Theoretical study of acene-bridged dyes for dye-sensitized solar cells.

The electronic structures and absorption spectra for a series of acene-based organic dyes and the adsorption energy and optical properties for these dyes adsorbed on (TiO2)38 have been investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. The effects of acene units and different substitution positions of electron donors on the optoelectronic properties of the acene-modified dyes are demonstrated. The photophysical properties of tetracene- and pentacene-based dyes are found to be tuned by changing the size of acene and the substitution position of the donor. The donor sites have a significant influence on the absorption wavelength mainly because of different molecular orbital (MO) contributions of the highest occupied molecular orbital (HOMO) on the bridging acene units, and the increasing MO contribution would lead to the red shift in the absorption spectra. Meanwhile, the donor is located close to the center of the π-conjugated bridge, and the absorption spectra are extended. The adsorption energy and optical properties of tetracene- and pentacene-based dyes adsorbed on (TiO2)38 suggest that acene-bridged dyes could be adsorbed on the TiO2 surface and inject electrons into semiconductors effectively. Then the results obtained from the hexacene-based dyes confirm the conclusions proposed from the tetracene- and pentence-based dyes. This study will provide a useful reference to the future design and optimization of acene dyes for dye-sensitized solar cell applications.

αßγ-Synuclein triple knockout mice reveal age-dependent neuronal dysfunction.

Synucleins are a vertebrate-specific family of abundant neuronal proteins. They comprise three closely related members, α-, ß-, and γ-synuclein. α-Synuclein has been the focus of intense attention since mutations in it were identified as a cause for familial Parkinson's disease. Despite their disease relevance, the normal physiological function of synucleins has remained elusive. To address this, we generated and characterized αßγ-synuclein knockout mice, which lack all members of this protein family. Deletion of synucleins causes alterations in synaptic structure and transmission, age-dependent neuronal dysfunction, as well as diminished survival. Abrogation of synuclein expression decreased excitatory synapse size by ∼30% both in vivo and in vitro, revealing that synucleins are important determinants of presynaptic terminal size. Young synuclein null mice show improved basic transmission, whereas older mice show a pronounced decrement. The late onset phenotypes in synuclein null mice were not due to a loss of synapses or neurons but rather reflect specific changes in synaptic protein composition and axonal structure. Our results demonstrate that synucleins contribute importantly to the long-term operation of the nervous system and that alterations in their physiological function could contribute to the development of Parkinson's disease.

Heparin-based sericin hydrogel-encapsulated basic fibroblast growth factor for in vitro and in vivo skin repair.

The treatment of full-thickness cutaneous wounds remains a significant challenge in clinical therapeutics. Exogenous growth factor (GF) has been applied in clinics to promote wound healing. However, the retention of GF on the wound bed after its direct application to the wound surface is difficult. Moreover, growth factors (GFs) are always inactivated in the complex wound healing microenvironment due to various factors, which significantly decrease the therapeutic effect. Sericin hydrogel (S) can be used as an effective carrier for GFs owing to its low immunogenicity, good biocompatibility, and good healing-promoting ability. Here, we designed a heparin-based sericin hydrogel (HS) -encapsulated basic fibroblast growth factor (bFGF-HS) to facilitate wound healing and skin regeneration. The hydrogel exhibited a three-dimensional (3D) microporous structure, excellent biodegradability, good adhesiveness, and low cytotoxicity. In vitro release of bFGF from bFGF-HS coacervates revealed that bFGF-HS might control the release of bFGF within 25 days through heparin regulation. bFGF-HS significantly promoted vascularization and re-epithelialization and improved collagen deposition, ultimately accelerating wound healing in vivo in mice. bFGF-HS treated wounds were also found to have more hair follicles and milder inflammatory reactions. Overall, this study provides a new therapeutic approach for full-thickness skin defect wounds using bFGF-HS.

Effect of vitamin D3 supplementation in winter on physical performance of university students: a one-month randomized controlled trial.

BACKGROUND: There is epidemiological evidence which suggests an association between 25-hydroxyvitamin D [25(OH)D] levels and bone and muscle function; however, it is unclear whether vitamin D supplementation has an added benefit beyond bone health. Here, we investigated the effects of vitamin D3 supplementation (1 month) on physical performance in Chinese university students in winter. METHODS: One hundred and seventeen eligible subjects with 25(OH)D (19.2 ± 7.8 ng/mL) were randomly assigned to either vitamin D3 supplement (N = 56; 1000 IU/day) or the control (N = 61) group for 1 month. Pre- and post-measurements included: 1) serum levels of 25(OH)D; 2) musculoskeletal and pulmonary function [vertical jump height (VJH) and right handgrip strength (RHS), forced vital capacity (FVC), and forced expiratory volume at 1s (FEV1)]; 3) bone turnover markers [parathyroid hormone (PTH), n-terminal osteocalcin (N-MID), and calcium]; 4) hemoglobin-related parameters [hemoglobin (Hb), hematocrit (HCT), red blood cells (RBC), and red cell distribution width (RDW)]; 5) lipid parameters [total triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C)]; 6) Fatigue-related indicators [serum creatine kinase (CK), lactate dehydrogenase (LDH), and total testosterone (T)]. In addition, aerobic capacity was assessed by measuring maximal oxygen uptake (VO2max) at baseline. RESULTS: During wintertime, supplementation with 1000 IU/d of vitamin D3 significantly increased serum 25(OH)D levels (from 18.85 ± 7.04 to 26.98 ± 5.88 ng/mL, p < 0.05), accompanied by a decrease of PTH (p < 0.05). However, vitamin D3 supplementation did not significantly impact the physical performance, serum lipid parameters, and bone turnover markers of students. Furthermore, 25(OH)D was found to be positively correlated with VJH and negatively correlated with PTH and TC at the beginning and end of the study (p < 0.05). In addition, the multiple linear regression analysis showed that 25(OH)D combined with athletic, gender, height, weight, Hb, and FVC could account for 84.0% of the VO2max value. CONCLUSIONS: The study demonstrated that one-month of 1000 IU/d of vitamin D3 supplementation during the winter had beneficial effects on 25(OH)D status and PTH. However, vitamin D3 intervention was not sufficient to improve physical performance. Furthermore, 25(OH)D levels combined with athletic, Hb and FVC could be a predictor of VO2max.

Mesenchymal stem cells pretreated with proinflammatory cytokines accelerate skin wound healing by promoting macrophages migration and M2 polarization.

Introduction: Numerous studies have shown that mesenchymal stem cells (MSCs) promote cutaneous wound healing via paracrine signaling. Our previous study found that the secretome of MSCs was significantly amplified by treatment with IFN-γ and TNF-α (IT). It has been known that macrophages are involved in the initiation and termination of inflammation, secretion of growth factors, phagocytosis, cell proliferation and collagen deposition in wound, which is the key factor during wound healing. In the present study, we used a unique supernatant of MSCs from human umbilical cord-derived MSCs (UC-MSCs) pretreated with IT, designated S-IT MSCs, to explore whether S-IT MSCs have a better effect on improving wound healing by improving the biological function of macrophages than the control supernatant of MSCs (S-MSCs). Methods: In the present study, we used a unique supernatant of MSCs pretreated with IT subcutaneously injected into a mice total skin excision. We evaluated the effect of S-IT MSCs on wound healing and the quality of wound repair via promoting macrophages migration and M2 polarization in vivo. In addition, the effect of S-IT MSCs on macrophages migration, converting toward M2 phenotype and phagocytosis were also investigated in vitro. Results: Indeed, S-IT MSCs were found to be more potent in promoting macrophage migration, M2 polarization, phagocytosis, and promoting wound closure than S-MSCs during the wound repair. High levels of CCL2 and IL-6 were found in S-IT MSCs, which indicated that the optimization of macrophage function by S-IT MSCs may be achieved through their high expression of CCL2 and IL-6. Conclusions: Our results suggest that the beneficial paracrine effect of MSCs on wound healing can be amplified by pretreatment with IT, which may represent a new strategy for optimizing the therapeutic effect of MSCs on wound healing.

Mesenchymal stromal cells pretreated with proinflammatory cytokines enhance skin wound healing via IL-6-dependent M2 polarization.

BACKGROUND: Numerous studies have shown that mesenchymal stromal cells (MSCs) promote cutaneous wound healing via paracrine signaling. Our previous study found that the secretome of MSCs was significantly amplified by treatment with IFN-γ and TNF-α (IT). It has been known that macrophages are involved in the initiation and termination of inflammation, secretion of growth factors, phagocytosis, cell proliferation, and collagen deposition in wound, which is the key factor during wound healing. In this study, we aim to test whether the supernatant of MSCs pretreated with IT (S-IT MSCs) possesses a more pronounced effect on improving wound healing and describe the interplay between S-IT MSCs and macrophages as well as the potential mechanism in skin wound healing. METHODS: In the present study, we used a unique supernatant of MSCs from human umbilical cord-derived MSCs (UC-MSCs) pretreated with IT, designated S-IT MSCs, subcutaneously injected into a mice total skin excision. We evaluated the effect of S-IT MSCs on the speed and quality of wound repair via IT MSCs-derived IL-6-dependent M2 polarization in vivo by hematoxylin-eosin staining (H&E), immunohistochemistry (IHC), immunofluorescence (IF), Masson's trichrome staining, Sirius red staining, quantitative real-time PCR (qPCR). In addition, the effect of S-IT MSCs on the polarization of macrophages toward M2 phenotype and the potential mechanism of it were also investigated in vitro by flow cytometry (FCM), enzyme-linked immunosorbent assay (ELISA), tube formation assay, and western blot analysis. RESULTS: Compared with control supernatant (S-MSCs), our H&E and IF results showed that S-IT MSCs were more effectively in promoting macrophages convert to the M2 phenotype and enhancing phagocytosis of M2 macrophages. Meanwhile, the results of tube formation assay, IHC, Masson's trichrome staining, Sirius red staining showed that the abilities of M2 phenotype to promote vascularization and collagen deposition were significantly enhanced by S-IT MSCs-treated, thereby accelerating higher quality wound healing. Further, our ELISA, FCM, qPCR and western blot results showed that IL-6 was highly enriched in S-IT MSCs and acted as a key regulator to induce macrophages convert to the M2 phenotype through IL-6-dependent signaling pathways, ultimately achieving the above function of promoting wound repair. CONCLUSIONS: These findings provide the first evidence that the S-IT MSCs is more capable of eliciting M2 polarization of macrophages via IL-6-dependent signaling pathways and accelerating wound healing, which may represent a new strategy for optimizing the therapeutic effect of MSCs on wound healing.

Changing dendritic field size of mouse retinal ganglion cells in early postnatal development.

During early postnatal development, dendrites of retinal ganglion cells (RGCs) extend and branch in the inner plexiform layer to establish the adult level of stratification, pattern of branching, and coverage. Many studies have described the branching patterns, transient features, and regulatory factors of stratification of the RGCs. The rate of RGC dendritic field (DF) expansion relative to the growing retina has not been systematically investigated. In this study, we used two methods to examine the relative expansion of RGC DFs. First, we measured the size of RGC DFs and the diameters of the eyeballs at several postnatal stages. We compared the measurements with the RGC DF sizes calculated from difference of the eyeball sizes based on a linear expansion assumption. Second, we used the number of cholinergic amacrine cells (SACs) circumscribed by the DFs of RGCs at corresponding time points as an internal ruler to assess the size of DFs. We found most RGCs exhibit a phase of faster expansion relative to the retina between postnatal day 8 (P8) and P13, followed by a phase of retraction between P13 and adulthood. The morphological alpha cells showed the faster growing phase but not the retraction phase, whereas the morphological ON-OFF direction selective ganglion cells expanded in the same pace as the growing retina. These findings indicate different RGCs show different modes of growth, whereas most subtypes exhibit a fast expansion followed by a retraction phase to reach the adult size.

The immune protein CD3zeta is required for normal development of neural circuits in the retina.

Emerging evidence suggests that immune proteins regulate activity-dependent synapse formation in the central nervous system (CNS). Mice with mutations in class I major histocompatibility complex (MHCI) genes have incomplete eye-specific segregation of retinal ganglion cell (RGC) axon projections to the CNS. This effect has been attributed to causes that are nonretinal in origin. We show that a key component of MHCI receptor, CD3zeta, is expressed in RGCs. CD3zeta-deficient mice have reduced RGC dendritic motility, an increase in RGC dendritic density, and a selective defect of glutamate-receptor-mediated synaptic activity in the retina. Disrupted RGC synaptic activity and dendritic motility is associated with a failure of eye-specific segregation of RGC axon projections to the CNS. These results provide direct evidence of an unrecognized requirement for immune proteins in the developmental regulation of RGC synaptic wiring and indicate a possible retinal origin for the disruption of eye-specific segregation found in immune-deficient mice.

Development of the mouse retina: emerging morphological diversity of the ganglion cells.

The time course and regulatory mechanisms of dendritic development are subjects of intense interest. We approached these problems by investigating dendritic morphology of retinal ganglion cells (RGCs) at four early postnatal stages. The RGCs develop from a diffusely stratified and poorly differentiated group at birth (P0), to 16 distinct, morphologically well-defined subtypes before eye opening (P13). Even before bipolar cells make synaptic contacts with the RGCs (P8), most adultlike RGC subtypes are already present. Similar to previous studies in other mammalian species, our results indicate that the initiation of the RGC morphological maturation is independent of light stimulation and of formation of glutamatergic synapses. This study narrowed down the window of RGCs morphological maturation and highlighted a few early postnatal events as potential factors controlling the developmental process. Because mouse is the most popular mammalian model for genetic manipulation, this study provided a foundation for further exploring regulatory mechanisms of RGC dendritic development.