Galectin-3 promotes noncanonical inflammasome activation through intracellular binding to lipopolysaccharide glycans.

Cytosolic lipopolysaccharides (LPSs) bind directly to caspase-4/5/11 through their lipid A moiety, inducing inflammatory caspase oligomerization and activation, which is identified as the noncanonical inflammasome pathway. Galectins, ß-galactoside-binding proteins, bind to various gram-negative bacterial LPS, which display ß-galactoside-containing polysaccharide chains. Galectins are mainly present intracellularly, but their interactions with cytosolic microbial glycans have not been investigated. We report that in cell-free systems, galectin-3 augments the LPS-induced assembly of caspase-4/11 oligomers, leading to increased caspase-4/11 activation. Its carboxyl-terminal carbohydrate-recognition domain is essential for this effect, and its N-terminal domain, which contributes to the self-association property of the protein, is also critical, suggesting that this promoting effect is dependent on the functional multivalency of galectin-3. Moreover, galectin-3 enhances intracellular LPS-induced caspase-4/11 oligomerization and activation, as well as gasdermin D cleavage in human embryonic kidney (HEK) 293T cells, and it additionally promotes interleukin-1ß production and pyroptotic death in macrophages. Galectin-3 also promotes caspase-11 activation and gasdermin D cleavage in macrophages treated with outer membrane vesicles, which are known to be taken up by cells and release LPSs into the cytosol. Coimmunoprecipitation confirmed that galectin-3 associates with caspase-11 after intracellular delivery of LPSs. Immunofluorescence staining revealed colocalization of LPSs, galectin-3, and caspase-11 independent of host N-glycans. Thus, we conclude that galectin-3 amplifies caspase-4/11 oligomerization and activation through LPS glycan binding, resulting in more intense pyroptosis-a critical mechanism of host resistance against bacterial infection that may provide opportunities for new therapeutic interventions.

The histone deacetylases Rpd3 and Hst1 antagonistically regulate de novo NAD+ metabolism in the budding yeast Saccharomyces cerevisiae.

NAD+ is a cellular redox cofactor involved in many essential processes. The regulation of NAD+ metabolism and the signaling networks reciprocally interacting with NAD+-producing metabolic pathways are not yet fully understood. The NAD+-dependent histone deacetylase (HDAC) Hst1 has been shown to inhibit de novo NAD+ synthesis by repressing biosynthesis of nicotinic acid (BNA) gene expression. Here, we alternatively identify HDAC Rpd3 as a positive regulator of de novo NAD+ metabolism in the budding yeast Saccharomyces cerevisiae. We reveal that deletion of RPD3 causes marked decreases in the production of de novo pathway metabolites, in direct contrast to deletion of HST1. We determined the BNA expression profiles of rpd3Δ and hst1Δ cells to be similarly opposed, suggesting the two HDACs may regulate the BNA genes in an antagonistic fashion. Our chromatin immunoprecipitation analysis revealed that Rpd3 and Hst1 mutually influence each other's binding distribution at the BNA2 promoter. We demonstrate Hst1 to be the main deacetylase active at the BNA2 promoter, with hst1Δ cells displaying increased acetylation of the N-terminal tail lysine residues of histone H4, H4K5, and H4K12. Conversely, we show that deletion of RPD3 reduces the acetylation of these residues in an Hst1-dependent manner. This suggests that Rpd3 may function to oppose spreading of Hst1-dependent heterochromatin and represents a unique form of antagonism between HDACs in regulating gene expression. Moreover, we found that Rpd3 and Hst1 also coregulate additional targets involved in other branches of NAD+ metabolism. These findings help elucidate the complex interconnections involved in effecting the regulation of NAD+ metabolism.

The Histone Deacetylases Hst1 and Rpd3 Integrate De Novo NAD+ Metabolism with Phosphate Sensing in Saccharomyces cerevisiae.

Nicotinamide adenine dinucleotide (NAD+) is a critical cofactor essential for various cellular processes. Abnormalities in NAD+ metabolism have also been associated with a number of metabolic disorders. The regulation and interconnection of NAD+ metabolic pathways are not yet completely understood. By employing an NAD+ intermediate-specific genetic system established in the model organism S. cerevisiae, we show that histone deacetylases (HDACs) Hst1 and Rpd3 link the regulation of the de novo NAD+ metabolism-mediating BNA genes with certain aspects of the phosphate (Pi)-sensing PHO pathway. Our genetic and gene expression studies suggest that the Bas1-Pho2 and Pho2-Pho4 transcription activator complexes play a role in this co-regulation. Our results suggest a model in which competition for Pho2 usage between the BNA-activating Bas1-Pho2 complex and the PHO-activating Pho2-Pho4 complex helps balance de novo activity with PHO activity in response to NAD+ or phosphate depletion. Interestingly, both the Bas1-Pho2 and Pho2-Pho4 complexes appear to also regulate the expression of the salvage-mediating PNC1 gene negatively. These results suggest a mechanism for the inverse regulation between the NAD+ salvage pathways and the de novo pathway observed in our genetic models. Our findings help provide a molecular basis for the complex interplay of two different aspects of cellular metabolism.

Galectin-12 enhances inflammation by promoting M1 polarization of macrophages and reduces insulin sensitivity in adipocytes.

Galectin-12 is a member of an animal lectin family with affinity for ß-galactosides and containing consensus amino acid sequences. Here, we found that galectin-12 was expressed in macrophages and thus aimed to determine how galectin-12 affects inflammation and macrophage polarization and activation. The ablation of galectin-12 did not affect bone marrow cells to differentiate into macrophages, but reduced phagocytic activity against Escherichia coli and lowered the secretion of nitric oxide. The ablation of galectin-12 also resulted in the polarization of macrophages into the M2 direction, as indicated by increases in the levels of M2 markers, namely, resistin-like ß (FIZZ1) and chitinase 3-like 3 (Ym1), as well as a reduction in the expression levels of a number of M1 pro-inflammatory cytokines. We found that the diminished expression of pro-inflammatory cytokines in macrophages resulting from galectin-12 deletion was due to reduced activation of IKKα/ß, Akt and ERK, which in turn caused decreased activation of NF-κB and activator protein 1. The activation of STAT3 was much higher in Gal12(-/-) macrophages activated by lipopolysaccharide, which was correlated with higher levels of IL-10. Adipocytes showed higher insulin sensitivity when treated with Gal12(-/-) macrophage-conditioned media than those treated with Gal12(+/+) macrophages. We conclude galectin-12 negatively regulates macrophage polarization into the M2 population, resulting in enhanced inflammatory responses and also in turn causing decreased insulin sensitivity in adipocytes. This has implications in the treatment of a wide spectrum of metabolic disorders.

Effect of microRNA-155 on the interferon-gamma signaling pathway in biliary atresia.

MicroRNAs (miRNAs) are ~22-nucleotide long RNAs that negatively regulate gene expression and inflammatory responses in eukaryotes. The aim of this work was to evaluate the roles of miRNA (miR)-155 on the interferon-γ (IFN-γ)-induced response in biliary atresia (BA), which is the most common form of pediatric chronic liver disease and a leading indication for pediatric liver transplantation. The expression of miR-155 and the suppressor of cytokine signaling 1 (SOCS1) gene in human and mice liver tissues of BA and healthy controls was evaluated. IFN-γ-induced expression of miR-155, inflammatory cytokines and chemokines was determined in bile duct cells. A miR-155 inhibitor was used to determine the influence in the IFN-γ-induced signaling pathway by western blot analysis. A strong up-regulation of miR-155 expression was observed in BA histologic sections and mouse bile duct cells treated with IFN-γ. miR-155 down-regulated SOCS1 protein expression by targeting its mRNA. Up-regulation of miR-155 expression by IFN-γ in bile duct cells led to the activation of signal transducers and activators of transcription 1 (Stat1) and inflammatory cytokines through the Janus kinase (Jak)/Stat pathway, whereas targeted inhibition of miR-155 expression by anti-miRNA oligonucleotides significantly decreased the mRNA or protein expression levels of these inflammatory cytokines and Stat1. Overall, our results suggest that miR-155 regulates the IFN-γ signaling pathway by targeting SOCS1 expression and may be a potential target in BA therapy.

Cross-Species, Amplifiable EST-SSR Markers for Amentotaxus Species Obtained by Next-Generation Sequencing.

Amentotaxus, a genus of Taxaceae, is an ancient lineage with six relic and endangered species. Four Amentotaxus species, namely A. argotaenia, A. formosana, A. yunnanensis, and A. poilanei, are considered a species complex because of their morphological similarities. Small populations of these species are allopatrically distributed in Asian forests. However, only a few codominant markers have been developed and applied to study population genetic structure of these endangered species. In this study, we developed and characterized polymorphic expressed sequence tag-simple sequence repeats (EST-SSRs) from the transcriptome of A. formosana. We identified 4955 putative EST-SSRs from 68,281 unigenes as potential molecular markers. Twenty-six EST-SSRs were selected for estimating polymorphism and transferability among Amentotaxus species, of which 23 EST-SSRs were polymorphic within Amentotaxus species. Among these, the number of alleles ranged from 1-4, the polymorphism information content ranged from 0.000-0.692, and the observed and expected heterozygosity were 0.000-1.000 and 0.080-0.740, respectively. Population genetic structure analyses confirmed that A. argotaenia and A. formosana were separate species and A. yunnanensis and A. poilanei were the same species. These novel EST-SSRs can facilitate further population genetic structure research of Amentotaxus species.

Complete chloroplast genome of Angelica hirsutiflora Liu et al. 1961 (Apiaceae).

Angelica hirsutiflora Liu et al.1961, is a perennial herb in the Apiaceae family that is endemic to Taiwan. In this study, the complete circular chloroplast genome of A. hirsutiflora was reconstructed and annotated using Illumina sequencing. The size of the chloroplast genome is 154,266 bp, consisting of two inverted repeats (IRs, 25,075 bp) separated by a large single-copy region (LSC, 86,569 bp) and a small single-copy region (SSC, 17,547 bp). The GC content of the chloroplast genome is 37.6%. There are 114 different genes in the chloroplast genome of A. hirsutiflora, including 80 protein-coding genes, 30 tRNA genes and four rRNA genes. A maximum-likelihood phylogenetic analysis showed that A. hirsutiflora forms a distinct clade, and separated from other species within the genus Angelica. This study provided insights into the evolutionary relationships among different species of Angelica.

A taxonomic revision of the genus Angelica (Apiaceae) in Taiwan with a new species A. aliensis.

BACKGROUND: Angelica L. sensu lato is a taxonomically complex genus, and many studies have utilized morphological and molecular features to resolve its classification issues. In Taiwan, there are six taxa within Angelica, and their taxonomic treatments have been a subject of controversy. In this study, we conducted a comprehensive analysis incorporating morphological and molecular (cpDNA and nrDNA) characteristics to revise the taxonomic treatments of Angelica in Taiwan. RESULTS: As a result of our research, we have revised the classification between A. dahurica var. formosana and A. pubescens and merged two varieties of A. morrisonicola into a single taxon. A new taxon, A. aliensis, has been identified and found to share a close relationship with A. tarokoensis. Based on the morphological and molecular characteristics data, it has been determined that the former three taxa should be grouped into the Eurasian Angelica clade, while the remaining four taxa should belong to the littoral Angelica clade. Furthermore, Angelica species in Taiwan distributed at higher altitudes displayed higher genetic diversity, implying that the central mountain range of Taiwan serves as a significant reservoir of plant biodiversity. Genetic drift, such as bottlenecks, has been identified as a potential factor leading to the fixation or reduction of genetic diversity of populations in most Angelica species. We provide key to taxa, synopsis, phenology, and distribution for each taxon of Taiwan. CONCLUSIONS: Our comprehensive analysis of morphological and molecular features has shed light on the taxonomic complexities within Angelica in Taiwan, resolving taxonomic issues and providing valuable insights into the phylogenetic relationships of Angelica in Taiwan.

Footprints of natural and artificial selection for photoperiod pathway genes in Oryza.

Asian rice, Oryza sativa, consists of two major subspecies, indica and japonica, which are physiologically differentiated and adapted to different latitudes. Genes for photoperiod sensitivity are likely targets of selection along latitude. We examined the footprints of natural and artificial selections for four major genes of the photoperiod pathway, namely PHYTOCHROME B (PhyB), HEADING DATE 1 (Hd1), HEADING DATE 3a (Hd3a), and EARLY HEADING DATE 1 (Ehd1), by investigation of the patterns of nucleotide polymorphisms in cultivated and wild rice. Geographical subdivision between tropical and subtropical O. rufipogon was found for all of the photoperiod genes in plants divided by the Tropic of Cancer (TOC). All of these genes, except for PhyB, were characterized by the existence of clades that split a long time ago and that corresponded to latitudinal subdivisions, and revealed a likely diversifying selection. Ssp. indica showed close affinity to tropical O. rufipogon for all genes, while ssp. japonica, which has a much wider range of distribution, displayed complex patterns of differentiation from O. rufipogon, which reflected various agricultural needs in relation to crop yield. In japonica, all genes, except Hd3a, were genetically differentiated at the TOC, while geographical subdivision occurred at 31°N in Hd3a, probably the result of varying photoperiods. Many other features of the photoperiod genes revealed domestication signatures, which included high linkage disequilibrium (LD) within genes, the occurrence of frequent and recurrent non-functional Hd1 mutants in cultivated rice, crossovers between subtropical and tropical alleles of Hd1, and significant LD between Hd1 and Hd3a in japonica and indica.

Effect of geographic isolation on genetic variation and population structure of Euphrasia nankotaizanensis, a threatened endemic alpine herb in Taiwan.

Euphrasia nankotaizanensis (Orobanchaceae) is a rare alpine herb that is endemic to Taiwan. Only four small populations remain in Xue, Nanhu, and Cilai Mountains of Taiwan. The distribution of alpine herbs is severely threatened by climate change, which influences genetic variation and population structure. In this study, we investigated the effects of the natural isolation of alpine habitats on the genetic diversity and geographic structure of populations of E. nankotaizanensis using chloroplast (cp) and nuclear DNA (nrDNA) markers. We found lower levels of genetic diversity in E. nankotaizanensis than in other alpine plants and little to no genetic variation within populations, which could be mainly attributed to the small population size and genetic drift. Only one nrDNA haplotype was present in each population. The lack of monophyly of the four populations in cpDNA probably resulted from lineage sorting or occasional long-distance seed dispersal. Phylogeographic analysis suggested that Nanhu Mountain was probably a refugium over the glacial maxima, agreeing with the potential refugia in central Taiwan. The STRUCTURE and AMOVA analyses revealed significant genetic differentiation in nrDNA among the mountains, which resulted from geographical isolation among these mountains. Estimates of the effective population size (Ne) and demography reflected lower Ne values and a recent population decline, probably implying a greater extinction risk for E. nankotaizanensis. We observed genetic depletion and considerable genetic differentiation among mountain populations, which should be considered in future conservation efforts for this species. In addition, this study provides important insights into the long-term potential of alpine herbs in Taiwan, which are useful for a better prediction of their responses to future climate change.

Complete chloroplast genome and phylogenetic analysis of Bupleurum kaoi Liu, Chao, and Chuang, 1977: an endemic species in Taiwan.

Bupleurum kaoi Liu, Chao, and Chuang is an endemic and endangered herb in Taiwan. In this study, the complete circular chloroplast genome of B. kaoi was reconstructed and annotated using Illumina sequencing. The genome size of B. kaoi is 155,938 bp, including a pair of inverted repeat regions (IRs: 26308 bp), separated by a large single-copy (LSC) region of 85,784 bp and a small single-copy (SSC) region of 17,538 bp. The GC content of the chloroplast genome is 37.6%. There are 113 different genes in the chloroplast genome of B. kaoi, including 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. A maximum-likelihood phylogenetic analysis showed that Bupleurum species is the monophyletic group, and B. kaoi belongs to subgenus Bupleurum and is closely related to B. scorzonerifolium.

Complete mitogenome of Antheraea formosana Sonan, 1937 (Lepidoptera: Saturniidae): an endemic silkmoth in Taiwan.

The complete mitogenome of an endemic silkmoth in Taiwan, Antheraea formosana, was determined using Illumina next-generation sequencing. The mitogenome is 15,318 bp in length and consists of 13 protein-coding genes (PCGs), two rRNAs, 22 tRNAs, and one non-coding control region. The overall base composition of the mitogenome showed a high A + T bias, and the A + T content (80.2%) was significantly higher than the G + C content (19.8%). All PCGs use the typical ATN as the initiation codon, with the exception of cox2, which begins with GTG, respectively. The complete mitogenome was used to reconstruct a phylogenetic tree, indicating that A. formosana is more closely related to Antheraea assamensis than other Antheraea species, with 93.19% nucleotide similarity.

Genetic population structure of the alpine species Rhododendron pseudochrysanthum sensu lato (Ericaceae) inferred from chloroplast and nuclear DNA.

BACKGROUND: A complex of incipient species with different degrees of morphological or ecological differentiation provides an ideal model for studying species divergence. We examined the phylogeography and the evolutionary history of the Rhododendron pseudochrysanthum s. l. RESULTS: Systematic inconsistency was detected between gene genealogies of the cpDNA and nrDNA. Rooted at R. hyperythrum and R. formosana, both trees lacked reciprocal monophyly for all members of the complex. For R. pseudochrysanthum s.l., the spatial distribution of the cpDNA had a noteworthy pattern showing high genetic differentiation (FST=0.56-0.72) between populations in the Yushan Mountain Range and populations of the other mountain ranges. CONCLUSION: Both incomplete lineage sorting and interspecific hybridization/introgression may have contributed to the lack of monophyly among R. hyperythrum, R. formosana and R. pseudochrysanthum s.l. Independent colonizations, plus low capabilities of seed dispersal in current environments, may have resulted in the genetic differentiation between populations of different mountain ranges. At the population level, the populations of Central, and Sheishan Mountains may have undergone postglacial demographic expansion, while populations of the Yushan Mountain Range are likely to have remained stable ever since the colonization. In contrast, the single population of the Alishan Mountain Range with a fixed cpDNA haplotype may have experienced bottleneck/founder's events.

Conservation genetics and phylogeography of endangered and endemic shrub Tetraena mongolica (Zygophyllaceae) in Inner Mongolia, China.

BACKGROUND: Tetraena mongolica (Zygophyllaceae), an endangered endemic species in western Inner Mongolia, China. For endemic species with a limited geographical range and declining populations, historical patterns of demography and hierarchical genetic structure are important for determining population structure, and also provide information for developing effective and sustainable management plans. In this study, we assess genetic variation, population structure, and phylogeography of T. mongolica from eight populations. Furthermore, we evaluate the conservation and management units to provide the information for conservation. RESULTS: Sequence variation and spatial apportionment of the atpB-rbcL noncoding spacer region of the chloroplast DNA were used to reconstruct the phylogeography of T. mongolica. A total of 880 bp was sequenced from eight extant populations throughout the whole range of its distribution. At the cpDNA locus, high levels of genetic differentiation among populations and low levels of genetic variation within populations were detected, indicating that most seed dispersal was restricted within populations. CONCLUSIONS: Demographic fluctuations, which led to random losses of genetic polymorphisms from populations, due to frequent flooding of the Yellow River and human disturbance were indicated by the analysis of BEAST skyline plot. Nested clade analysis revealed that restricted gene flow with isolation by distance plus occasional long distance dispersal is the main evolutionary factor affecting the phylogeography and population structure of T. mongolica. For setting a conservation management plan, each population of T. mongolica should be recognized as a conservation unit.

Development of 12 genic microsatellite loci for a biofuel grass, Miscanthus sinensis (Poaceae).

PREMISE OF THE STUDY: Miscanthus, a nonfood plant with high potential as a biofuel, has been used in Europe and the United States. The selection of a cultivar with high biomass, photosynthetic efficiency, and stress resistance from wild populations has become an important issue. New genic microsatellite markers will aid the assessment of genetic diversity for different strains. METHODS AND RESULTS: Twelve polymorphic microsatellite markers derived from the transcriptome of Miscanthus sinensis fo. glaber were identified and screened on 80 individuals of M. sinensis. The number of alleles per locus ranged from 6 to 12, and the mean expected heterozygosity was 0.75. Cross-taxa transferability revealed that all loci can be applied to all varieties of M. sinensis, as well as the closely related species M. floridulus. CONCLUSIONS: These new genic microsatellite markers are useful for characterizing different traits in breeding programs or to select genes useful for biofuel.

Shift of bacterial communities in heavy metal-contaminated agricultural land during a remediation process.

Anthropogenic activities accompanied by heavy metal waste threaten the environment. Heavy metal pollution alters the soil microbial community composition, and the microorganisms that adapt to this stress increase in abundance. The remediation process of contaminated soil not only reduces the concentration of heavy metals but also alters the bacterial communities. High-throughput 16S rDNA sequencing techniques were applied to understand the changes in soil microbial communities. Using the remediation approach of the soil mixing, the concentrations of heavy metals in the contaminated areas were diluted and the soil environment was changed. The change of soil environment as a disturbance contributed to the alteration of microbial diversity of the remediated areas. The pH and heavy metals (Cr, Cu, Ni, and Zn) were the most influential factors driving the changes in community structure. The bacterial community structure was significantly different among sample areas. The decrease of heavy metals in soil may be the important factors that changed the microbial composition. This study provides the better understanding of the changes in composition of microbial communities affected by the remediation process in heavy metal-contaminated soil.

Complete mitochondrial genome of Manispentadactylapentadactyla (Mammalia: Pholidota), an endemic subspecies of Chinese pangolin: mitogenome characterisation and phylogenetic implications.

The Chinese pangolin Manispentadactyla is critically endangered because of over-exploitation and illegal trafficking and includes three subspecies. However, the taxonomic status of the three subspecies of the Chinese pangolin has not been well resolved, which impedes regional conservation and illegal trade traces. In this study, the complete mitogenome sequence of M.p.pentadactyla, an endemic subspecies of the Chinese pangolin in Taiwan, was determined. The complete mitogenome of M.p.pentadactyla is 16,570 base pairs (bp) in length with 13 protein-coding genes (PCG), 23 transfer RNAs (tRNAs), two ribosomal RNAs and a 1164 bp control region. The overall base composition of the genome showed a slight A + T bias (59.9%), positive AT skew (0.1515) and negative GC skew (-0.3406), which is similar to that of other pangolins. All PCGs started with a typical ATN codon and all tRNAs were typical cloverleaf-shaped secondary structures, except for tRNA-Ser(GCU). Phylogenetic analysis indicated a monophyletic relationship for M.p.pentadactyla and M.p.aurita and was monophyletic for M.p.pentadactyla, but paraphyletic for M.p.aurita. The paraphyly of M.p.aurita resulted from an incomplete lineage sorting. This study enriched the mitogenome database of the Chinese pangolin and the molecular information obtained should be very useful for future research on mitogenome evolution and genetic diversification in M.pentadactyla.

Galectin-8 Is Upregulated in Keratinocytes by IL-17A and Promotes Proliferation by Regulating Mitosis in Psoriasis.

Psoriasis is a chronic inflammatory skin disease that develops under the influence of the IL-23/T helper 17 cell axis and is characterized by intense inflammation and prominent epidermal hyperplasia. In this study, we demonstrate that galectin-8, a ß-galactoside‒binding lectin, is upregulated in the epidermis of human psoriatic skin lesions as well as in a mouse model of psoriasis induced by intradermal IL-23 injections and in IL-17A‒treated keratinocytes. We show that keratinocyte proliferation is less prominent in galectin-8‒knockout mice after intradermal IL-23 treatment than in wild-type mice. In addition, we show that galectin-8 levels in keratinocytes are positively correlated with the ability of the cells to proliferate and that transitioning from mitosis into G1 phase is delayed in galectin-8‒knockout HaCaT cells after cell-cycle synchronization and release. We demonstrate by immunofluorescence staining and immunoblotting the presence of galectin-8 within the mitotic apparatus. We reveal by coimmunoprecipitation and mass spectrometry analysis that α-tubulin interacts with galectin-8 during mitosis. Finally, we show that in the absence of galectin-8, pericentrin compactness is lessened and mitotic microtubule length is shortened, as demonstrated by immunofluorescence staining. We conclude that galectin-8 is upregulated in psoriasis and contributes to the hyperproliferation of keratinocytes by maintaining centrosome integrity during mitosis through interacting with α-tubulin.

Galectin-7 downregulation in lesional keratinocytes contributes to enhanced IL-17A signaling and skin pathology in psoriasis.

Psoriasis is a chronic inflammatory skin disease characterized by inflammatory cell infiltration, as well as hyperproliferation of keratinocytes in skin lesions, and is considered a metabolic syndrome. We found that the expression of galectin-7 is reduced in skin lesions of patients with psoriasis. IL-17A and TNF-α, 2 cytokines intimately involved in the development of psoriatic lesions, suppressed galectin-7 expression in human primary keratinocytes (HEKn cells) and the immortalized human keratinocyte cell line HaCaT. A galectin-7 knockdown in these cells elevated the production of IL-6 and IL-8 and enhanced ERK signaling when the cells were stimulated with IL-17A. Galectin-7 attenuated IL-17A-induced production of inflammatory mediators by keratinocytes via the microRNA-146a/ERK pathway. Moreover, galectin-7-deficient mice showed enhanced epidermal hyperplasia and skin inflammation in response to intradermal IL-23 injection. We identified fluvastatin as an inducer of galectin-7 expression by connectivity map analysis, confirmed this effect in keratinocytes, and demonstrated that fluvastatin attenuated IL-6 and IL-8 production induced by IL-17A. Thus, we validate a role of galectin-7 in the pathogenesis of psoriasis, in both epidermal hyperplasia and keratinocyte-mediated inflammatory responses, and formulate a rationale for the use of statins in the treatment of psoriasis.

Multilocus analysis of genetic divergence between outcrossing Arabidopsis species: evidence of genome-wide admixture.

• Outcrossing Arabidopsis species that diverged from their inbreeding relative Arabidopsis thaliana 5 million yr ago and display a biogeographical pattern of interspecific sympatry vs intraspecific allopatry provides an ideal model for studying impacts of gene introgression and polyploidization on species diversification. • Flow cytometry analyses detected ploidy polymorphisms of 2× and 4× in Arabidopsis lyrata ssp. kamchatica of Taiwan. Genomic divergence between species/subspecies was estimated based on 98 randomly chosen nuclear genes. Multilocus analyses revealed a mosaic genome in diploid A. l. kamchatica composed of Arabidopsis halleri-like and A. lyrata-like alleles. • Coalescent analyses suggest that the segregation of ancestral polymorphisms alone cannot explain the high inconsistency between gene trees across loci, and that gene introgression via diploid A. l. kamchatica likely distorts the molecular phylogenies of Arabidopsis species. However, not all genes migrated across species freely. Gene ontology analyses suggested that some nonmigrating genes were constrained by natural selection. • High levels of estimated ancestral polymorphisms between A. halleri and A. lyrata suggest that gene flow between these species has not completely ceased since their initial isolation. Polymorphism data of extant populations also imply recent gene flow between the species. Our study reveals that interspecific gene flow affects the genome evolution in Arabidopsis.