Cell surface RNAs control neutrophil recruitment.

RNAs localizing to the outer cell surface have been recently identified in mammalian cells, including RNAs with glycan modifications known as glycoRNAs. However, the functional significance of cell surface RNAs and their production are poorly known. We report that cell surface RNAs are critical for neutrophil recruitment and that the mammalian homologs of the sid-1 RNA transporter are required for glycoRNA expression. Cell surface RNAs can be readily detected in murine neutrophils, the elimination of which substantially impairs neutrophil recruitment to inflammatory sites in vivo and reduces neutrophils' adhesion to and migration through endothelial cells. Neutrophil glycoRNAs are predominantly on cell surface, important for neutrophil-endothelial interactions, and can be recognized by P-selectin (Selp). Knockdown of the murine Sidt genes abolishes neutrophil glycoRNAs and functionally mimics the loss of cell surface RNAs. Our data demonstrate the biological importance of cell surface glycoRNAs and highlight a noncanonical dimension of RNA-mediated cellular functions.

Inhaled SARS-CoV-2 vaccine for single-dose dry powder aerosol immunization.

The COVID-19 pandemic has fostered major advances in vaccination technologies1-4; however, there are urgent needs for vaccines that induce mucosal immune responses and for single-dose, non-invasive administration4-6. Here we develop an inhalable, single-dose, dry powder aerosol SARS-CoV-2 vaccine that induces potent systemic and mucosal immune responses. The vaccine encapsulates assembled nanoparticles comprising proteinaceous cholera toxin B subunits displaying the SARS-CoV-2 RBD antigen within microcapsules of optimal aerodynamic size, and this unique nano-micro coupled structure supports efficient alveoli delivery, sustained antigen release and antigen-presenting cell uptake, which are favourable features for the induction of immune responses. Moreover, this vaccine induces strong production of IgG and IgA, as well as a local T cell response, collectively conferring effective protection against SARS-CoV-2 in mice, hamsters and nonhuman primates. Finally, we also demonstrate a mosaic iteration of the vaccine that co-displays ancestral and Omicron antigens, extending the breadth of antibody response against co-circulating strains and transmission of the Omicron variant. These findings support the use of this inhaled vaccine as a promising multivalent platform for fighting COVID-19 and other respiratory infectious diseases.

Haplotype-resolved 3D chromatin architecture of the hybrid pig.

In diploid mammals, allele-specific three-dimensional (3D) genome architecture may lead to imbalanced gene expression. Through ultradeep in situ Hi-C sequencing of three representative somatic tissues (liver, skeletal muscle, and brain) from hybrid pigs generated by reciprocal crosses of phenotypically and physiologically divergent Berkshire and Tibetan pigs, we uncover extensive chromatin reorganization between homologous chromosomes across multiple scales. Haplotype-based interrogation of multi-omic data revealed the tissue dependence of 3D chromatin conformation, suggesting that parent-of-origin-specific conformation may drive gene imprinting. We quantify the effects of genetic variations and histone modifications on allelic differences of long-range promoter-enhancer contacts, which likely contribute to the phenotypic differences between the parental pig breeds. We also observe the fine structure of somatically paired homologous chromosomes in the pig genome, which has a functional implication genome-wide. This work illustrates how allele-specific chromatin architecture facilitates concomitant shifts in allele-biased gene expression, as well as the possible consequential phenotypic changes in mammals.

Construction of a prognostic model for lung adenocarcinoma based on m6A/m5C/m1A genes.

BACKGROUND: Developing a prognostic model for lung adenocarcinoma (LUAD) that utilizes m6A/m5C/m1A genes holds immense importance in providing precise prognosis predictions for individuals. METHODS: This study mined m6A/m5C/m1A-related differential genes in LUAD based on public databases, identified LUAD tumor subtypes based on these genes, and further built a risk prognostic model grounded in differential genes between subtypes. The immune status between high- and low-risk groups was investigated, and the distribution of feature genes in tumor immune cells was analyzed using single-cell analysis. Based on the expression levels of feature genes, a projection of chemotherapeutic and targeted drugs was made for individuals identified as high-risk. Ultimately, cell experiments were further verified. RESULTS: The 6-gene risk prognosis model based on differential genes between tumor subtypes had good predictive performance. Individuals classified as low-risk exhibited a higher (P < 0.05) abundance of infiltrating immune cells. Feature genes were mainly distributed in tumor immune cells like CD4+T cells, CD8+T cells, and regulatory T cells. Four drugs with relatively low IC50 values were found in the high-risk group: Elesclomol, Pyrimethamine, Saracatinib, and Temsirolimus. In addition, four drugs with significant positive correlation (P < 0.001) between IC50 values and feature gene expression were found, including Alectinib, Estramustine, Brigatinib, and Elesclomol. The low expression of key gene NTSR1 reduced the IC50 value of irinotecan. CONCLUSION: Based on the m6A/m5C/m1A-related genes in LUAD, LUAD patients were divided into 2 subtypes, and a m6A/m5C/m1A-related LUAD prognostic model was constructed to provide a reference for the prognosis prediction of LUAD.

A kinetic model for solving a combination optimization problem in ab-initio Cryo-EM 3D reconstruction.

Cryo-Electron Microscopy (cryo-EM) is a widely used and effective method for determining the three-dimensional (3D) structure of biological molecules. For ab-initio Cryo-EM 3D reconstruction using single particle analysis (SPA), estimating the projection direction of the projection image is a crucial step. However, the existing SPA methods based on common lines are sensitive to noise. The error in common line detection will lead to a poor estimation of the projection directions and thus may greatly affect the final reconstruction results. To improve the reconstruction results, multiple candidate common lines are estimated for each pair of projection images. The key problem then becomes a combination optimization problem of selecting consistent common lines from multiple candidates. To solve the problem efficiently, a physics-inspired method based on a kinetic model is proposed in this work. More specifically, hypothetical attractive forces between each pair of candidate common lines are used to calculate a hypothetical torque exerted on each projection image in the 3D reconstruction space, and the rotation under the hypothetical torque is used to optimize the projection direction estimation of the projection image. This way, the consistent common lines along with the projection directions can be found directly without enumeration of all the combinations of the multiple candidate common lines. Compared with the traditional methods, the proposed method is shown to be able to produce more accurate 3D reconstruction results from high noise projection images. Besides the practical value, the proposed method also serves as a good reference for solving similar combinatorial optimization problems.

YAP1 regulates thrombopoiesis by binding to MYH9 in immune thrombocytopenia.

Immune thrombocytopenia (ITP) is a complicated bleeding disease characterized by sharp platelet reduction. As a dominating element involved in ITP, megakaryocytes (MKs) are responsible for thrombopoiesis. However, the mechanism underlying the dysregulation of thrombopoiesis that occurs in ITP remains unidentified. In this study, we examined the role of yes-associated protein 1 (YAP1) in thrombopoiesis during ITP. We observed a reduced YAP1 expression with cytoskeletal actin misalignment in MKs from ITP patients. By using an experimental ITP mouse model, we showed that reduced YAP1 expression induced aberrant MK distribution, reduced the percentage of late MKs among total MKs, and caused submaximal platelet recovery. Mechanistically, YAP1 upregulation by binding of GATA binding protein 1 (GATA1) to its promoter promoted MK maturation. Phosphorylated YAP1 promoted cytoskeletal activation by binding of its WW2 domain to myosin heavy chain 9 (MYH9), facilitating thrombopoiesis. Targeting YAP1 by its activator XMU-MP-1 was sufficient to rescue cytoskeletal defects and thrombopoiesis dysregulation in YAP1+/- mice with ITP and patients. Taken together, these results demonstrate a crucial role for YAP1 in thrombopoiesis, providing a potential for the development of diagnostic markers and therapeutic options for ITP.

Molecular basis of A. thaliana KEOPS complex in biosynthesizing tRNA t6A.

In archaea and eukaryotes, the evolutionarily conserved KEOPS is composed of four core subunits-Kae1, Bud32, Cgi121 and Pcc1, and a fifth Gon7/Pcc2 that is found in fungi and metazoa. KEOPS cooperates with Sua5/YRDC to catalyze the biosynthesis of tRNA N6-threonylcarbamoyladenosine (t6A), an essential modification needed for fitness of cellular organisms. Biochemical and structural characterizations of KEOPSs from archaea, yeast and humans have determined a t6A-catalytic role for Kae1 and auxiliary roles for other subunits. However, the precise molecular workings of KEOPSs still remain poorly understood. Here, we investigated the biochemical functions of A. thaliana KEOPS and determined a cryo-EM structure of A. thaliana KEOPS dimer. We show that A. thaliana KEOPS is composed of KAE1, BUD32, CGI121 and PCC1, which adopts a conserved overall arrangement. PCC1 dimerization leads to a KEOPS dimer that is needed for an active t6A-catalytic KEOPS-tRNA assembly. BUD32 participates in direct binding of tRNA to KEOPS and modulates the t6A-catalytic activity of KEOPS via its C-terminal tail and ATP to ADP hydrolysis. CGI121 promotes the binding of tRNA to KEOPS and potentiates the t6A-catalytic activity of KEOPS. These data and findings provide insights into mechanistic understanding of KEOPS machineries.

Ocr-mediated suppression of BrxX unveils a phage counter-defense mechanism.

The burgeoning crisis of antibiotic resistance has directed attention to bacteriophages as natural antibacterial agents capable of circumventing bacterial defenses. Central to this are the bacterial defense mechanisms, such as the BREX system, which utilizes the methyltransferase BrxX to protect against phage infection. This study presents the first in vitro characterization of BrxX from Escherichia coli, revealing its substrate-specific recognition and catalytic activity. We demonstrate that BrxX exhibits nonspecific DNA binding but selectively methylates adenine within specific motifs. Kinetic analysis indicates a potential regulation of BrxX by the concentration of its co-substrate, S-adenosylmethionine, and suggests a role for other BREX components in modulating BrxX activity. Furthermore, we elucidate the molecular mechanism by which the T7 phage protein Ocr (Overcoming classical restriction) inhibits BrxX. Despite low sequence homology between BrxX from different bacterial species, Ocr effectively suppresses BrxX's enzymatic activity through high-affinity binding. Cryo-electron microscopy and biophysical analyses reveal that Ocr, a DNA mimic, forms a stable complex with BrxX, highlighting a conserved interaction interface across diverse BrxX variants. Our findings provide insights into the strategic counteraction by phages against bacterial defense systems and offer a foundational understanding of the complex interplay between phages and their bacterial hosts, with implications for the development of phage therapy to combat antibiotic resistance.

ZmEREB92 plays a negative role in seed germination by regulating ethylene signaling and starch mobilization in maize.

Rapid and uniform seed germination is required for modern cropping system. Thus, it is important to optimize germination performance through breeding strategies in maize, in which identification for key regulators is needed. Here, we characterized an AP2/ERF transcription factor, ZmEREB92, as a negative regulator of seed germination in maize. Enhanced germination in ereb92 mutants is contributed by elevated ethylene signaling and starch degradation. Consistently, an ethylene signaling gene ZmEIL7 and an α-amylase gene ZmAMYa2 are identified as direct targets repressed by ZmEREB92. OsERF74, the rice ortholog of ZmEREB92, shows conserved function in negatively regulating seed germination in rice. Importantly, this orthologous gene pair is likely experienced convergently selection during maize and rice domestication. Besides, mutation of ZmEREB92 and OsERF74 both lead to enhanced germination under cold condition, suggesting their regulation on seed germination might be coupled with temperature sensitivity. Collectively, our findings uncovered the ZmEREB92-mediated regulatory mechanism of seed germination in maize and provide breeding targets for maize and rice to optimize seed germination performance towards changing climates.

Transcriptomic congruence analysis for evaluating model organisms.

Model organisms are instrumental substitutes for human studies to expedite basic, translational, and clinical research. Despite their indispensable role in mechanistic investigation and drug development, molecular congruence of animal models to humans has long been questioned and debated. Little effort has been made for an objective quantification and mechanistic exploration of a model organism's resemblance to humans in terms of molecular response under disease or drug treatment. We hereby propose a framework, namely Congruence Analysis for Model Organisms (CAMO), for transcriptomic response analysis by developing threshold-free differential expression analysis, quantitative concordance/discordance scores incorporating data variabilities, pathway-centric downstream investigation, knowledge retrieval by text mining, and topological gene module detection for hypothesis generation. Instead of a genome-wide vague and dichotomous answer of "poorly" or "greatly" mimicking humans, CAMO assists researchers to numerically quantify congruence, to dissect true cross-species differences from unwanted biological or cohort variabilities, and to visually identify molecular mechanisms and pathway subnetworks that are best or least mimicked by model organisms, which altogether provides foundations for hypothesis generation and subsequent translational decisions.

High fried food consumption impacts anxiety and depression due to lipid metabolism disturbance and neuroinflammation.

Western dietary patterns have been unfavorably linked with mental health. However, the long-term effects of habitual fried food consumption on anxiety and depression and underlying mechanisms remain unclear. Our population-based study with 140,728 people revealed that frequent fried food consumption, especially fried potato consumption, is strongly associated with 12% and 7% higher risk of anxiety and depression, respectively. The associations were more pronounced among male and younger consumers. Consistently, long-term exposure to acrylamide, a representative food processing contaminant in fried products, exacerbates scototaxis and thigmotaxis, and further impairs exploration ability and sociality of adult zebrafish, showing anxiety- and depressive-like behaviors. Moreover, treatment with acrylamide significantly down-regulates the gene expression of tjp2a related to the permeability of blood-brain barrier. Multiomics analysis showed that chronic exposure to acrylamide induces cerebral lipid metabolism disturbance and neuroinflammation. PPAR signaling pathway mediates acrylamide-induced lipid metabolism disorder in the brain of zebrafish. Especially, chronic exposure to acrylamide dysregulates sphingolipid and phospholipid metabolism, which plays important roles in the development of anxiety and depression symptoms. In addition, acrylamide promotes lipid peroxidation and oxidation stress, which participate in cerebral neuroinflammation. Acrylamide dramatically increases the markers of lipid peroxidation, including (±)5-HETE, 11(S)-HETE, 5-oxoETE, and up-regulates the expression of proinflammatory lipid mediators such as (±)12-HETE and 14(S)-HDHA, indicating elevated cerebral inflammatory status after chronic exposure to acrylamide. Together, these results both epidemiologically and mechanistically provide strong evidence to unravel the mechanism of acrylamide-triggered anxiety and depression, and highlight the significance of reducing fried food consumption for mental health.

GDF11 evokes lung injury, inflammation, and fibrosis in mice through the ALK5-Smad2/3 signaling pathway.

Growth differentiation factor 11 (GDF11) belongs to the transforming growth factor-ß (TGF-ß) superfamily and participates in various pathophysiological processes. Initially, GDF11 was suggested to act as a rejuvenator by improving age-related phenotypes of the heart, brain, and skeletal muscle in aged mice. However, recent studies demonstrate that GDF11 also serves as an adverse risk factor for human frailty and diseases. However, the role of GDF11 in pulmonary fibrosis (PF) remains unclear. In this study, we explored the role and signaling mechanisms of GDF11 in PF. We discovered that GDF11 expression was markedly upregulated in fibrotic lung tissues of both humans and mice. Intratracheal administration of commercial recombinant GDF11 caused lung injury, inflammation, and fibrogenesis in mice. Furthermore, adenovirus-mediated secretory expression of mature GDF11 was exacerbated, whereas full-length GDF11 or the GDF11 propeptide (GDF111-298) alleviated bleomycin-induced PF in mice. In vitro experiments demonstrated that GDF11 suppressed the growth of alveolar and bronchial epithelial cells (A549 and BEAS-2B) and pulmonary microvascular endothelial cells (HPMVEC), promoted fibroblast activation, and induced epithelial/endothelial-mesenchymal transition (EMT/EndoMT). These effects corresponded to the phosphorylation of Smad2/3, and blocking ALK5-Smad2/3 signaling abolished the in vivo and in vitro effects of GDF11. In conclusion, our findings provide evidence that GDF11 acts as a potent injurious, pro-inflammatory, and pro-fibrotic factor in the lungs via the ALK5-Smad2/3 pathway.

Modulation of monocyte activity by hepatocellular MicroRNA delivery through HBsAg particles: Implications for pathobiology of chronic hepatitis B.

BACKGROUND AND AIMS: HBsAg serves as an important immune-modulatory factor in chronic hepatitis B. One aspect of such modulation may act through monocytes, which are the major Ag-presenting cells taking up HBsAg. There is evidence for the encapsulation of hepatocellular microRNAs (miRNAs) by HBsAg particles, while its pathobiological significance is unclear. Here, we characterized the miRNA profile in patients with chronic hepatitis B and probed their association with liver inflammation. APPROACHES AND RESULTS: We collected plasma from patients that are treatment-naive with chronic hepatitis B (n = 110) and quantified total/HBsAg-enveloped miRNAs by qRT-PCR and plasma cytokines by ELISA. The biological effects of HBsAg-delivered miRNAs in monocytes were evaluated using multiple approaches. The clinical significance of candidate miRNAs and cytokines was corroborated in patients with HBV-associated advanced liver diseases. The plasma miRNA profile showed 2 major clusters, one significantly associated with HBsAg titer and the other correlated with liver inflammation. Among HBsAg-carried miRNAs, miR-939 displayed the most significant correlation with IL-8. Mechanistically, miR-939 in subviral particles enters monocytes and significantly augments IL-8 production through the mitogen-activated protein kinase (MAPK) p38 signaling pathway. Finally, the findings that miR-939 positively correlated with IL-8 level and inflammation/fibrosis stage in the cohort of HBV-associated advanced liver diseases support its causative role in the progression of liver diseases. CONCLUSIONS: HBsAg particles carry hepatocellular miRNAs, including miR-939, which enter monocytes and alter their functional status, such as IL-8 secretion. Our findings demonstrate that the HBsAg-miR-939-IL-8 axis may play a crucial role in HBV-induced hepatic necro-inflammation and the progression of advanced liver diseases.

C-Reactive Protein: The Most Familiar Stranger.

C-reactive protein (CRP) is a highly conserved pentraxin with pattern recognition receptor-like activities. However, despite being used widely as a clinical marker of inflammation, the in vivo functions of CRP and its roles in health and disease remain largely unestablished. This is, to certain extent, due to the drastically different expression patterns of CRP in mice and rats, raising concerns about whether the functions of CRP are essential and conserved across species and how these model animals should be manipulated to examine the in vivo actions of human CRP. In this review, we discuss recent advances highlighting the essential and conserved functions of CRP across species, and propose that appropriately designed animal models can be used to understand the origin-, conformation-, and localization-dependent actions of human CRP in vivo. The improved model design will contribute to establishing the pathophysiological roles of CRP and facilitate the development of novel CRP-targeting strategies.

Hippocampal excitation-inhibition balance underlies the 5-HT2C receptor in modulating depressive behaviours.

The implication of 5-hydroxytryptamine 2C receptor (5-HT2CR) in depression is a topic of debate, and the underlying mechanisms remain largely unclear. We now elucidate hippocampal excitation-inhibition (E/I) balance underlies the regulatory effects of 5-HT2CR in depression. Molecular biological analyses showed that chronic mild stress (CMS) reduced the expression of 5-HT2CR in hippocampus. We revealed that inhibition of 5-HT2CR induced depressive-like behaviors, reduced GABA release and shifted the E/I balance towards excitation in CA3 pyramidal neurons by using behavioral analyses, microdialysis coupled with mass spectrum, and electrophysiological recording. Moreover, 5-HT2CR modulated neuronal nitric oxide synthase (nNOS)-carboxy-terminal PDZ ligand of nNOS (CAPON) interaction through influencing intracellular Ca2+ release, as determined by fiber photometry and coimmunoprecipitation. Notably, disruption of nNOS-CAPON by specific small molecule compound ZLc-002 or AAV-CMV-CAPON-125C-GFP, abolished 5-HT2CR inhibition-induced depressive-like behaviors, as well as the impairment in soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex assembly-mediated GABA vesicle release and a consequent E/I imbalance. Importantly, optogenetic inhibition of CA3 GABAergic neurons prevented the effects of AAV-CMV-CAPON-125C-GFP on depressive behaviors in the presence of 5-HT2CR antagonist. Conclusively, our findings disclose the regulatory role of 5-HT2CR in depressive-like behaviors and highlight the hippocampal nNOS-CAPON coupling-triggered E/I imbalance as a pivotal cellular event underpinning the behavioral consequences of 5-HT2CR inhibition.

Lactobacillus casei Cell Wall Extract and Production of Galactose-Deficient IgA1 in a Humanized IGHA1 Mouse Model.

BACKGROUND: IgA nephropathy is the most common primary glomerulonephritis worldwide, and there is emerging evidence linking galactose-deficient IgA1 (Gd-IgA1) to the pathogenesis of the disease. However, mouse models that can be used to study Gd-IgA1's origin of production, biochemical characteristics, and immune reactivity are lacking. METHODS: We generated a humanized IgA1 mouse model with transgenic expression of the human IGHA1 gene from the mouse chromosomal locus of IgA heavy chain. The IGHA1+/+ mice were crossed with complement factor H heterozygous mutant (FHW/R) to generate IGHA1+/+FHW/R mice. IGHA1+/+ mice were exposed to different levels of environmental pathogens in the first 4 months, as housed in either germ-free, specific pathogen-free, or conventional environments. In addition, wild-type C57BL/6J mice, IGHA1+/+ mice, and IGHA1+/+FHW/R mice were inoculated with Lactobacillus casei cell bacterial wall extract (LCWE) mixed with complete Freund's adjuvant (CFA) at two months of age to develop a mouse model of IgA nephropathy. RESULTS: Elevated levels of human IgA1 in blood circulation and mucosal sites were observed in IGHA1+/+ mice from exposure to pathogens. Compared to buffer-treated control mice, LCWE plus CFA-treated mice had moderately elevated levels of circulating human IgA1 (by one fold) and human IgA1 immune complexes (by two folds). Serum Gd-IgA1 levels increased fourfold following LCWE treatments. Analyses of the O-glycopeptides of the IgA1 hinge region confirmed hypo-galactosylation of IgA1, with the variety of the glycoforms matching those seen in clinical samples. Furthermore, LCWE induced persistent IgA1 and C3 deposition in the glomerular mesangial areas in association with mesangial expansion and hypercellularity, which are frequently observed in IgA nephropathy biopsies. The IGHA1+/+FHW/R mice stimulated with LCWE and CFA developed albuminuria and hematuria. CONCLUSIONS: We observed elevated plasma Gd-IgA1 levels with kidney deposition of IgA1 in the IGHA1+/+ mice following LCWE and CFA. In conjunction with factor H mutation, the mice exhibited severe glomerular alterations, associated with hematuria and albuminuria in resemblance of clinical IgA nephropathy.

CircSCNN1A inhibits the proliferation, migration and invasion of renal cell carcinoma cells by decreasing CLDN8 expression through miR-590-5p.

BACKGROUND: Increasing evidence suggests that circular RNA (circRNA) plays a regulatory role in the progression of renal cell carcinoma (RCC). However, the precise function and underlying mechanism of circSCNN1A in RCC progression still remain unclear. METHODS: The expression levels of circSCNN1A, microRNA-590-5p (miR-590-5p), claudin 8 (CLDN8), cyclin D1, matrix metalloprotein 2 (MMP2), MMP9, E-cadherin, N-cadherin and vimentin were detected by a quantitative real-time polymerase chain reaction and Western blotting analysis. Immunohistochemistry assay was performed to analyze the positive expression rate of CLDN8. Cell proliferation was investigated by cell colony formation, 5-Ethynyl-2'-deoxyuridine and DNA content quantitation assays. Cell migration and invasion were assessed by wound-healing and transwell invasion assays. Interactions among circSCNN1A, miR-590-5p and CLDN8 were identified by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA pull-down assay. Xenograft mouse model assay was conducted to verify the effect of circSCNN1A on tumor formation in vivo. RESULTS: CircSCNN1A and CLDN8 expression were significantly downregulated, while miR-590-5p was upregulated in both RCC tissues and cells. CircSCNN1A overexpression inhibited RCC cell proliferation, migration and invasion, accompanied by decreases of cyclin D1, MMP2, MMP9, N-cadherin and vimentin expression and an increase of E-cadherin expression. CircSCNN1A acted as a miR-590-5p sponge and regulated RCC cell processes by binding to miR-590-5p. CLDN8, a target gene of miR-590-5p, was involved in the regulation of the biological behaviors of RCC cells by miR-590-5p. In addition, circSCNN1A induced CLDN8 production by interacting with miR-590-5p. Further, circSCNN1A suppressed tumor formation in vivo. CONCLUSION: CircSCNN1A inhibited RCC cell proliferation, migration and invasion by regulating the miR-590-5p/CLDN8 pathway.

Dynamic changes of endothelial and stromal cilia are required for the maintenance of corneal homeostasis.

Primary cilia are distributed extensively within the corneal epithelium and endothelium. However, the presence of cilia in the corneal stroma and the dynamic changes and roles of endothelial and stromal cilia in corneal homeostasis remain largely unknown. Here, we present compelling evidence for the presence of primary cilia in the corneal stroma, both in vivo and in vitro. We also demonstrate dynamic changes of both endothelial and stromal cilia during corneal development. In addition, our data show that cryoinjury triggers dramatic cilium formation in the corneal endothelium and stroma. Furthermore, depletion of cilia in mutant mice lacking intraflagellar transport protein 88 compromises the corneal endothelial capacity to establish the effective tissue barrier, leading to an upregulation of α-smooth muscle actin within the corneal stroma in response to cryoinjury. These observations underscore the essential involvement of corneal endothelial and stromal cilia in maintaining corneal homeostasis and provide an innovative strategy for the treatment of corneal injuries and diseases.

Toll-Like Receptors Mediate Opposing Dendritic Cell Effects on Treg/Th17 Balance in Mice With Intracerebral Hemorrhage.

BACKGROUND: Dendritic cells (DCs) regulate the immune response associated with T lymphocytes, but their role in stroke remains unclear. In this study, we investigated the causal relationship between DCs and T-cell response in intracerebral hemorrhage (ICH) by focusing on TLRs (toll-like receptors) that may modulate the function of DCs. METHODS: We studied the effects of TLR4, TLR2, and TLR9 on DC-mediated T-cell response and the outcomes of ICH using male C57BL/6 and CD11c-DTx (diphtheria toxin) receptor mice. We administered specific agents intraperitoneally or orally and evaluated the results using flow cytometry, real-time polymerase chain reaction, Western blotting, immunofluorescence staining, histopathology, and behavioral tests. RESULTS: TLR4 and TLR2 activation induces DC maturation and reduces the ratio of regulatory T to T-helper 17 cells in the brain and periphery after ICH. When either of these receptors is activated, it can worsen neuroinflammation and exacerbate ICH outcomes. TLR9 also promotes DC maturation, stabilizing the number of DCs, particularly conventional DCs. TLR9 has the opposite effects on regulatory T/T-helper 17 balance, neuroinflammation, and ICH outcomes compared with TLR4 and TLR2. Upon stimulation, TLR4 and TLR9 may achieve these effects through the p38-MAPK (p38-mitogen-activated protein kinase)/MyD88 (myeloid differentiation primary response gene 88) and indoleamine 2,3-dioxygenase 1 (IDO1)/GCN2 (general control nonderepressible 2) signaling pathways, respectively. DCs act as intermediaries for TLR-mediated T-cell response. CONCLUSIONS: TLR-mediated opposing effects of DCs on T-cell response may provide novel strategies to treat ICH.

Host specificity of plant-associated bacteria is negatively associated with genome size and host abundance along a latitudinal gradient.

Host specialization plays a critical role in the ecology and evolution of plant-microbe symbiosis. Theory predicts that host specialization is associated with microbial genome streamlining and is influenced by the abundance of host species, both of which can vary across latitudes, leading to a latitudinal gradient in host specificity. Here, we quantified the host specificity and composition of plant-bacteria symbioses on leaves across 329 tree species spanning a latitudinal gradient. Our analysis revealed a predominance of host-specialized leaf bacteria. The degree of host specificity was negatively correlated with bacterial genome size and the local abundance of host plants. Additionally, we found an increased host specificity at lower latitudes, aligning with the high prevalence of small bacterial genomes and rare host species in the tropics. These findings underscore the importance of genome streamlining and host abundance in the evolution of host specificity in plant-associated bacteria along the latitudinal gradient.