Effects of Urban Vibrancy on an Urban Eco-Environment: Case Study on Wuhan City.

In the context of rapid urbanisation and an emerging need for a healthy urban environment, revitalising urban spaces and its effects on the urban eco-environment in Chinese cities have attracted widespread attention. This study assessed urban vibrancy from the dimensions of density, accessibility, liveability, diversity, and human activity, with various indicators using an adjusted spatial TOPSIS (technique for order preference by similarity to an ideal solution) method. The study also explored the effects of urban vibrancy on the urban eco-environment by interpreting PM 2.5 and land surface temperature using "big" and "dynamic" data, such as those from mobile and social network data. Thereafter, spatial modelling was performed to investigate the influence of urban vibrancy on air pollution and temperature with inverted and extracted remote sensing data. This process identified spatial heterogeneity and spatial autocorrelation. The majority of the dimensions, such as density, accessibility, liveability, and diversity, are negatively correlated with PM 2.5, thereby indicating that the advancement of urban vibrancy in these dimensions potentially improves air quality. Conversely, improved accessibility increases the surface temperature in most of the districts, and large-scale infrastructure construction generally contributes to the increase. Diversity and human activity appear to have a cooling effect. In the future, applying spatial heterogeneity is advised to assess urban vibrancy and its effect on the urban eco-environment, to provide valuable references for spatial urban planning, improve public health and human wellbeing, and ensure sustainable urban development.

Arabidopsis thaliana calmodulin-like protein CML24 regulates pollen tube growth by modulating the actin cytoskeleton and controlling the cytosolic Ca(2+) concentration.

Cytosolic free calcium ([Ca(2+)]cyt), which is essential during pollen germination and pollen tube growth, can be sensed by calmodulin-like proteins (CMLs). The Arabidopsis thaliana genome encodes over 50 CMLs, the physiological role(s) of most of which are unknown. Here we show that the gene AtCML24 acts as a regulator of pollen germination and pollen tube extension, since the pollen produced by loss-of-function mutants germinated less rapidly than that of wild-type (WT) plants, the rate of pollen tube extension was slower, and the final length of the pollen tube was shorter. The [Ca(2+)]cyt within germinated pollen and extending pollen tubes produced by the cml24 mutant were higher than their equivalents in WT plants, and pollen tube extension was less sensitive to changes in external [K(+)] and [Ca(2+)]. The pollen and pollen tubes produced by cml24 mutants were characterized by a disorganized actin cytoskeleton and lowered sensitivity to the action of latrunculin B. The observations support an interaction between CML24 and [Ca(2+)]cyt and an involvement of CML24 in actin organization, thereby affecting pollen germination and pollen tube elongation.

Histone deacetylase 4 selectively contributes to podocyte injury in diabetic nephropathy.

Studies have highlighted the importance of histone deacetylase (HDAC)-mediated epigenetic processes in the development of diabetic complications. Inhibitors of HDAC are a novel class of therapeutic agents in diabetic nephropathy, but currently available inhibitors are mostly nonselective inhibit multiple HDACs, and different HDACs serve very distinct functions. Therefore, it is essential to determine the role of individual HDACs in diabetic nephropathy and develop HDAC inhibitors with improved specificity. First, we identified the expression patterns of HDACs and found that, among zinc-dependent HDACs, HDAC2/4/5 were upregulated in the kidney from streptozotocin-induced diabetic rats, diabetic db/db mice, and in kidney biopsies from diabetic patients. Podocytes treated with high glucose, advanced glycation end products, or transforming growth factor-ß (common detrimental factors in diabetic nephropathy) selectively increased HDAC4 expression. The role of HDAC4 was evaluated by in vivo gene silencing by intrarenal lentiviral gene delivery and found to reduce renal injury in diabetic rats. Podocyte injury was associated with suppressing autophagy and exacerbating inflammation by HDAC4-STAT1 signaling in vitro. Thus, HDAC4 contributes to podocyte injury and is one of critical components of a signal transduction pathway that links renal injury to autophagy in diabetic nephropathy.

Novel role of NOD2 in mediating Ca2+ signaling: evidence from NOD2-regulated podocyte TRPC6 channels in hyperhomocysteinemia.

Although hyperhomocysteinemia (hHcys) has been recognized as an important independent risk factor in the progression of end-stage renal disease and in the development of cardiovascular complications related to end-stage renal disease, the mechanisms triggering the pathogenic actions of hHcys are not yet fully understood. The present study was designed to investigate the contribution of nucleotide-binding oligomerization domain containing 2 (NOD2), an intracellular innate immunity mediator, to the development of glomerulosclerosis in hHcys. Our results showed that NOD2 deficiency ameliorated renal injury in mice with hHcys. We further discovered the novel role of NOD2 in mediating Ca(2+) signaling and found that homocysteine-induced NOD2 expression enhanced transient receptor potential cation channel 6 (TRPC6) expression and TRPC6-mediated calcium influx and currents, leading to intracellular Ca(2+) release, ultimately resulting in podocyte cytoskeleton rearrangement and apoptosis. Moreover, we found that nephrin expression was downregulated dependently by NOD2, and overexpression of nephrin attenuated homocysteine-induced TRPC6 expression in podocytes. The results add evidence to support the essential role of nephrin in mediating NOD2-induced TRPC6 expression in hHcys. In conclusion, our results for the first time establish a previously unknown function of NOD2 for the regulation of TRPC6 channels, suggesting that TRPC6-dependent Ca(2+) signaling is one of the critical signal transduction pathways that links innate immunity mediator NOD2 to podocyte injury. Pharmacological targeting of NOD2 signaling pathways at multiple levels may help design a new approach to develop therapeutic strategies for treatment of hHcys-associated end-stage renal disease.

NOD2 promotes renal injury by exacerbating inflammation and podocyte insulin resistance in diabetic nephropathy.

An increasing number of clinical and animal model studies indicate that activation of the innate immune system and inflammatory mechanisms are important in the pathogenesis of diabetic nephropathy. Nucleotide-binding oligomerization domain containing 2 (NOD2), a member of the NOD-like receptor family, plays an important role in innate immune response. Here we explore the contribution of NOD2 to the pathogenesis of diabetic nephropathy and found that it was upregulated in kidney biopsies from diabetic patients and high-fat diet/streptozotocin-induced diabetic mice. Further, NOD2 deficiency ameliorated renal injury in diabetic mice. In vitro, NOD2 induced proinflammatory response and impaired insulin signaling and insulin-induced glucose uptake in podocytes. Moreover, podocytes treated with high glucose, advanced glycation end-products, tumor necrosis factor-α, or transforming growth factor-ß (common detrimental factors in diabetic nephropathy) significantly increased NOD2 expression. NOD2 knockout diabetic mice were protected from the hyperglycemia-induced reduction in nephrin expression. Further, knockdown of NOD2 expression attenuated high glucose-induced nephrin downregulation in vitro, supporting an essential role of NOD2 in mediating hyperglycemia-induced podocyte dysfunction. Thus, NOD2 is one of the critical components of a signal transduction pathway that links renal injury to inflammation and podocyte insulin resistance in diabetic nephropathy.

Arabidopsis VILLIN2 and VILLIN3 act redundantly in sclerenchyma development via bundling of actin filaments.

The organization of the actin cytoskeleton has been implicated in sclerenchyma development. However, the molecular mechanisms linking the actin cytoskeleton to this process remain poorly understood. In particular, there have been no studies showing that direct genetic manipulation of the actin cytoskeleton affects sclerenchyma development. Villins belong to the villin/gelsolin/fragmin superfamily and are versatile actin-modifying proteins. Several recent studies have implicated villins in tip growth of single cells, but how villins act in multicellular plant development remains largely unknown. Here, we found that two closely related villin isovariants from Arabidopsis, VLN2 and VLN3, act redundantly in sclerenchyma development. Detailed analysis of cross-sections from inflorescence stems of vln2 vln3 double mutant plants revealed a reduction in stem size and in the number of vascular bundles; however, no defects in synthesis of the secondary cell wall were detected. Surprisingly, the vln2 vln3 double mutation did not affect cell elongation of inter-fascicular fibers. Biochemical analyses showed that recombinant VLN2 was able to cap, sever and bundle actin filaments, similar to VLN3. Consistent with these biochemical activities, loss of function of VLN2 and VLN3 resulted in a decrease in the amount of F-actin and actin bundles in plant cells. Collectively, our findings demonstrate that VLN2 and VLN3 act redundantly in sclerenchyma development via bundling of actin filaments.

Molecular characterization and functional analysis of Cashmere goat mammalian target of rapamycin.

The mammalian target of rapamycin (mTOR) is an evolutionarily conserved protein kinase that belongs to the phosphatidylinositol kinase-related kinase family. We describe our molecular characterization of mTOR and its function (GenBank accession HM114224) in Cashmere goat (Capra hircus). The goat mTOR complementary DNA is 8617 bp, comprising an open reading frame of 7650 bp--corresponding to a polypeptide of 2549 amino acids--and a 909 bp 3' untranslated region with a polyA tract and a polyadenylation signal at nucleotides 8575-8580. In a bioinformatics analysis, goat mTOR has typical sites of activity and domains. mTOR mRNA was measured in brain, heart, testis, liver, spleen, kidney, and lung by real-time polymerase chain reaction, and the expression of mTOR in fetal fibroblasts was detected by western blot. The viability of fetal fibroblasts was inhibited on treatment with CCI-779, a specific inhibitor of mTOR. Our data supplied evidence that the transcription of mTOR was detected in the seven tissues in Cashmere goat, and mTOR protein was translated in fetal fibroblasts. The proliferation of fetal fibroblasts decreases on inhibition of mTOR.

Arabidopsis VILLIN5, an actin filament bundling and severing protein, is necessary for normal pollen tube growth.

A dynamic actin cytoskeleton is essential for pollen germination and tube growth. However, the molecular mechanisms underlying the organization and turnover of the actin cytoskeleton in pollen remain poorly understood. Villin plays a key role in the formation of higher-order structures from actin filaments and in the regulation of actin dynamics in eukaryotic cells. It belongs to the villin/gelsolin/fragmin superfamily of actin binding proteins and is composed of six gelsolin-homology domains at its core and a villin headpiece domain at its C terminus. Recently, several villin family members from plants have been shown to sever, cap, and bundle actin filaments in vitro. Here, we characterized a villin isovariant, Arabidopsis thaliana VILLIN5 (VLN5), that is highly and preferentially expressed in pollen. VLN5 loss-of-function retarded pollen tube growth and sensitized actin filaments in pollen grains and tubes to latrunculin B. In vitro biochemical analyses revealed that VLN5 is a typical member of the villin family and retains a full suite of activities, including barbed-end capping, filament bundling, and calcium-dependent severing. The severing activity was confirmed with time-lapse evanescent wave microscopy of individual actin filaments in vitro. We propose that VLN5 is a major regulator of actin filament stability and turnover that functions in concert with oscillatory calcium gradients in pollen and therefore plays an integral role in pollen germination and tube growth.