Lower Childhood Socioeconomic Status Is Associated with Greater Neural Responses to Ambient Auditory Changes in Adulthood.

Humans' early life experience varies by socioeconomic status (SES), raising the question of how this difference is reflected in the adult brain. An important aspect of brain function is the ability to detect salient ambient changes while focusing on a task. Here, we ask whether subjective social status during childhood is reflected by the way young adults' brain detecting changes in irrelevant information. In two studies (total n = 58), we examine electrical brain responses in the frontocentral region to a series of auditory tones, consisting of standard stimuli (80%) and deviant stimuli (20%) interspersed randomly, while participants were engaged in various visual tasks. Both studies showed stronger automatic change detection indexed by MMN in lower SES individuals, regardless of the unattended sound's feature, attended emotional content, or study type. Moreover, we observed a larger MMN in lower-SES participants, although they did not show differences in brain and behavior responses to the attended task. Lower-SES people also did not involuntarily orient more attention to sound changes (i.e., deviant stimuli), as indexed by the P3a. The study indicates that individuals with lower subjective social status may have an increased ability to automatically detect changes in their environment, which may suggest their adaptation to their childhood environments.

Precipitation- rather than temperature-driven pattern in belowground biomass and root:shoot ratio across the Qinghai-Tibet Plateau.

The Qinghai-Tibet Plateau faces dramatic global change, which can greatly affect its plant growth, biomass accumulation, and carbon cycling. However, it is still unclear how belowground plant biomass, which is the major part of vegetation biomass on the plateau, changes with different environmental factors, impeding accurate prediction of ecosystem carbon cycling under future global change scenarios. To reveal the patterns of belowground biomass and root:shoot ratio with environmental factors in different vegetation types on the Qinghai-Tibet Plateau, we synthesized data for 158 sites from 167 publications, including 585 and 379 observations for above- and below-ground biomass, respectively. Data on temperature, precipitation, soil nitrogen content, evapotranspiration and solar radiation were collected from open databases. The results showed that precipitation, rather than temperature, was closely associated with other environmental factors including soil N and solar radiation. Also, both above- and below-ground biomass significantly increased with annual precipitation and its related environmental factors, while elevation-related coldness only slightly decreased aboveground biomass. In addition, the positive effect of precipitation on belowground biomass is more obvious in higher elevations (colder areas). As a result, root:shoot ratio significantly increased with precipitation in colder areas but not in warmer areas. Finally, the positive relationship between biomass and precipitation was stronger for dryer steppes than for wetter meadows and shrublands. Our findings indicate that precipitation, as well as the associated nitrogen availability and solar radiation, together are more important drivers than temperature for ecosystem productivity and biomass allocation on the Qinghai-Tibet Plateau. Given the heterogeneous trend of precipitation change on the plateau, productivity response to global change can be highly variable across different regions and vegetation types, which can consequently impact soil carbon dynamics and regional carbon cycling.

Myelodysplastic syndrome-like response after voriconazole treatment of systemic lupus erythematosus complicated with fungal infection: a case report.

Background: Voriconazole is mainly used to treat progressive and potentially life-threatening infections in immunocompromised patients. The adverse drug reactions related to voriconazole are varied. In some rare cases, the use of voriconazole can result in myelodysplastic syndrome (MDS)-like adverse reactions. Case presentation: Here, we present a rare case of systemic lupus erythematosus patient with a fungal infection that developed MDS-like adverse reactions after treatment with voriconazole. The patient was admitted to the hospital because of 3 days of chest tightness and dyspnea. After the admission, the patient's sputum culture showed Candida albicans infection, and voriconazole was prescribed to be taken orally. After using voriconazole, drug-related adverse reactions such as visual impairment, nausea, vomiting, hiccup, middle and lower abdominal pain, disorders of consciousness, delirium, hallucination, slow response, and subcutaneous ecchymosis appeared, as well as the gradually increased serum creatinine, oliguria, and aggravated lower limb edema. In addition, there was a decrease in peripheral blood cells, and MDS-like changes in bone marrow were indicated by bone marrow biopsy. After discontinuing voriconazole, drug-related adverse symptoms disappeared, and hematocytopenia and the changes in MDS were significantly improved, which was confirmed by a subsequent bone marrow puncture at a 6 months interval. Conclusion: This case reminded us that when using voriconazole for treatment, individual differences in patients should be considered, and the blood concentration of voriconazole should be closely monitored. Otherwise, potential drugs that affect voriconazole metabolism should be noted, and related adverse symptoms of patients should be closely observed during medication to reduce the occurrence of adverse drug events.

MSATNet: multi-scale adaptive transformer network for motor imagery classification.

Motor imagery brain-computer interface (MI-BCI) can parse user motor imagery to achieve wheelchair control or motion control for smart prostheses. However, problems of poor feature extraction and low cross-subject performance exist in the model for motor imagery classification tasks. To address these problems, we propose a multi-scale adaptive transformer network (MSATNet) for motor imagery classification. Therein, we design a multi-scale feature extraction (MSFE) module to extract multi-band highly-discriminative features. Through the adaptive temporal transformer (ATT) module, the temporal decoder and multi-head attention unit are used to adaptively extract temporal dependencies. Efficient transfer learning is achieved by fine-tuning target subject data through the subject adapter (SA) module. Within-subject and cross-subject experiments are performed to evaluate the classification performance of the model on the BCI Competition IV 2a and 2b datasets. The MSATNet outperforms benchmark models in classification performance, reaching 81.75 and 89.34% accuracies for the within-subject experiments and 81.33 and 86.23% accuracies for the cross-subject experiments. The experimental results demonstrate that the proposed method can help build a more accurate MI-BCI system.

Integrative Analysis of DNA Methylation and Gene Expression Data Identifies Potential Biomarkers and Functional Epigenetic Modules for SARS-CoV-2.

To integrate gene expression and DNA methylation data and find the potential role of DNA methylation in the invasion and replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We first conducted differential expression and methylation analysis between the coronavirus disease of 2019 (COVID-19) and healthy controls. FEM was employed to identify functional epigenetic modules, from which a diagnostic model for COVID-19 was built. SKA1 and WSB1 modules were identified, with SKA1 module enriched in COVID-19 replication and transcription, and WSB1 module related to ubiquitin-protein activity. The differentially expressed or differentially methylated genes in these two modules could be used to distinguish COVID-19 from healthy controls, with AUC reaching 1 and 0.98 for SKA1 and WSB1 modules, respectively. Two epigenetically activated genes (CENPM and KNL1) from the SKA1 module were upregulated in HPV- or HBV-positive tumor samples and were found to be significantly associated with the survival of tumor patients. In conclusion, the identified FEM modules and potential signatures play an essential role in the replication and transcription of coronavirus.

A neuroimaging study of brain activity alterations in treatment-resistant depression after a dual target accelerated transcranial magnetic stimulation.

In this study, we designed a new transcranial magnetic stimulation (TMS) protocol using a dual-target accelerated transcranial magnetic stimulation (aTMS) for patients with treatment resistant depression (TRD). There are 58 TRD patients were recruited from the Second People's Hospital of Guizhou Province, who were, respectively, received dual-target (real continuous theta burst stimulation (cTBS) at right orbitofrontal cortex (OFC) and real repetitive transcranial magnetic stimulation (rTMS) at left dorsolateral prefrontal cortex (DLPFC)), single- target (sham cTBS at right OFC and real rTMS at left DLPFC), and sham stimulation (sham cTBS at right OFC and sham rTMS at left DLPFC). Resting-state functional magnetic resonance imaging (rs-fMRI) was acquired before and after aTMS treatment to compare characteristics of brain activities by use of amplitude of low-frequency fluctuations (ALFF), fractional low-frequency fluctuations (fALFF) and functional connectivity (FC). At the same time, Hamilton Depression Scale-24 (HAMD24) were conducted to assess the effect. HAMD24 scores reduced significantly in dual group comparing to the single and sham group. Dual-target stimulation decreased not only the ALFF values of right fusiform gyrus (FG) and fALFF values of the left superior temporal gyrus (STG), but also the FC between the right FG and the bilateral middle frontal gyrus (MFG), left triangular part of inferior frontal gyrus (IFG). Higher fALFF value in left STG at baseline may predict better reaction for bilateral arTMS. Dual-targe stimulation can significantly change resting-state brain activities and help to improve depressive symptoms.

Effects of nutrient heterogeneity on root foraging and plant growth at the individual and community level.

Plants enhance nutrient uptake in heterogeneous nutrient environments through selective root placement. Many studies have documented that plants grow better under heterogeneous than under homogeneous nutrient distribution, but comprehensive syntheses are relatively few. In a meta-analysis, we examined the effects of patch scale and contrast on plant responses by synthesizing the effects of nutrient heterogeneity on root foraging and plant growth in 131 comparative studies. Plant responses to nutrient heterogeneity were phylogenetically conserved, and the response in shoot biomass was significantly correlated with the response in root biomass but not with root foraging precision. Root precision depended on the competition regime, and plants had lower precision in interspecific than in conspecific competition. Community-level growth was significantly promoted by nutrient heterogeneity and was less variable than individual-level responses. Along with increasing patch scale, overall shoot and root responses of individuals increased but root foraging precision declined. In addition, moderate patch contrast induced the highest root responses. Our results indicate that plants optimize nutrient acquisition from heterogeneous patches mainly through increasing root growth, and plant communities exploit heterogeneous nutrients more effectively than individuals. Understanding the roles of patch attributes in nutrient-heterogeneity effects may help in designing fertilization practices to promote productivity and conserve biodiversity.

A vortex method of 3D smoke simulation for virtual surgery.

BACKGROUND AND OBJECTIVE: A realistic virtual surgery simulation needs to simulate smoke as electrical cutting causes thermal tissue damage. The vortex particle method of simulating smoke can realistically present the vortex details and motion trajectory of the smoke, but there is high computational cost. METHODS: To address this problem, we propose the 3D Vortex Particles in Cube Algorithm (3D-VPICA). 3D-VPICA can realistically show the visual effect of smoke and reduce the computational cost. In addition, in order to enhance the reality of the smoke, we propose the Auxiliary Particles Algorithm (APA) method to deal with the collision problem of smoke. RESULTS: The 3D-VPICA can calculate the velocity of the vortex particles speedily with the help of cube grids and with the complexity decreasing from O(N2) to O(N) + O(Mlog 2M). The APA can ensure that boundary conditions are satisfied when the smoke collides with irregular surfaces. Experimental results show that 3D-VPICA is faster than traditional methods of smoke simulation and that APA is successful in simulating smoke colliding with moving objects with irregular surfaces. CONCLUSIONS: The proposed 3D smoke simulation method was applied to a virtual surgery system using a high frequency electric knife. The cutting and coagulate operations were fluent and the smoke flowed with fidelity.

A Highlight-Generation Method for Rendering Translucent Objects.

The acquisition of translucent objects has become a very common task thanks to the progress of 3D scanning technology. Since the characteristic soft appearance of translucent objects is due to subsurface scattering, the details are naturally left out in this appearance. For objects that have complex shapes, this lack of detail is obviously more prominent. In this paper, we propose a method to preserve the details of surface geometry by adding highlight effects. In generating highlight effects, our method employs a local orthonormal frame and combines, in a novel way, the incoming and outgoing light in approximating the subsurface scattering process. When the incident illuminant direction changes from nearly overhead to nearly horizontal, our method effectively preserves complex surface geometry details in the appearance of translucent materials. Through experiments, we show that our method can store surface features as well as maintain the translucency of the original materials and even enhance the perception of translucency. By numerically comparing the generated highlight effects with those generated by the traditional Bidirectional Reflectance Distribution Function (BRDF) models with different bandwidth parameters, we demonstrate the validity of our proposed method.

[Efficacy and safety of deferasirox in aplastic anemia patients with iron overload: a single arm, multi-center,prospective study in China].

OBJECTIVE: To explore the efficacy and safety of deferasirox in aplastic anemia (AA)patients with iron overload. METHODS: A single arm, multi- center, prospective, open- label study was conducted to evaluate absolute change in serum ferritin (SF)from baseline to 12 months of deferasirox administration, initially at a dose of 20 mg·kg(-1)·d(-1), and the safety in 64 AA patients with iron overload. RESULTS: All patients started their deferasirox treatment with a daily dose of 20 mg · kg(-1) ·d(-1). The mean actual dose was (18.6±3.60) mg · kg(-1)·d(-1). The median SF decreased from 4 924 (2 718- 6 765)µg/L at baseline (n=64) to 3 036 (1 474- 5 551)µg/L at 12 months (n=23) with the percentage change from baseline as 38%. A median SF decrease of 651 (126-2 125)µg/L was observed at the end of study in 23 patients who completed 12 months' treatment, the median SF level decreased by 1 167(580-4 806)µg/L [5 271(3 420-8 278)µg/L at baseline; 3 036(1 474-5 551)µg/L after 12 months' treatment; the percentage change from baseline as 42% ] after 12 months of deferasirox treatment. The most common adverse events (AEs) were increased serum creatinine levels (40.98%), gastrointestinal discomfort (40.98%), elevated liver transaminase (ALT: 21.31%; AST: 13.11%)and proteinuria (24.59%). The increased serum creatinine levels were reversible and non-progressive. Of 38 patients with concomitant cyclosporine use, 12(31.8%)patients had two consecutive values >ULN, 10(26.3%)patients had two consecutive values >1.33 baseline values, but only 1(2.6%)patient's serum creatinine increased more than 1.33 baseline values and exceeded ULN. For both AST and ALT, no patients experienced two post- baseline values >5 ×ULN or >10 × ULN during the whole study. In AA patients with low baseline PLT count (less than 50 × 10(9)/L), there was no decrease for median PLT level during 12 months' treatment period. CONCLUSIONS: AA patients with iron overload could achieve satisfactory efficacy of iron chelation by deferasirox treatment. The drug was well tolerated with a clinically manageable safety profile and no major adverse events.

Apoptosis in human myelodysplastic syndrome CD34+ cells is modulated by the upregulation of TLRs and histone H4 acetylation via a ß-arrestin 1 dependent mechanism.

Excessive apoptosis of hematopoietic precursors in the bone marrow underlies the ineffective hematopoiesis characteristic of myelodysplastic syndrome (MDS). Toll-like receptor (TLR) signaling is abnormally activated in MDS and may be involved in excessive programmed cell death in the pathogenesis of MDS. TLRs expression and global histone H3/H4 acetylation were analyzed in bone marrow (BM) CD34+ cells from 20 lower-risk and 20 higher-risk MDS patients and 10 healthy controls. Apoptosis of BM CD34+ cells was examined by flow cytometry, and its correlation to histone acetylation and the expression of TLR2 and ß-arrestin1 (ß-arr1), measured by enzyme-linked immunosorbent assay and qRT-PCR, was assessed. TLR1, TLR2 and TLR6 expression and H4 acetylation levels were higher in lower-risk MDS patients than in higher-risk MDS patients or controls, and TLR2 expression and H4 acetylation levels were positively correlated with an increased rate of apoptosis. Lower-risk MDS was associated with increased ß-arr1 expression and histone acetyltransferase p300 activity. In in vitro-cultured primary normal and lower-risk MDS CD34+ cells, TLR2 activation-induced apoptosis was mediated by the upregulation of ß-arr1 leading to the recruitment of p300 and increased histone H4 acetylation. The nuclear accumulation of ßarr1 following TLR2 activation promote H4 acetylation at specific target gene promoters and may thus affect transcription of target genes in BM CD34+ cells. The mechanisms underlying the deregulation of TLR2 and increased apoptosis in MDS may involve the ß-arr1 mediated recruitment of p300 leading to increased levels of histone H4 acetylation.

Two compound frame-shift mutations in succinate dehydrogenase gene of a Chinese boy with encephalopathy.

OBJECTIVE: To investigate respiratory chain complex II deficiency resulted from mutation in succinate dehydrogenase gene (SDH) encoding complex II subunits in China. METHODS: An 11-year-old boy was admitted to our hospital. He had a history of progressive psychomotor regression and weakness since the age of 4years. His cranial magnetic resonance imaging revealed focal, bilaterally symmetrical lesions in the basal ganglia and thalamus, indicating mitochondrial encephalopathy. The activities of mitochondrial respiratory chain enzymes I-V in peripheral leukocytes were determined via spectrophotometry. Mitochondrial DNA and the succinate dehydrogenase A (SDHA) gene were analyzed by direct sequencing. RESULTS: Complex II activity in the leukocytes had decreased to 33.07nmol/min/mg mitochondrial protein (normal control 71.8±12.9); the activities of complexes I, III, IV and V were normal. The entire sequence of the mitochondrial DNA was normal. The SDHA gene showed two heterozygous frame-shift mutations: c.G117G/del in exon 2 and c.T220T/insT in exon 3, which resulted in stop codons at residues 56 and 81, respectively. CONCLUSIONS: We have described the first Chinese case of mitochondrial respiratory chain complex II deficiency, which was diagnosed using enzyme assays and gene analysis. Two novel, compound, frame-shift mutations, c.G117G/del in exon 2 and c.T220T/insT in exon 3 of the SDHA gene, were found in our patient.

Heterogeneity of six children and their mothers with mitochondrial DNA 3243 A>G mutation.

To study the clinical, biochemical, and genetic heterogeneity of six Chinese patients and their mothers with the 3243 A>G mutation, six patients (ranging from 5 to 11 years) were hospitalized. All the mothers were healthy. Mitochondrial respiratory chain enzyme activities were determined by spectrophotometry. Mitochondrial gene was analyzed in all patients. Six core pedigrees were investigated. Two patients had mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes syndrome and one had Leigh syndrome. The common initial symptoms were headache, vomiting, blurred vision, and epilepsy. m.3243A>G mutation was detected in all patients and their mothers. The mutation loads ranged from 43.6% to 58% and those of their mothers ranged from 14.1% to 28.6%. Varied respiratory chain deficiencies were observed in all patients and two mothers. m.3243A>G mutation can result in a wide spectrum of respiratory chain complex deficiencies. Mitochondrial DNA mutation detected in blood may be likely to transmit to offspring, and the mutation load may increase.

Stabilized beta-catenin in lung epithelial cells changes cell fate and leads to tracheal and bronchial polyposis.

The precise mechanisms by which beta-catenin controls morphogenesis and cell differentiation remain largely unknown. Using embryonic lung development as a model, we deleted exon 3 of beta-catenin via Nkx2.1-cre in the Catnb[+/lox(ex3)] mice and studied its impact on epithelial morphogenesis. Robust selective accumulation of truncated, stabilized beta-catenin was found in Nkx2.1-cre;Catnb[+/lox(ex3)] lungs that were associated with the formation of polyp-like structures in the trachea and main-stem bronchi. Characterization of polyps suggests that accumulated beta-catenin impacts epithelial morphogenesis in at least two ways. "Intracellular" accumulation of beta-catenin blocked differentiation of spatially-appropriate airway epithelial cell types, Clara cells, ciliated cells and basal cells, and activated UCHL1, a marker for pulmonary neuroendocrine cells. There was also evidence for a "paracrine" impact of beta-catenin accumulation, potentially mediated via activation of Bmp4 that inhibited Clara and ciliated, but not basal cell differentiation. Thus, excess beta-catenin can alter cell fate determination by both direct and paracrine mechanisms.

Mesodermal deletion of transforming growth factor-beta receptor II disrupts lung epithelial morphogenesis: cross-talk between TGF-beta and Sonic hedgehog pathways.

In vertebrates, Sonic hedgehog (Shh) and transforming growth factor-beta (TGF-beta) signaling pathways occur in an overlapping manner in many morphogenetic processes. In vitro data indicate that the two pathways may interact. Whether such interactions occur during embryonic development remains unknown. Using embryonic lung morphogenesis as a model, we generated transgenic mice in which exon 2 of the TbetaRII gene, which encodes the type II TGF-beta receptor, was deleted via a mesodermal-specific Cre. Mesodermal-specific deletion of TbetaRII (TbetaRII(Delta/Delta)) resulted in embryonic lethality. The lungs showed abnormalities in both number and shape of cartilage in trachea and bronchi. In the lung parenchyma, where epithelial-mesenchymal interactions are critical for normal development, deletion of mesenchymal TbetaRII caused abnormalities in epithelial morphogenesis. Failure in normal epithelial branching morphogenesis in the TbetaRII(Delta/Delta) lungs caused cystic airway malformations. Interruption of the TbetaRII locus in the lung mesenchyme increased mRNA for Patched and Gli-1, two downstream targets of Shh signaling, without alterations in Shh ligand levels produced in the epithelium. Therefore, we conclude that TbetaRII-mediated signaling in the lung mesenchyme modulates transduction of Shh signaling that originates from the epithelium. To our knowledge, this is the first in vivo evidence for a reciprocal and novel mode of cross-communication between Shh and TGF-beta pathways during embryonic development.

Mechanisms of TGFbeta inhibition of LUNG endodermal morphogenesis: the role of TbetaRII, Smads, Nkx2.1 and Pten.

Transforming growth factor-beta is a multifunctional growth factor with roles in normal development and disease pathogenesis. One such role is in inhibition of lung branching morphogenesis, although the precise mechanism remains unknown. In an explant model, all three TGFbeta isoforms inhibited FGF10-induced morphogenesis of mesenchyme-free embryonic lung endoderm. Inhibition of budding by TGFbeta was partially abrogated in endodermal explants from Smad3(-/-) or conditional endodermal-specific Smad4(Delta/Delta) embryonic lungs. Endodermal explants from conditional TGFbeta receptor II knockout lungs were entirely refractive to TGFbeta-induced inhibition. Inhibition of morphogenesis was associated with dedifferentiation of endodermal cells as documented by a decrease in key transcriptional factor, NKX2.1 protein, and its downstream target, surfactant protein C (SpC). TGFbeta reduced the proliferation of wild-type endodermal cells within the explants as assessed by BrdU labeling. Gene expression analysis showed increased levels of mRNA for Pten, a key regulator of cell proliferation. Conditional, endodermal-specific deletion of Pten overcame TGFbeta's inhibitory effect on cell proliferation, but did not restore morphogenesis. Thus, the mechanisms by which TGFbeta inhibits FGF10-induced lung endodermal morphogenesis may entail both inhibition of cell proliferation, through increased Pten, as well as inhibition or interference with morphogenetic mediators such as Nkx2.1. Both of the latter are dependent on signaling through TbetaRII.

Ror2 modulates the canonical Wnt signaling in lung epithelial cells through cooperation with Fzd2.

BACKGROUND: Wnt signaling is mediated through 1) the beta-catenin dependent canonical pathway and, 2) the beta-catenin independent pathways. Multiple receptors, including Fzds, Lrps, Ror2 and Ryk, are involved in Wnt signaling. Ror2 is a single-span transmembrane receptor-tyrosine kinase (RTK). The functions of Ror2 in mediating the non-canonical Wnt signaling have been well established. The role of Ror2 in canonical Wnt signaling is not fully understood. RESULTS: Here we report that Ror2 also positively modulates Wnt3a-activated canonical signaling in a lung carcinoma, H441 cell line. This activity of Ror2 is dependent on cooperative interactions with Fzd2 but not Fzd7. In addition, Ror2-mediated enhancement of canonical signaling requires the extracellular CRD, but not the intracellular PRD domain of Ror2. We further provide evidence that the positive effect of Ror2 on canonical Wnt signaling is inhibited by Dkk1 and Krm1 suggesting that Ror2 enhances an Lrp-dependent STF response. CONCLUSION: The current study demonstrates the function of Ror2 in modulating canonical Wnt signaling. These findings support a functional scheme whereby regulation of Wnt signaling is achieved by cooperative functions of multiple mediators.

SMAD3 prevents binding of NKX2.1 and FOXA1 to the SpB promoter through its MH1 and MH2 domains.

Mechanisms of gene repression by transforming growth factor-beta (TGF-beta) are not well understood. TGF-beta represses transcription of pulmonary surfactant protein-B gene in lung epithelial cells. Repression is mediated by SMAD3 through interactions with NKX2.1 and FOXA1, two key transcription factors that are positive regulators of SpB transcription. In this study, we found that SMAD3 interacts through its MAD domains, MH1 and MH2 with NKX2.1 and FOXA1 proteins. The sites of interaction on NKX2.1 are located within the NH2 and COOH domains, known to be involved in transactivation function. In comparison, weaker interaction of FOXA1 winged helix, and the NH(2)-terminal domains was documented with SMAD3. Both in vitro studies and in vivo ChIP assays show that interaction of SMAD3 MH1 and MH2 domains with NKX2.1 and FOXA1 results in reduced binding of NKX2.1 and FOXA1 to their cognate DNA-binding sites, and diminished promoter occupancy within the SpB promoter. Thus, these studies reveal for the first time a mechanism of TGF-beta-induced SpB gene repression that involves interactions between specific SMAD3 domains and the corresponding functional sites on NKX2.1 and FOXA1 transcription factors.

Physical and functional interactions between homeodomain NKX2.1 and winged helix/forkhead FOXA1 in lung epithelial cells.

NKX2.1 is a homeodomain transcription factor that controls development of the brain, lung, and thyroid. In the lung, Nkx2.1 is expressed in a proximo-distal gradient and activates specific genes in phenotypically distinct epithelial cells located along this axis. The mechanisms by which NKX2.1 controls its target genes may involve interactions with other transcription factors. We examined whether NKX2.1 interacts with members of the winged-helix/forkhead family of FOXA transcription factors to regulate two spatially and cell type-specific genes, SpC and Ccsp. The results show that NKX2.1 interacts physically and functionally with FOXA1. The nature of the interaction is inhibitory and occurs through the NKX2.1 homeodomain in a DNA-independent manner. On SpC, which lacks a FOXA1 binding site, FOXA1 attenuates NKX2.1-dependent transcription. Inhibition of FOXA1 by small interfering RNA increased SpC mRNA, demonstrating the in vivo relevance of this finding. In contrast, FOXA1 and NKX2.1 additively activate transcription from Ccsp, which includes both NKX2.1 and FOXA1 binding sites. In electrophoretic mobility shift assays, the GST-FOXA1 fusion protein interferes with the formation of NKX2.1 transcriptional complexes by potentially masking the latter's homeodomain DNA binding function. These findings suggest a novel mode of selective gene regulation by proximo-distal gradient distribution of and functional interactions between forkhead and homeodomain transcription factors.

Wnt5a regulates Shh and Fgf10 signaling during lung development.

The role of WNT signaling and its interactions with other morphogenetic pathways were investigated during lung development. Previously, we showed that targeted disruption of Wnt5a results in over-branching of the epithelium and thickening of the interstitium in embryonic lungs. In this study, we generated and characterized transgenic mice with lung-specific over-expression of Wnt5a from the SpC promoter. Over-expression of Wnt5a interfered with normal epithelial-mesenchymal interactions resulting in reduced epithelial branching and dilated distal airways. During early lung development, over-expression of Wnt5a in the epithelium resulted in increased Fgf10 in the mesenchyme and decreased Shh in the epithelium. Both levels and distribution of SHH receptor, Ptc were reduced in SpC-Wnt5a transgenic lungs and were reciprocally correlated to changes of Fgf10 in the mesenchyme, suggesting that SHH signaling is decreased by over-expression of Wnt5a. Cultured mesenchyme-free epithelial explants from SpC-Wnt5a transgenic lungs responded abnormally to recombinant FGF10 supplied uniformly in the Matrigel with dilated branch tips that mimic the in vivo phenotype. In contrast, chemotaxis of transgenic epithelial explants towards a directional FGF10 source was inhibited. These suggest that over-expression of Wnt5a disrupts epithelial-response to FGF10. In conclusion, Wnt5a regulates SHH and FGF10 signaling during lung development.