Genomes of the Banyan Tree and Pollinator Wasp Provide Insights into Fig-Wasp Coevolution.

Banyan trees are distinguished by their extraordinary aerial roots. The Ficus genus includes species that have evolved a species-specific mutualism system with wasp pollinators. We sequenced genomes of the Chinese banyan tree, F. microcarpa, and a species lacking aerial roots, F. hispida, and one wasp genome coevolving with F. microcarpa, Eupristina verticillata. Comparative analysis of the two Ficus genomes revealed dynamic karyotype variation associated with adaptive evolution. Copy number expansion of auxin-related genes from duplications and elevated auxin production are associated with aerial root development in F. microcarpa. A male-specific AGAMOUS paralog, FhAG2, was identified as a candidate gene for sex determination in F. hispida. Population genomic analyses of Ficus species revealed genomic signatures of morphological and physiological coadaptation with their pollinators involving terpenoid- and benzenoid-derived compounds. These three genomes offer insights into and genomic resources for investigating the geneses of aerial roots, monoecy and dioecy, and codiversification in a symbiotic system.

A mouse model to distinguish NLRP6-mediated inflammasome-dependent and -independent functions.

The NOD-like receptor (NLR) family pyrin domain containing 6 (NLRP6) serves as a sensor for microbial dsRNA or lipoteichoic acid (LTA) in intestinal epithelial cells (IECs), and initiating multiple pathways including inflammasome pathway and type I interferon (IFN) pathway, or regulating nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. NLRP6 can exert its function in both inflammasome-dependent and inflammasome-independent manners. However, there is no tool to distinguish the contribution of individual NLRP6-mediated pathway to the physiology and pathology in vivo. Here, we validated that Arg39 and Trp50 residues in the pyrin domain (PYD) of murine NLRP6 are required for ASC recruitment and inflammasome activation, but are not important for the RNA binding and PYD-independent NLRP6 oligomerization. We further generated the Nlrp6R39E&W50E mutant mice, which showed reduced inflammasome activation in either steady state intestine or during viral infection. However, the type I IFN production in cells or intestine tissue from Nlrp6R39E&W50E mutant mice remain normal. Interestingly, NLRP6-mediated inflammasome activation or the IFN-I production seems to play distinct roles in the defense responses against different types of RNA viruses. Our work generated a useful tool to study the inflammasome-dependent role of NLRP6 in vivo, which might help to understand the complexity of multiple pathways mediated by NLRP6 in response to the complicated and dynamic environmental cues in the intestine.

The water lily genome and the early evolution of flowering plants.

Water lilies belong to the angiosperm order Nymphaeales. Amborellales, Nymphaeales and Austrobaileyales together form the so-called ANA-grade of angiosperms, which are extant representatives of lineages that diverged the earliest from the lineage leading to the extant mesangiosperms1-3. Here we report the 409-megabase genome sequence of the blue-petal water lily (Nymphaea colorata). Our phylogenomic analyses support Amborellales and Nymphaeales as successive sister lineages to all other extant angiosperms. The N. colorata genome and 19 other water lily transcriptomes reveal a Nymphaealean whole-genome duplication event, which is shared by Nymphaeaceae and possibly Cabombaceae. Among the genes retained from this whole-genome duplication are homologues of genes that regulate flowering transition and flower development. The broad expression of homologues of floral ABCE genes in N. colorata might support a similarly broadly active ancestral ABCE model of floral organ determination in early angiosperms. Water lilies have evolved attractive floral scents and colours, which are features shared with mesangiosperms, and we identified their putative biosynthetic genes in N. colorata. The chemical compounds and biosynthetic genes behind floral scents suggest that they have evolved in parallel to those in mesangiosperms. Because of its unique phylogenetic position, the N. colorata genome sheds light on the early evolution of angiosperms.

Thermo-Sensitive Spikelet Defects 1 acclimatizes rice spikelet initiation and development to high temperature.

Crop reproductive development is vulnerable to heat stress, and the genetic modulation of thermotolerance during the reproductive phase, especially the early stage, remains poorly understood. We isolated a Poaceae-specific FAR-RED ELONGATED HYPOCOTYLS3 (FHY3)/FAR-RED IMPAIRED RESPONSE1 (FAR1)family transcription factor, Thermo-sensitive Spikelet Defects 1 (TSD1), derived from transposase in rice (Oryza sativa) TSD1 was highly expressed in spikelets, induced by heat, and specifically enhanced the thermotolerance of spikelet morphogenesis. Disrupting TSD1 did not affect vegetative growth but markedly retarded spikelet initiation and development, as well as caused varying degrees of spikelet degeneration, depending on the temperature. Most tsd1 spikelets were normal at low temperature but gradually degenerated as temperature increased, and all disappeared at high temperature, leading to naked branches. TSD1 directly promoted the transcription of YABBY1 and YABBY3 and could physically interact with YABBY1 and three TOB proteins, YABBY5, YABBY4, and YABBY3. These YABBY proteins can form either homodimers or heterodimers and play an important role in spikelet morphogenesis, similar to TSD1. Notably, the knockout mutant yab5-ko and double mutant tsd1 yab5-ko resembled tsd1 in spikelet appearance and response to temperature, indicating that these genes likely participate in spikelet development through the cooperative TSD1-YABBY module. These findings reveal a distinctive function of FHY3/FAR1 family genes and a unique TSD1-YABBY complex to acclimate spikelet development to high temperature in rice, providing insight into the regulating pathway of enhancing thermotolerance in plant reproductive development.

Assessing the role of programmed cell death signatures and related gene TOP2A in progression and prognostic prediction of clear cell renal cell carcinoma.

Kidney Clear Cell Carcinoma (KIRC), the predominant form of kidney cancer, exhibits a diverse therapeutic response to Immune Checkpoint Inhibitors (ICIs), highlighting the need for predictive models of ICI efficacy. Our study has constructed a prognostic model based on 13 types of Programmed Cell Death (PCD), which are intertwined with tumor progression and the immune microenvironment. Validated by analyses of comprehensive datasets, this model identifies seven key PCD genes that delineate two subtypes with distinct immune profiles and sensitivities to anti-PD-1 therapy. The high-PCD group demonstrates a more immune-suppressive environment, while the low-PCD group shows better responses to PD-1 treatment. In particular, TOP2A emerged as crucial, with its inhibition markedly reducing KIRC cell growth and mobility. These findings underscore the relevance of PCDs in predicting KIRC outcomes and immunotherapy response, with implications for enhancing clinical decision-making.

Disrupted intercellular bridges and spermatogenesis in fatty acyl-CoA reductase 1 knockout mice: A new model of ether lipid deficiency.

Peroxisomal fatty acyl-CoA reductase 1 (FAR1) is a rate-limiting enzyme for ether lipid (EL) synthesis. Gene mutations in FAR1 cause a rare human disease. Furthermore, altered EL homeostasis has also been associated with various prevalent human diseases. Despite their importance in human health, the exact cellular functions of FAR1 and EL are not well-understood. Here, we report the generation and initial characterization of the first Far1 knockout (KO) mouse model. Far1 KO mice were subviable and displayed growth retardation. The adult KO male mice had smaller testes and were infertile. H&E and immunofluorescent staining showed fewer germ cells in seminiferous tubules. Round spermatids were present but no elongated spermatids or spermatozoa were observed, suggesting a spermatogenesis arrest at this stage. Large multi-nucleated giant cells (MGC) were found lining the lumen of seminiferous tubules with many of them undergoing apoptosis. The immunofluorescent signal of TEX14, an essential component of intercellular bridges (ICB) between developing germ cells, was greatly reduced and mislocalized in KO testis, suggesting the disrupted ICBs as an underlying cause of MGC formation. Integrative analysis of our total testis RNA-sequencing results and published single-cell RNA-sequencing data unveiled cell type-specific molecular alterations underlying the spermatogenesis arrest. Many genes essential for late germ cell development showed dramatic downregulation, whereas genes essential for extracellular matrix dynamics and cell-cell interactions were among the most upregulated genes. Together, this work identified the cell type-specific requirement of ELs in spermatogenesis and suggested a critical role of Far1/ELs in the formation/maintenance of ICB during meiosis.

Activation of Ca2+ transport in cardiac microsomes enriches functional sets of ER and SR proteins.

The importance of sarcoplasmic reticulum (SR) Ca2+-handling in heart has led to detailed understanding of Ca2+-release and re-uptake protein complexes, while less is known about other endoplasmic reticulum (ER) functions in the heart. To more fully understand cardiac SR and ER functions, we analyzed cardiac microsomes based on their increased density through the actions of the SR Ca2+-ATPase (SERCA) and the ryanodine receptor that are highly active in cardiomyocytes. Crude cardiac microsomal vesicles loaded with Ca oxalate produced two higher density subfractions, MedSR and HighSR. Proteins from 20.0 µg of MV, MedSR, and HighSR protein were fractionated using SDS-PAGE, then trypsinized from 20 separate gel pieces, and analyzed by LC-MS/MS to determine protein content. From 62,000 individual peptide spectra obtained, we identified 1105 different proteins, of which 354 were enriched ≥ 2.0-fold in SR fractions compared to the crude membrane preparation. Previously studied SR proteins were all enriched, as were proteins associated with canonical ER functions. Contractile, mitochondrial, and sarcolemmal proteins were not enriched. Comparing the levels of SERCA-positive SR proteins in MedSR versus HighSR vesicles produced a range of SR subfraction enrichments signifying differing levels of Ca2+ leak co-localized in the same membrane patch. All known junctional SR proteins were more enriched in MedSR, while canonical ER proteins were more enriched in HighSR membrane. Proteins constituting other putative ER/SR subdomains also exhibited average Esub enrichment values (mean ± S.D.) that spanned the range of possible Esub values, suggesting that functional sets of proteins are localized to the same areas of the ER/SR membrane. We conclude that active Ca2+ loading of cardiac microsomes, reflecting the combined activities of Ca2+ uptake by SERCA, and Ca2+ leak by RyR, permits evaluation of multiple functional ER/SR subdomains. Sets of proteins from these subdomains exhibited similar enrichment patterns across membrane subfractions, reflecting the relative levels of SERCA and RyR present within individual patches of cardiac ER and SR.

The evolutionary origin and domestication history of goldfish (Carassius auratus).

Goldfish have been subjected to over 1,000 y of intensive domestication and selective breeding. In this report, we describe a high-quality goldfish genome (2n = 100), anchoring 95.75% of contigs into 50 pseudochromosomes. Comparative genomics enabled us to disentangle the two subgenomes that resulted from an ancient hybridization event. Resequencing 185 representative goldfish variants and 16 wild crucian carp revealed the origin of goldfish and identified genomic regions that have been shaped by selective sweeps linked to its domestication. Our comprehensive collection of goldfish varieties enabled us to associate genetic variations with a number of well-known anatomical features, including features that distinguish traditional goldfish clades. Additionally, we identified a tyrosine-protein kinase receptor as a candidate causal gene for the first well-known case of Mendelian inheritance in goldfish-the transparent mutant. The goldfish genome and diversity data offer unique resources to make goldfish a promising model for functional genomics, as well as domestication.

A high-quality Brassica napus genome reveals expansion of transposable elements, subgenome evolution and disease resistance.

Rapeseed (Brassica napus L.) is a recent allotetraploid crop, which is well known for its high oil production. Here, we report a high-quality genome assembly of a typical semi-winter rapeseed cultivar, 'Zhongshuang11' (hereafter 'ZS11'), using a combination of single-molecule sequencing and chromosome conformation capture (Hi-C) techniques. Most of the high-confidence sequences (93.1%) were anchored to the individual chromosomes with a total of 19 centromeres identified, matching the exact chromosome count of B. napus. The repeat sequences in the A and C subgenomes in B. napus expanded significantly from 500 000 years ago, especially over the last 100 000 years. These young and recently amplified LTR-RTs showed dispersed chromosomal distribution but significantly preferentially clustered into centromeric regions. We exhaustively annotated the nucleotide-binding leucine-rich repeat (NLR) gene repertoire, yielding a total of 597 NLR genes in B. napus genome and 17.4% of which are paired (head-to-head arrangement). Based on the resequencing data of 991 B. napus accessions, we have identified 18 759 245 single nucleotide polymorphisms (SNPs) and detected a large number of genomic regions under selective sweep among the three major ecotype groups (winter, semi-winter and spring) in B. napus. We found 49 NLR genes and five NLR gene pairs colocated in selective sweep regions with different ecotypes, suggesting a rapid diversification of NLR genes during the domestication of B. napus. The high quality of our B. napus 'ZS11' genome assembly could serve as an important resource for the study of rapeseed genomics and reveal the genetic variations associated with important agronomic traits.

Mouse spermatogenesis-associated protein 1 (SPATA1), an IFT20 binding partner, is an acrosomal protein.

BACKGROUND: Intraflagellar transport is a motor-driven trafficking system that is required for the formation of cilia. Intraflagellar transport protein 20 (IFT20) is a master regulator for the control of spermatogenesis and male fertility in mice. However, the mechanism of how IFT20 regulates spermatogenesis is unknown. RESULTS: Spermatogenesis associated 1 (SPATA1) was identified to be a major potential binding partner of IFT20 by a yeast two-hybrid screening. The interaction between SPATA1 and IFT20 was examined by direct yeast two-hybrid, co-localization, and co-immunoprecipitation assays. SPATA1 is highly abundant in the mouse testis, and is also expressed in the heart and kidney. During the first wave of spermatogenesis, SPATA1 is detectable at postnatal day 24 and its expression is increased at day 30 and 35. Immunofluorescence staining of mouse testis sections and epididymal sperm demonstrated that SPATA1 is localized mainly in the acrosome of developing spermatids but not in epididymal sperm. IFT20 is also present in the acrosome area of round spermatids. In conditional Ift20 knockout mice, testicular expression level and acrosomal localization of SPATA1 are not changed. CONCLUSIONS: SPATA1 is an IFT20 binding protein and may provide a docking site for IFT20 complex binding to the acrosome area.

Androgen aggravates liver fibrosis by activation of NLRP3 inflammasome in CCl4-induced liver injury mouse model.

Studies have shown that there are differences between the sexes regarding to the occurrence and development of liver diseases, which may be associated with sex hormones. However, the mechanisms behind it are largely unknown. In this study, we first investigated the differences of liver injury between male and female mice, using the CCl4-induced liver injury mouse model. It showed that the liver damage of male mice was much more severe than that of female mice. Both the acute injury and fibrosis of the liver were reduced when androgens were depleted by castration of male mice. The vulnerability of male liver was associated with testis endocrine and excessive activation of inflammatory response in the liver. Castrated male mice with testosterone supplementation showed aggravated liver inflammatory response and fibrosis. The activity of NOD-like receptor protein 3 (NLRP3) inflammasome was increased when testosterone supplementation was provided. However, the enhanced inflammatory response and fibrosis due to testosterone supplementation were negated by inhibiting the activation of NLRP3 using the specific small molecule inhibitor MCC950. It suggests that testosterone is a key factor that influences liver injury by regulating the NLRP3 inflammasome activation-mediated inflammatory response.

CK19 stabilizes CFTR at the cell surface by limiting its endocytic pathway degradation.

Protein interactions that stabilize the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) at the apical membranes of epithelial cells have not yet been fully elucidated. We identified keratin 19 (CK19 or K19) as a novel CFTR-interacting protein. CK19 overexpression stabilized both wild-type (WT)-CFTR and Lumacaftor (VX-809)-rescued F508del-CFTR (where F508del is the deletion of the phenylalanine residue at position 508) at the plasma membrane (PM), promoting Cl- secretion across human bronchial epithelial (HBE) cells. CK19 prevention of Rab7A-mediated lysosomal degradation was a key mechanism in apical CFTR stabilization. Unexpectedly, CK19 expression was decreased by ∼40% in primary HBE cells from homogenous F508del patients with CF relative to non-CF controls. CK19 also positively regulated multidrug resistance-associated protein 4 expression at the PM, suggesting that this keratin may regulate the apical expression of other ATP-binding cassette proteins as well as CFTR.-Hou, X., Wu, Q., Rajagopalan, C., Zhang, C., Bouhamdan, M., Wei, H., Chen, X., Zaman, K., Li, C., Sun, X., Chen, S., Frizzell, R. A., Sun, F. CK19 stabilizes CFTR at the cell surface by limiting its endocytic pathway degradation.

Regulation of hepatic autophagy by stress-sensing transcription factor CREBH.

Autophagy, a lysosomal degradative pathway in response to nutrient limitation, plays an important regulatory role in lipid homeostasis upon energy demands. Here, we demonstrated that the endoplasmic reticulum-tethered, stress-sensing transcription factor cAMP-responsive element-binding protein, hepatic-specific (CREBH) functions as a major transcriptional regulator of hepatic autophagy and lysosomal biogenesis in response to nutritional or circadian signals. CREBH deficiency led to decreased hepatic autophagic activities and increased hepatic lipid accumulation upon starvation. Under unfed or during energy-demanding phases of the circadian cycle, CREBH is activated to drive expression of the genes encoding the key enzymes or regulators in autophagosome formation or autophagic process, including microtubule-associated protein 1B-light chain 3, autophagy-related protein (ATG)7, ATG2b, and autophagosome formation Unc-51 like kinase 1, and the genes encoding functions in lysosomal biogenesis and homeostasis. Upon nutrient starvation, CREBH regulates and interacts with peroxisome proliferator-activated receptor α (PPARα) and PPARγ coactivator 1α to synergistically drive expression of the key autophagy genes and transcription factor EB, a master regulator of lysosomal biogenesis. Furthermore, CREBH regulates rhythmic expression of the key autophagy genes in the liver in a circadian-dependent manner. In summary, we identified CREBH as a key transcriptional regulator of hepatic autophagy and lysosomal biogenesis for the purpose of maintaining hepatic lipid homeostasis under nutritional stress or circadian oscillation.-Kim, H., Williams, D., Qiu, Y., Song, Z., Yang, Z., Kimler, V., Goldberg, A., Zhang, R., Yang, Z., Chen, X., Wang, L., Fang, D., Lin, J. D., Zhang, K. Regulation of hepatic autophagy by stress-sensing transcription factor CREBH.

Adaptive methylation regulation of p53 pathway in sympatric speciation of blind mole rats, Spalax.

Epigenetic modifications play significant roles in adaptive evolution. The tumor suppressor p53, well known for controlling cell fate and maintaining genomic stability, is much less known as a master gene in environmental adaptation involving methylation modifications. The blind subterranean mole rat Spalax eherenbergi superspecies in Israel consists of four species that speciated peripatrically. Remarkably, the northern Galilee species Spalax galili (2n = 52) underwent adaptive ecological sympatric speciation, caused by the sharply divergent chalk and basalt ecologies. This was demonstrated by mitochondrial and nuclear genomic evidence. Here we show that the expression patterns of the p53 regulatory pathway diversified between the abutting sympatric populations of S. galili in sharply divergent chalk-basalt ecologies. We identified higher methylation on several sites of the p53 promoter in the population living in chalk soil (chalk population). Site mutagenesis showed that methylation on these sites linked to the transcriptional repression of p53 involving Cut-Like Homeobox 1 (Cux1), paired box 4 (Pax 4), Pax 6, and activator protein 1 (AP-1). Diverse expression levels of p53 between the incipiently sympatrically speciating chalk-basalt abutting populations of S. galili selectively affected cell-cycle arrest but not apoptosis. We hypothesize that methylation modification of p53 has adaptively shifted in supervising its target genes during sympatric speciation of S. galili to cope with the contrasting environmental stresses of the abutting divergent chalk-basalt ecologies.

Cataloging Plant Genome Structural Variations.

Structural variation (SV) is a type of genetic variation identified through the comparison of genome structures which often have direct and significant associations with phenotypic variations. Building on the next generation sequencing (NGS) technologies, research on plant structural variations are gaining momentum and have revolutionized our view on the functional impact of the 'hidden' diversity that were largely understudied before. Herein, we first describe the current state of plant genomic SV research based on NGS and in particular focus on the biological insights gained from the large-scale identification of various types of plant SVs. Specific examples are chosen to demonstrate the genetic basis for phenotype diversity in model plant and major agricultural crops. Additionally, development of new genomic mapping technologies, including optical mapping and long read sequencing, as well as improved computational algorithms associated with these technologies have helped to pinpoint the exact nature and location of genomic SVs with much better resolution and precision. Future direction of plant research on SVs should focus on the population level to build a comprehensive catalog of SVs, leading to full assessment of their impact on biological diversity.

Remote ischemic preconditioning fails to reduce infarct size in the Zucker fatty rat model of type-2 diabetes: role of defective humoral communication.

Remote ischemic preconditioning (RIPC), the phenomenon whereby brief ischemic episodes in distant tissues or organs render the heart resistant to infarction, has been exhaustively demonstrated in preclinical models. Moreover, emerging evidence suggests that exosomes play a requisite role in conveying the cardioprotective signal from remote tissue to the myocardium. However, in cohorts displaying clinically common comorbidities-in particular, type-2 diabetes-the infarct-sparing effect of RIPC may be confounded for as-yet unknown reasons. To investigate this issue, we used an integrated in vivo and in vitro approach to establish whether: (1) the efficacy of RIPC is maintained in the Zucker fatty rat model of type-2 diabetes, (2) the humoral transfer of cardioprotective triggers initiated by RIPC are transported via exosomes, and (3) diabetes is associated with alterations in exosome-mediated communication. We report that a standard RIPC stimulus (four 5-min episodes of hindlimb ischemia) reduced infarct size in normoglycemic Zucker lean rats, but failed to confer protection in diabetic Zucker fatty animals. Moreover, we provide novel evidence, via transfer of serum and serum fractions obtained following RIPC and applied to HL-1 cardiomyocytes subjected to hypoxia-reoxygenation, that diabetes was accompanied by impaired humoral communication of cardioprotective signals. Specifically, our data revealed that serum and exosome-rich serum fractions collected from normoglycemic rats attenuated hypoxia-reoxygenation-induced HL-1 cell death, while, in contrast, exosome-rich samples from Zucker fatty rats did not evoke protection in the HL-1 cell model. Finally, and unexpectedly, we found that exosome-depleted serum from Zucker fatty rats was cytotoxic and exacerbated hypoxia-reoxygenation-induced cardiomyocyte death.

Formation and transformation of chloroform during managed aquifer recharge (MAR).

Chlorination is an effective method to protect the safety of groundwater systems during managed aquifer recharge. However, chlorination leads to the formation of disinfection by-products, whose behavior in aquifers remains unclear and has caused public concern. In this study, an in-site test was performed on an anoxic aquifer in Shouguang City, China, to investigate the formation and transformation of chloroform during managed aquifer recharge. The field tests showed that the formation of chloroform in groundwater caused by the recharge of chlorinated water, and that the fate of chloroform was affected by adsorption and biodegradation. The retardation factor was 1.27, and the half-life was 29 days. The formation and transformation of chloroform during continuous recharge under different hydrochemical conditions was further investigated by batch experiments. These experiments showed that the formation of chloroform increased with contact time, tended to be stable after 10 h, and was facilitated by high chloride/TOC ratios, high pH, and low ionic strength (IS) for a given contact time. The adsorption experiments showed that the process accords with the pseudo-second-order kinetic equations and the Freundlich model. The adsorption capacity was pH dependent (1.01-1.66 µg/g at pH 5 and 2.17-3.05 µg/g at pH 9). Increasing the IS promotes adsorption. The results from biodegradation experiments indicated that the biodegradation was well fitted by the Monod equation. The retardation factor in the batch experiments was close to that of the field test, but the half-life was less than the field test. This is mainly due to the difference in the concentration of dissolved oxygen.

Mechanoregulation of SM22α/Transgelin.

SM22α, also named transgelin, is an actin filament-associated protein in smooth muscle and fibroblasts. Three decades after its discovery, the biological function of SM22α remains under investigation. Here we report a novel finding that the expression and degradation of SM22α/transgelin are regulated by mechanical tension. Following a mass spectrometry identification of SM22α degradation in isolated and tension-unloaded mouse aorta, we developed specific monoclonal antibodies to study the regulation of SM22α in human fetal lung myofibroblast line MRC-5 and primary cultures of neonatal mouse skin fibroblasts. The level of SM22α is positively related to the mechanical tension in the cytoskeleton produced by the myosin II motor in response to the stiffness of the culture matrix. Quantitative reverse transcription polymerase chain reaction demonstrated that the expression of SM22α is regulated at the transcriptional level. This mechanical regulation resembles that of calponin 2, another actin filament-associated protein. Immunofluorescent staining co-localized SM22α with F-actin, myosin, and calponin 2 in mouse skin fibroblasts. The close phylogenetic relationship between SM22α and the calponin family supports that SM22α is a calponin-like regulatory protein. The level of SM22α is decreased in skin fibroblasts isolated from calponin 2 knockout mice, suggesting interrelated regulation and function of the two proteins. On the other hand, SM22α expression was maximized at a matrix stiffness higher than that for calponin 2 in the same cell type, indicating differentiated regulation and tension responsiveness. The novel mechanoregulation of SM22α/transgelin lays the groundwork for understanding its cellular functions.

Pathomimetic avatars reveal divergent roles of microenvironment in invasive transition of ductal carcinoma in situ.

BACKGROUND: The breast tumor microenvironment regulates progression of ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC). However, it is unclear how interactions between breast epithelial and stromal cells can drive this progression and whether there are reliable microenvironmental biomarkers to predict transition of DCIS to IDC. METHODS: We used xenograft mouse models and a 3D pathomimetic model termed mammary architecture and microenvironment engineering (MAME) to study the interplay between human breast myoepithelial cells (MEPs) and cancer-associated fibroblasts (CAFs) on DCIS progression. RESULTS: Our results show that MEPs suppress tumor formation by DCIS cells in vivo even in the presence of CAFs. In the in vitro MAME model, MEPs reduce the size of 3D DCIS structures and their degradation of extracellular matrix. We further show that the tumor-suppressive effects of MEPs on DCIS are linked to inhibition of urokinase plasminogen activator (uPA)/urokinase plasminogen activator receptor (uPAR)-mediated proteolysis by plasminogen activator inhibitor 1 (PAI-1) and that they can lessen the tumor-promoting effects of CAFs by attenuating interleukin 6 (IL-6) signaling pathways. CONCLUSIONS: Our studies using MAME are, to our knowledge, the first to demonstrate a divergent interplay between MEPs and CAFs within the DCIS tumor microenvironment. We show that the tumor-suppressive actions of MEPs are mediated by PAI-1, uPA and its receptor, uPAR, and are sustained even in the presence of the CAFs, which themselves enhance DCIS tumorigenesis via IL-6 signaling. Identifying tumor microenvironmental regulators of DCIS progression will be critical for defining a robust and predictive molecular signature for clinical use.

Overactivation of corticotropin-releasing factor receptor type 1 and aquaporin-4 by hypoxia induces cerebral edema.

Cerebral edema is a potentially life-threatening illness, but knowledge of its underlying mechanisms is limited. Here we report that hypobaric hypoxia induces rat cerebral edema and neuronal apoptosis and increases the expression of corticotrophin releasing factor (CRF), CRF receptor type 1 (CRFR1), aquaporin-4 (AQP4), and endothelin-1 (ET-1) in the cortex. These effects, except for the increased expression of CRF itself, could all be blocked by pretreatment with an antagonist of the CRF receptor CRFR1. We also show that, in cultured primary astrocytes: (i) both CRFR1 and AQP4 are expressed; (ii) exogenous CRF, acting through CRFR1, triggers signaling of cAMP/PKA, intracellular Ca(2+), and PKCε; and (iii) the up-regulated cAMP/PKA signaling contributes to the phosphorylation and expression of AQP4 to enhance water influx into astrocytes and produces an up-regulation of ET-1 expression. Finally, using CHO cells transfected with CRFR1(+) and AQP4(+), we show that transfected CRFR1(+) contributes to edema via transfected AQP4(+). In conclusion, hypoxia triggers cortical release of CRF, which acts on CRFR1 to trigger signaling of cAMP/PKA in cortical astrocytes, leading to activation of AQP4 and cerebral edema.