiogenesis. To determine whether ANP can promote the EPC-mediated repair of injured tissues, we examined the effects of ANP on the angiogenic properties of EPCs and on cutaneous wound healing. In vitro, ANP treatment enhanced the migration, proliferation, and endothelial tube-forming abilities of EPCs. Furthermore, small interfering RNA-mediated silencing of natriuretic peptide receptor-1, which is a receptor for ANP, abrogated ANP-induced migration, tube formation, and proliferation of EPCs. In a murine cutaneous wound model, administration of either ANP or EPCs had no significant effect on cutaneous wound healing or angiogenesis in vivo, whereas the coadministration of ANP and EPCs synergistically potentiated wound healing and angiogenesis. In addition, ANP promoted the survival and incorporation of transplanted EPCs into newly formed blood vessels in wounds. These results suggest ANP accelerates EPC-mediated cutaneous wound healing by promoting the angiogenic properties and survival of transplanted EPCs.