IL-15 Superagonist Expands mCD8+ T,NK and NKT Cells after Burn Injury but Fails to Improve Outcome during Burn Wound Infection

Background

Severely burned patients are highly susceptible to opportunistic infections and sepsis, owing to the loss of the protective skin barrier and immunological dysfunction. Interleukin-15 (IL-15) belongs to the IL-2 family of common gamma chain cytokines and stimulates the proliferation and activation of T (specifically memory CD8), NK and NKT cells. It has been shown to preserve T cell function and improve survival during cecal ligation and puncture (CLP)-induced sepsis in mice. However, the therapeutic efficacy of IL-15 or IL-15 superagonist (SA) during infection after burn injury has not been evaluated. Moreover, very few, if any, studies have examined, in detail, the effect of burn injury and infection on the adaptive immune system. Thus, we examined the effect of burn and sepsis on adaptive immune cell populations and the effect of IL-15 SA treatment on the host response to infection.

Methods

Mice were subjected to a 35% total body surface area burn, followed by wound infection with Pseudomonas aeruginosa. In some experiments, IL-15 SA was administered after burn injury, but before infection. Leukocytes in spleen, liver and peritoneal cavity were characterized using flow cytometry. Bacterial clearance, organ injury and survival were also assessed.

Results

Burn wound infection led to a significant decline in total white blood cell and lymphocyte counts and induced organ injury and sepsis. Burn injury caused decline in CD4⁺ and CD8⁺ T cells in the spleen, which was worsened by infection. IL-15 treatment inhibited this decline and significantly increased cell numbers and activation, as determined by CD69 expression, of CD4⁺, CD8⁺, B, NK and NKT cells in the spleen and liver after burn injury. However, IL-15 SA treatment failed to prevent burn wound sepsis-induced loss of CD4⁺, CD8⁺, B, NK and NKT cells and failed to improve bacterial clearance and survival.

Conclusion

Cutaneous burn injury and infection cause significant adaptive immune dysfunction. IL-15 SA does not augment host resistance to burn wound sepsis in mice despite inducing proliferation and activation of lymphocyte subsets.     

Serum MicroRNA-4521 is a Potential Biomarker for Focal Cortical Dysplasia with Refractory Epilepsy

Early biomarker-based diagnosis of focal cortical dysplasia (FCD) represents a major clinical challenge. The aim of this study was to identify novel brain microRNAs (miRNAs) in patients with refractory epilepsy and FCD as potential biomarkers. We evaluated serum hsa-miR-4521 as a promising novel biomarker in patients with FCD. Tissue for microarray was obtained from nine patients with temporal lobe refractory epilepsy who underwent surgery to remove epileptic foci identified by cortical video electroencephalogram monitoring. Control tissue was collected from eight patients with hypertension who required emergency surgery to remove an intracranial hematoma. The Affymetrix^® GeneChip^® Command Console^® Software (Affymetrix miRNA 4.0) was used to compare miRNA expression in the cerebral cortex of experimental and control patients. Temporal cortex tissue and serum samples were taken from the same patients for verification of hsa-miR-4521 expression by real-time quantitative polymerase chain reaction (RT-qPCR). The experimental and control patients did not differ significantly in terms of age and gender. 19.4 % (148/764) of the total miRNAs were differentially expressed in experimental and control tissue, which is in agreement with the existing literature. We selected miRNA-4521 for further analysis; the fold-change in expression was 14.4707 and the q value was almost 0, which confirmed up-regulation. Significant up-regulation of hsa-miR-4521 was further validated by RT-qPCR. miRNA microarrays can efficiently and conveniently identify differentially expressed miRNAs in epilepsy brain tissue. This is the first study to identify differential expression of hsa-miR-4521 in brain tissue and serum of refractory epilepsy patients and suggests that serum hsa-miR-4521 may represent a potential diagnostic biomarker for FCD with refractory epilepsy.

     

表达空肠弯曲菌CfrA蛋白重组乳酸乳球菌的构建及其免疫效果北大核心CSCD

【目的】本试验将空肠弯曲菌肠菌素受体蛋白CfrA编码基因导入食品级乳酸乳球菌表达系统,然后将重组乳酸乳球菌口服免疫鸡,降低空肠弯曲菌在鸡肠道中的定殖。【方法】利用PCR分别扩增空肠弯曲菌cfrA全基因及其N端片段,插入食品级表达载体pNZ8149多克隆位点并转化乳酸乳球菌NZ3900,通过Western blot鉴定重组菌株CfrA蛋白表达情况,同时通过筛选nisin浓度、温度、时间等诱导条件优化重组蛋白表达水平;进而将重组乳酸乳球菌经口服免疫SPF鸡,免疫后分别测定乳酸乳球菌自鸡体内的排出情况、以及诱导CfrA血清抗体和粘膜抗体水平,最后将空肠弯曲菌口服攻毒免疫后的鸡,通过测定鸡泄殖腔棉拭子中空肠弯曲菌的数目来判定口服免疫效果。【结果】Western blot检测显示CfrA全基因及其N端片段均可在重组乳酸乳球菌胞内可溶性表达,不分泌,筛选的最佳诱导表达条件为nisin浓度25 ng/mL、温度37°C、时间1 h。口服乳酸乳球菌10 d内自鸡体完全排空;鸡口服免疫后可产生CfrA蛋白特异性的血清IgG和肠粘膜sIgA抗体;重组乳酸乳球菌口服免疫后空肠弯曲菌在鸡体内的增殖速度显著低于对照组。【结论】成功构建了重组CfrA蛋白的食品级乳酸乳球菌诱导表达系统;表达CfrA蛋白的重组乳酸乳球菌口服免疫鸡对空肠弯曲菌在鸡肠道的定殖具有一定的抑制作用,为研制重组乳酸菌口服家禽免疫制剂防治空肠弯曲菌奠定了基础。     

Cellular and molecular remodelling of a host cell for vertical transmission of bacterial symbionts

Various insects require intracellular bacteria that are restricted to specialized cells (bacteriocytes) and are transmitted vertically via the female ovary, but the transmission mechanisms are obscure. We hypothesized that, in the whitefly Bemisia tabaci, where intact bacteriocytes (and not isolated bacteria) are transferred to oocytes, the transmission mechanism would be evident as cellular and molecular differences between the nymph (pre-adult) and adult bacteriocytes. We demonstrate dramatic remodelling of bacteriocytes at the developmental transition from nymph to adulthood. This transition involves the loss of cell–cell adhesion, high division rates to constant cell size and onset of cell mobility, enabling the bacteriocytes to crawl to the ovaries. These changes are accompanied by cytoskeleton reorganization and changes in gene expression: genes functioning in cell–cell adhesion display reduced expression and genes involved in cell division, cell motility and endocytosis/exocytosis have elevated expression in adult bacteriocytes, relative to nymph bacteriocytes. This study demonstrates, for the first time, how developmentally orchestrated remodelling of gene expression and correlated changes in cell behaviour underpin the capacity of bacteriocytes to mediate the vertical transmission and persistence of the symbiotic bacteria on which the insect host depends.     

Taxonomy of Fissocantharis Pic (Coleoptera,Cantharidae) from Guangxi,China, with descriptions of six new species

A total of 17 species of Fissocantharis Pic is recorded from Guangxi, China. Six species are described new to science, Fissocantharis sinensomima sp. n., Fissocantharis sexcostata sp. n., Fissocantharis basilaris sp. n., Fissocantharis eschara sp. n., Fissocantharis latipalpa sp. n. and Fissocantharis biprojicientis sp. n., and two previously known species are redescribed, Fissocantharis gracilipes (Pic, 1927) and Fissocantharis sinensis (Wittmer, 1988). These species are presented with habitus of males, abdominal sternites VIII of females and genitalia of both sexes. Fissocantharis flavofacialis (Pic, 1926) is synonymized with Fissocantharis angusta (Fairmaire, 1900); both were originally described in the genus Podabrus Westwood. Additionally, a key and a checklist of all the species of Fissocantharis from Guangxi are provided.     

A new species of Themus (Themus) Motschulsky from Yunnan,China and a redescription of T. (T.) testaceicollis Wittmer, 1983 (Coleoptera,Cantharidae)

A new species is described, Themus (Themus) dimorphus sp. n. from Yunnan, China. Themus (Themus) testaceicollis Wittmer, 1983 is redescribed and compared with the new species. The two species are illustrated with habitus and genitalia of both sexes and abdominal sternites VIII of female.     

Use of Transposon Promoter-Probe Vectors in the Metabolic Engineering of the Obligate Methanotroph Methylomonas sp. Strain 16a for Enhanced C40 Carotenoid Synthesis

The recent expansion of genetic and genomic tools for metabolic engineering has accelerated the development of microorganisms for the industrial production of desired compounds. We have used transposable elements to identify chromosomal locations in the obligate methanotroph Methylomonas sp. strain 16a that support high-level expression of genes involved in the synthesis of the C₄₀ carotenoids canthaxanthin and astaxanthin. with three promoterless carotenoid transposons, five chromosomal locations—the fliCS, hsdM, ccp-3, cysH, and nirS regions—were identified. Total carotenoid synthesis increased 10- to 20-fold when the carotenoid gene clusters were inserted at these chromosomal locations compared to when the same carotenoid gene clusters were integrated at neutral locations under the control of the promoter for the gene conferring resistance to chloramphenicol. A chromosomal integration system based on sucrose lethality was used to make targeted gene deletions or site-specific integration of the carotenoid gene cluster into the Methylomonas genome without leaving genetic scars in the chromosome from the antibiotic resistance genes that are present on the integration vector. The genetic approaches described in this work demonstrate how metabolic engineering of microorganisms, including the less-studied environmental isolates, can be greatly enhanced by identifying integration sites within the chromosome of the host that permit optimal expression of the target genes.