(1, 2), a line that had been used extensively in genetic analyses, with that of the unrelated standard inbred B73 (3) revealed unexpected differences between them. First, retrotransposon clusters, which make up the bulk of the maize genome (4-6), differed in composition and location relative to the genes in the region so that the two sequences could be aligned only at the genes they had in common. Second, and most strikingly, some genes present in McC were absent from B73, indicating that genetic colinearity was violated within the species. Noncolinear haplotypes were also found in a comparison of the genomic intervals containing the z1C zein gene cluster in B73 and BSSS53, inbred lines derived from the same synthetic population (7). The lengths of the z1C regions in the two inbreds varied by 50% because of differences in the number of zein and other genes and in the sizes of the retrotransposon clusters flanking them. Similar extensive nonhomologies were reported between the allelic regions of inbreds B73 and Mo17 at three additional chromosomal locations in the genome (8). That study established that more than one-third of the predicted genes were present in just one inbred at the loci examined, although many of the unshared genes appeared to be truncated. The observation that genes not shared between inbreds violate the maize-rice colinearity usually displayed by shared genes prompted the authors to speculate that unshared genes originated from insertions of a yet-unknown nature rather than deletions.High intraspecific haplotype variability is not restricted to maize, having been recently described in barley, another species with a large amount of repetitive DNA. A comparison of the Rph7 locus in two barley cultivars established that colinearity was restricted to Ͻ35% of the two sequences, principally because of differences in retrotransposon blocks (9). Interestingly, a gene encoding a truncated helicase was present in only one of the two cultivars. On the other hand, no cases of gene acquisition or loss were found in a comparison of two different orthologous regions between rice subspecies (10, 11). This finding suggests that the type of variation detected in maize and barley may not be a general feature of plant genomes. The functional significance of the ''plus-minus'' type of variation is also unclear, because the genes that vary among accessions of the same species are present in multiple copies (3), and many of them are clearly pseudogenes or gene fragments (8, 9). Independent of its generality or functional significance, the described variation raises an important question: How did it arise? Evidence presented here indicates that the apparent intraspecific violations of genetic colinearity in maize and, probably, barley, arise from the movement of genes or gene fragments by Helitrons, a recently discovered type of eukaryotic transposon (12).Helitrons were found by computational analysis of genomic sequences from Arabidopsis, rice, and Caenorhabditis elegans (12) and were later reported to be the caus...

IL‐33 is a novel cytokine of the IL‐1 family and mediates its biological effect via the receptor ST2, which is selectively expressed on Th2 cells but not Th1 cells. IL‐33 drives production of Th2‐associated cytokines including IL‐5 and IL‐13 and thereby promotes defense and pathology in mucosal organs. Cell locomotion is crucial to the induction of an effective immune response. We report here the chemoattraction of Th2 cells by IL‐33. Recombinant IL‐33 increased the proportion of human Th2 cells, but not Th1 cells, in polarized morphology in vitro and stimulated their subsequent invasion into collagen gels in an IL‐33 concentration‐dependent manner. Injection of recombinant IL‐33 into the footpad of ST2–/– mice which had been adoptively transferred with polarized Th2 cells, led to local accumulation of the transferred Th2 cells. These data therefore demonstrate that IL‐33 is a selective Th2 chemoattractant associated with the pro‐inflammatory property of this novel cytokine.

Galectin-3 is a β-galactoside-binding lectin that plays an important role in inflammatory diseases. It also interacts with the surface carbohydrates of many pathogens, including LPS. However, its role in infection is not fully understood. Data presented herein demonstrate for the first time that galectin-3 is a negative regulator of LPS-induced inflammation. Galectin-3 is constitutively produced by macrophages and directly binds to LPS. Galectin-3-deficient macrophages had markedly elevated LPS-induced signaling and inflammatory cytokine production compared with wild-type cells, which was specifically inhibited by the addition of recombinant galectin-3 protein. In contrast, blocking galectin-3 binding sites by using a neutralizing Ab or its ligand, β-lactose, enhanced LPS-induced inflammatory cytokine expression by wild-type macrophages. In vivo, mice lacking galectin-3 were more susceptible to LPS shock associated with excessive induction of inflammatory cytokines and NO production. However, these changes conferred greater resistance to Salmonella infection. Thus, galectin-3 is a previously unrecognized, naturally occurring, negative regulator of LPS function, which protects the host from endotoxin shock but, conversely, favors Salmonella survival.

The nuclear lamina is essential for the structural integration of the nuclear envelope. Nuclear envelope rupture and chromatin externalization is a hallmark of the formation of neutrophil extracellular traps (NETs). NET release was described as a cellular lysis process; however, this notion has been questioned recently. Here, we report that during NET formation, nuclear lamin B is not fragmented by destructive proteolysis, but rather disassembled into intact full-length molecules. Furthermore, we demonstrate that nuclear translocation of PKCa, which serves as the kinase to induce lamin B phosphorylation and disassembly, results in nuclear envelope rupture. Decreasing lamin B phosphorylation by PKCa inhibition, genetic deletion, or by mutating the PKCa consensus sites on lamin B attenuates extracellular trap formation. In addition, strengthening the nuclear envelope by lamin B overexpression attenuates NET release in vivo and reduces levels of NETassociated inflammatory cytokines in UVB-irradiated skin of lamin B transgenic mice. Our findings advance the mechanistic understanding of NET formation by showing that PKCa-mediated lamin B phosphorylation drives nuclear envelope rupture for chromatin release in neutrophils.

Rheumatoid arthritis pathogenesis comprises dysregulation in both innate and adaptive immunity. There is therefore intense interest in the factors that integrate these immunologic pathways in rheumatoid arthritis. In this paper, we report that IL-33, a novel member of the IL-1 family, can exacerbate anti–glucose-6-phosphate isomerase autoantibody-induced arthritis (AIA). Mice lacking ST2 (ST2−/−), the IL-33 receptor α-chain, developed attenuated AIA and reduced expression of articular proinflammatory cytokines. Conversely, treatment of wild-type mice with rIL-33 significantly exacerbated AIA and markedly enhanced proinflammatory cytokine production. However, IL-33 failed to increase the severity of the disease in mast cell-deficient or ST2−/− mice. Furthermore, mast cells from wild-type, but not ST2−/−, mice restored the ability of ST2−/− recipients to mount an IL-33–mediated exacerbation of AIA. IL-33 also enhanced autoantibody-mediated mast cell degranulation in vitro and in synovial tissue in vivo. Together these results demonstrate that IL-33 can enhance autoantibody-mediated articular inflammation via promoting mast cell degranulation and proinflammatory cytokine production. Because IL-33 is derived predominantly from synovial fibroblasts, this finding provides a novel mechanism whereby a host tissue-derived cytokine can regulate effector adaptive immune response via enhancing innate cellular activation in inflammatory arthritis.

It has long been known that probiotics can be used to maintain intestinal homeostasis and treat a number of gastrointestinal disorders, but the underlying mechanism has remained obscure. Recently, increasing evidence supports the notion that certain probiotic-derived components, such as bacteriocins, lipoteichoic acids, surface layer protein and secreted protein, have a similar protective role on intestinal barrier function as that of live probiotics. These bioactive components have been named ‘postbiotics’ in the most recent publications. We previously found that the Lactobacillus rhamnosus GG (LGG) culture supernatant is able to accelerate the maturation of neonatal intestinal defense and prevent neonatal rats from oral Escherichia coli K1 infection. However, the identity of the bioactive constituents has not yet been determined. In this study, using liquid chromatography-tandem mass spectrometry analysis, we identified a novel secreted protein (named HM0539 here) involved in the beneficial effect of LGG culture supernatant. HM0539 was recombinated, purified, and applied for exploring its potential bioactivity in vitro and in vivo. Our results showed that HM0539 exhibits a potent protective effect on the intestinal barrier, as reflected by enhancing intestinal mucin expression and preventing against lipopolysaccharide (LPS)- or tumor necrosis factor α (TNF-α)-induced intestinal barrier injury, including downregulation of intestinal mucin (MUC2), zonula occludens-1 (ZO-1) and disruption of the intestinal integrity. Using a neonatal rat model of E. coli K1 infection via the oral route, we verified that HM0539 is sufficient to promote development of neonatal intestinal defense and prevent against E. coli K1 pathogenesis. Moreover, we further extended the role of HM0539 and found it has potential to prevent dextran sulfate sodium (DSS)-induced colitis as well as LPS/D-galactosamine-induced bacterial translocation and liver injury. In conclusion, we identified a novel LGG postbiotic HM0539 which exerts a protective effect on intestinal barrier function. Our findings indicated that HM0539 has potential to become a useful agent for prevention and treatment of intestinal barrier dysfunction- related diseases.

SignificanceTornado-scale vortices in the intense tropical cyclone eyewall have been speculated upon for more than two decades, but their small horizontal scale, their fast movement, and the associated severe turbulence make them very difficult to observe directly, except for the case of Hurricane Hugo (1989) in the Atlantic basin. Using the Advanced Weather Research and Forecast large eddy simulation framework with the unprecedented horizontal grid size of 37 m, the numerical experiment in this study confirms the existence of simulated tornado-scale vortices similar to the Hugo case in the turbulent eyewall boundary layer and further suggests that tornado-scale vortices are prevalent at the inner edge of the intense eyewall convection.

The antitumor enzyme asparaginase, which targets essential amino acid L-asparagine and catalyzes it to L-aspartic acid and ammonia, has been used for years in the treatment of acute lymphoblastic leukemia (ALL), subtypes of myeloid leukemia and T-cell lymphomas, whereas the anti-chronic myeloid leukemia (CML) effect of asparaginase and its underlying mechanism has not been completely elucidated. We have shown here that asparaginase induced significant growth inhibition and apoptosis in K562 and KU812 cells. Apart from induction of apoptosis, we reported for the first time that asparaginase induced autophagic response in K562 and KU812 cells as evidenced by the formation of autophagosome, microtubule-associated protein light chain 3 (LC3)-positive autophagy-like vacuoles, and the upregulation of LC3-II. Further study suggested that the Akt/mTOR (mammalian target of rapamycin) and Erk (extracellular signal-regulated kinase) signaling pathway were involved in asparaginase-induced autophagy in K562 cells. Moreover, blocking autophagy using pharmacological inhibitors LY294002, chloroquine (CQ) and quinacrine (QN) enhanced asparaginase-induced cell death and apoptosis, indicating the cytoprotective role of autophagy in asparaginase-treated K562 and KU812 cells. Together, these findings provide a rationale that combination of asparaginase anticancer activity and autophagic inhibition might be a promising new therapeutic strategy for CML.