A Low Interleukin-2 Receptor Signaling Threshold Supports the Development and Homeostasis of T Regulatory Cells

SummaryInterleukin-2 receptor (IL-2R) signaling is essential for T regulatory (Treg) cell development and homeostasis. Here, we show that expression of IL-2Rβ chains that lack tyrosine residues important for the association of the adaptor Shc and the transcription factor STAT5 in IL-2Rβ-deficient mice resulted in production of a normal proportion of natural Treg cells that suppressed severe autoimmunity related with deficiency in IL-2 or IL-2R. These mutant IL-2Rβ chains supported suboptimal and transient STAT5 activation that upregulate the transcription factor Foxp3 to normal amounts in natural, but not induced, Treg cells. Nevertheless, gene expression profiling revealed many targets in peripheral natural Treg cells that were IL-2 dependent and a substantial overlap between the Treg cell IL-2-dependent gene program and the Treg cell transcriptional signature. Collectively, these findings demonstrate that a critical, and perhaps minor, subset of IL-2-dependent targets is indexed to a low IL-2R signaling threshold and that a substantial proportion of the Treg cell gene program is regulated by IL-2

A taxonomic revision of three Chinese spurless species of genus Epimedium L. (Berberidaceae)

Due to some common or similar features (e.g., small leaf, spurless, yellow flower), three Chinese species of the genus Epimedium (Berberidaceae), E. ecalcaratum, E. platypetalum, and E. campanulatum, are controversial based on morphological characteristics. In the present study, the descriptions of morphological characteristics for the three species were revised based on extensive studies and observations both in field and in herbaria. In general, E. ecalcaratum has long creeping rhizomes 1–3 mm in diameter, two alternate or opposite trifoliolate leaves, 7–14 flowers, and petals obovate and apex subacute. Epimedium platypetalum has short or long-creeping rhizomes 1–3 mm in diameter, one trifoliolate leaf, 2–6 flowers, and petals oblong and apex rounded. Epimedium campanulatum has compact rhizomes 4–6 mm in diameter, two alternate or opposite trifoliolate leaves, 15–43 flowers, and petals obovate and apex rounded. Through comparison, we found that despite the close affinity of these three species, they can be distinguished by rhizome differences, stem-leaves, the morphology of flower (e.g., petals), and the number of per inflorenscence

Improved Genetic Algorithm for Solving Green Path Models of Concrete Trucks

In this paper, for the problem of high total fuel consumption of distribution trucks when multiple concrete-mixing plants distribute concrete together, we established a green fuel consumption model for distribution trucks and solved the model with an improved genetic algorithm to obtain a green distribution scheme for trucks. Firstly, the fuel consumption model is established for the characteristics of commercial concrete tankers; secondly, the adaptive elite retention strategy, adaptive crossover, mutation operator, and immune operation are added to the genetic algorithm to improve it; and finally, the model is solved to obtain the green distribution scheme. The total fuel consumption in this experiment was 189.6 L when the green distribution scheme was used; compared to the total fuel consumption under the original scheme (240 L), the total fuel consumption was reduced by 21.25%. The experimental results show that the total fuel consumption of delivery trucks can be significantly reduced based on the established green fuel consumption model, and the improved genetic algorithm can effectively solve the model

IL-2 family of cytokines in T regulatory cell development and homeostasis

Interleukin 2 (IL-2) induces an essential signal for T regulatory (Treg) cells. Without a functional IL-2R, only immature CD4(+) Foxp3(low) CD25(neg) T cells develop, and these cells fail to suppress autoreactive T cells in the periphery. IL-2 functions during Treg cell development by upregulating Foxp3 and CD25 and by increasing the number of thymic Treg cells. Upon exiting the thymus during neonatal life, IL-2 is responsible for rapid amplification of the number of Treg cells in peripheral lymph nodes to insure suppression of autoreactive T cells that escape negative selection, thereby maintaining tolerance. The homeostasis of Treg cells in mature immunocompetent mice also depends on IL-2. However, there is an alternative mechanism for Treg cells homeostasis that may represent a minor IL-2-independent pathway or the consequence of weak and very transient IL-2R signaling. Thus, IL-2 provides importance signals for Treg cell development and for their homeostasis in peripheral immune tissues

A topical aqueous oxygen emulsion stimulates granulation tissue formation in a porcine second-degree burn wound

Oxygen is an essential substance for wound healing. Limited studies have shown that topical oxygen can influence healing. This study evaluated the effects of a Topical Oxygen Emulsion (TOE) on burn wound healing. A porcine second-degree burn wound model was used in the study. Burn wounds were randomly assigned to TOE, vehicle control, and no-treatment (air) groups. Effects of TOE on the granulation tissue formation and angiogenesis were studied using hematoxylin and eosin histological analysis. Protein production and gene expression of types I and III collagen and vascular endothelial growth factor (VEGF) were determined using immunofluorescent staining and Reverse Transcription and Polymerase Chain Reaction (RT-PCR), respectively. The TOE treated wounds exhibited better angiogenesis and granulation tissue formation by histology examination. The immunofluorescence staining and RT-PCR analysis demonstrated that protein production and mRNA expression of VEGF and collagen III were significantly higher in TOE treatment group than vehicle alone and air control groups, while there was no significant difference in the level of collagen I. Our data demonstrate that TOE enhances burn wound healing via stimulating the expression of VEGF and type III collagen and strongly indicates the potential use of TOE in wounds

Effect of the 1,450 nm diode non-ablative laser on collagen expression in an artificial skin model

The 1,450-nm Smoothbeam Laser is a diode laser equipped with a cryogen cooling spray. Primary objectives were to evaluate the effects of this non-ablative laser on Apligraf (bioengineered skin-substitute) and to document its use as a model for non-ablative procedures. We also measured the effects of laser fluence levels on collagen and elastin expression. Three sheets of Apligraf were used for this study. Each received six separate laser applications at 4J, 6J, 8J, 10 J, 12J, and 14J. The sheets were then incubated with 10% CO(2) at 37 degrees C and samples were collected and analyzed 3 days later, using RT-PCR and immunofluorescent staining. Collagen III expressions significantly increased in both mRNA and protein levels at approximately 12 J. There appears to be a threshold effect where there is very little increased collagen III mRNA and protein expression until the laser fluence reaches around 12J