Glutamate signaling mediates C. elegans behavioral plasticity to pathogens.

In Caenorhabditis elegans, sensory neurons mediate behavioral response to pathogens. However, how C. elegans intergrades these sensory signals via downstream neuronal and molecular networks remains largely unknown. Here, we report that glutamate transmission mediates behavioral plasticity to Pseudomonas aeruginosa. Deletion in VGLUT/eat-4 renders the mutant animals unable to elicit either an attractive or an aversive preference to a lawn of P. aeruginosa. AMPA-type glutamate receptor GLR-1 promotes the avoidance response to P. aeruginosa. SOD-1 acts downstream of GLR-1 in the cholinergic motor neurons. SOD-1 forms a punctate structure and is localized next to GLR-1 at the ventral nerve cord. Finally, single-copy ALS-causative sod-1 point mutation acts as a loss-of-function allele in both pathogen avoidance and glr-1 dependent phenotypes. Our data showed a link between glutamate signaling and redox homeostasis in C. elegans pathogen response and may provide potential insights into the pathology triggered by oxidative stress in the nervous system.

Research on Diagnosis Architecture of Cardiovascular Diseases Based on Multimedical Images.

OBJECTIVE: To study the effect of a multi-image source 3D modeling imaging examination system on the diagnosis of cardiovascular diseases in cardiac surgery. METHODS: The data of 680 confirmed patients and 1590 suspected patients in the cardiac surgery department of all hospitals of a large chain hospital management group were selected. All patients gave the examination results of multiple image sources and independent examination results of multiple image sources, respectively, their examination sensitivity, specificity, and reliability were compared, and the treatment efficiency and nursing satisfaction of the virtual reference group were deduced in MATLAB. Perform the bivariate t-test and comparative statistics in SPSS. RESULTS: The multi-image source 3D modeling examination system had higher examination sensitivity, specificity, and reliability and higher examination sensitivity in the early stage of the disease. It was deduced that the clinical efficiency and nursing satisfaction based on the examination results were significantly improved (t < 10.000, p < 0.01). CONCLUSION: The multi-image source 3D modeling imaging examination system is suitable for the diagnosis of cardiovascular diseases in cardiac surgery.

[Color characterization and its correlation with quality index during ripening of Rubus chingii].

The color of Rubus chingii was characterized by digital method, and the content of water extract, alcohol extract, total flavonoids, total polysaccharides, total polyphenols, ellagic acid, linden glycoside, kaophenol-3-O-rutin were determined. Correlation regression was used to analyze the correlation between color and composition. The results showed that L~* was positively correlated with total polyphenols, kaophenol-3-O-rutin and tilide, and moderately positively correlated with total flavones, ellagic acid and aqueous extracts. The a~* value was negatively correlated with total polyphenols, kaophenol-3-O-rutin, and linden glycosides, while was moderately correlated with total flavones, aqueous extracts, and ellagic acid. The b~* value was negatively correlated with the water extract, and moderately correlated with the content of total polyphenols, total polysaccharides, alcohol extract and kaophenol-3-O-rutin, which showed that R. chingii mature color had a significant correlation with material composition in the process of dynamic change. According to the law of dynamic change in the color and quality indexes, it is determined that the appropriate harvest time is in late April to May 1, while the fruit is not turn yellow. The agronomic traits related to fruit was(12.49±0.56) mm in diameter,(14.25±1.19)mm in height,(1.20±0.14) g in weight, the chroma L~* value was 52.87±3.14,a~* value was 2.01±1.58, b~* values was 28.31±3.88. The results lay a foundation for establishing an objective quantitative evaluation model of R. chingii color from experience.

Clinical value of TV-CDS combined with serum tumor markers in diagnosis of ovarian cancer.

Clinical application value was investigated of transvaginal color Doppler ultrasound (TV-CDS) combined with serum tumor markers carbohydrate antigen 125 (CA125), vascular endothelial growth factor (VEGF) and osteopontin (OPN) in the diagnosis of ovarian cancer (OC). One hundred and six patients with OC [malignant tumor group (MTG)] and fifty patients with benign ovarian diseases [benign control group (BCG)] were selected. Both groups of patients underwent TV-CDS examination. The lesion morphology and internal structure were observed, and the tumor blood flow signal, resistance index (RI) and pulsability index (PI) under ultrasound were determined. Serum CA125 was detected by electrochemiluminescence, and VEGF and OPN levels were detected by enzyme-linked immunosorbent assay. The incidence of irregular lesion morphology, unclear boundary, uneven internal echo, microcalcification and side-acoustic images in OC group (OCG) was significantly higher than that in BCG (P<0.01). As for blood flow grading, most patients in the MTG were in grade II and III, while most patients in the BCG were in grade 0. Compared with BCG, the flow RI and PI in the OCG were significantly reduced (P<0.01). The levels of serum CA125, VEGF and OPN in OCG were significantly higher than those in BCG. The expression levels of serum CA125, VEGF and OPN in OC patients with clinical high stage (stage III and IV), poorly differentiated, ascites, recurrence and metastasis were significantly higher than those in patients with clinical low stage (stage I and II), well differentiated, no ascites and no recurrence and metastasis (P<0.05). With the disappearance of the tumor or the decrease of tumor load, the serum marker levels after treatment were significantly lower than that before treatment (P<0.05). The sensitivity and accuracy of the combined examination in the diagnosis of OC were obviously improved compared with the single and partial combined examinations (P<0.05). In conclusion, combined examination can significantly improve the sensitivity and accuracy of OC, which is conducive to early diagnosis and clinical intervention of OC.

Engineering Genetic Predisposition in Human Neuroepithelial Stem Cells Recapitulates Medulloblastoma Tumorigenesis.

Human neural stem cell cultures provide progenitor cells that are potential cells of origin for brain cancers. However, the extent to which genetic predisposition to tumor formation can be faithfully captured in stem cell lines is uncertain. Here, we evaluated neuroepithelial stem (NES) cells, representative of cerebellar progenitors. We transduced NES cells with MYCN, observing medulloblastoma upon orthotopic implantation in mice. Significantly, transcriptomes and patterns of DNA methylation from xenograft tumors were globally more representative of human medulloblastoma compared to a MYCN-driven genetically engineered mouse model. Orthotopic transplantation of NES cells generated from Gorlin syndrome patients, who are predisposed to medulloblastoma due to germline-mutated PTCH1, also generated medulloblastoma. We engineered candidate cooperating mutations in Gorlin NES cells, with mutation of DDX3X or loss of GSE1 both accelerating tumorigenesis. These findings demonstrate that human NES cells provide a potent experimental resource for dissecting genetic causation in medulloblastoma.

The emerging roles and functions of circular RNAs and their generation.

Circular RNAs (circRNAs) are closed long non-coding RNAs, in which the 5' and 3' termini are covalently linked by back-splicing of exons from a single pre-mRNA. Emerging evidence indicates that circRNAs are broadly expressed in mammalian cells and show cell type- or tissue-specific expression patterns. Importantly, circRNAs have been shown to participate in regulating various biological processes. Functionally, circRNAs can influence cellular physiology through various molecular mechanisms, such as serving as a decoy for microRNAs or RNA-binding proteins to modulate gene expression or translation of regulatory proteins. The biogenesis of circRNAs is known to be tightly regulated by cis- (intronic complementary sequences) and/or trans-factors (splicing factors) that constitute a cell- and context-dependent regulatory layer in the control of gene expression. However, our understanding of the regulation and function of circRNAs is still limited. In this review, we summarize the current progress in elucidating the functional roles, mechanisms and biogenesis of circRNAs. We also discuss the relationship between regulation and formation of circRNAs.

Modeling spinocerebellar ataxias 2 and 3 with iPSCs reveals a role for glutamate in disease pathology.

Spinocerebellar ataxias 2 and 3 (SCA2 and SCA3) are dominantly inherited neurodegenerative diseases caused by expansion of polyglutamine-encoding CAG repeats in the affected genes. The etiology of these disorders is known to involve widespread loss of neuronal cells in the cerebellum, however, the mechanisms that contribute to cell death are still elusive. Here we established SCA2 and SCA3 induced pluripotent stem cells (iPSCs) and demonstrated that SCA-associated pathological features can be recapitulated in SCA-iPSC-derived neurons. Importantly, our results also revealed that glutamate stimulation promotes the development of disease-related phenotypes in SCA-iPSC-derived neurons, including altered composition of glutamatergic receptors, destabilized intracellular calcium, and eventual cell death. Furthermore, anti-glutamate drugs and calcium stabilizer treatment protected the SCA-iPSC-derived neurons and reduced cell death. Collectively, our study demonstrates that the SCA-iPSC-derived neurons can recapitulate SCA-associated pathological features, providing a valuable tool to explore SCA pathogenic mechanisms and screen drugs to identify potential SCA therapeutics.

Trans-spliced long non-coding RNA: an emerging regulator of pluripotency.

With dual capacities for unlimited self-renewal and pluripotent differentiation, pluripotent stem cells (PSCs) give rise to many cell types in our body and PSC culture systems provide an unparalleled opportunity to study early human development and disease. Accumulating evidence indicates that the molecular mechanisms underlying pluripotency maintenance in PSCs involve many factors. Among these regulators, recent studies have shown that long non-coding RNAs (lncRNAs) can affect the pluripotency circuitry by cooperating with master pluripotency-associated factors. Additionally, trans-spliced RNAs, which are generated by combining two or more pre-mRNA transcripts to produce a chimeric RNA, have been identified as regulators of various biological processes, including human pluripotency. In this review, we summarize and discuss current knowledge about the roles of lncRNAs, including trans-spliced lncRNAs, in controlling pluripotency.

Intracellular biosynthesis of lipids and cholesterol by Scap and Insig in mesenchymal cells regulates long bone growth and chondrocyte homeostasis.

During enchondral ossification, mesenchymal cells express genes regulating the intracellular biosynthesis of cholesterol and lipids. Here, we have investigated conditional deletion of Scap or of Insig1 and Insig2 (Scap inhibits intracellular biosynthesis and Insig proteins activate intracellular biosynthesis). Mesenchymal condensation and chondrogenesis was disrupted in mice lacking Scap in mesenchymal progenitors, whereas mice lacking the Insig genes in mesenchymal progenitors had short limbs, but normal chondrogenesis. Mice lacking Scap in chondrocytes showed severe dwarfism, with ectopic hypertrophic cells, whereas deletion of Insig genes in chondrocytes caused a mild dwarfism and shortening of the hypertrophic zone. In vitro studies showed that intracellular cholesterol in chondrocytes can derive from exogenous and endogenous sources, but that exogenous sources cannot completely overcome the phenotypic effect of Scap deficiency. Genes encoding cholesterol biosynthetic proteins are regulated by Hedgehog (Hh) signaling, and Hh signaling is also regulated by intracellular cholesterol in chondrocytes, suggesting a feedback loop in chondrocyte differentiation. Precise regulation of intracellular biosynthesis is required for chondrocyte homeostasis and long bone growth, and these data support pharmacological modulation of cholesterol biosynthesis as a therapy for select cartilage pathologies.

The circular RNA circBIRC6 participates in the molecular circuitry controlling human pluripotency.

Accumulating evidence indicates that circular RNAs (circRNAs) are abundant in the human transcriptome. However, their involvement in biological processes, including pluripotency, remains mostly undescribed. We identified a subset of circRNAs that are enriched in undifferentiated human embryonic stem cells (hESCs) and demonstrated that two, circBIRC6 and circCORO1C, are functionally associated with the pluripotent state. Mechanistically, we found that circBIRC6 is enriched in the AGO2 complex and directly interacts with microRNAs, miR-34a, and miR-145, which are known to modulate target genes that maintain pluripotency. Correspondingly, circBIRC6 attenuates the downregulation of these target genes and suppresses hESC differentiation. We further identified hESC-enriched splicing factors (SFs) and demonstrated that circBIRC6 biogenesis in hESCs is promoted by the SF ESRP1, whose expression is controlled by the core pluripotency-associated factors, OCT4 and NANOG. Collectively, our data suggest that circRNA serves as a microRNA "sponge" to regulate the molecular circuitry, which modulates human pluripotency and differentiation.

Galectin-8 regulates targeting of Gp135/podocalyxin and lumen formation at the apical surface of renal epithelial cells.

Establishment of apical-basal polarity, through correct targeting of polarity determinants to distinct domains of the plasma membrane, is a fundamental process for the development of functioning epithelial tubules. Here we report that galectin (Gal)-8 regulates apical-basal polarity of Madin-Darby canine kidney (MDCK) cells via apical targeting of 135-kDa glycoprotein (Gp135). Gal-8 interacts with newly synthesized Gp135 in a glycan-dependent manner. Gal-8 knockdown induces aberrant lumens at the lateral domain and mistargeting of Gp135 to this structure, thus disrupting the kidney epithelial polarity of MDCK cells, which organize lumens at the apical surface. The O-glycosylation deletion mutant of Gp135 phenocopies the effect of Gal-8 knockdown, which suggests that Gal-8 is the decoding machinery for the apical sorting signals of Gp135 residing at its O-glycosylation-rich region. Collectively, our results reveal a new role of Gal-8 in the development of luminal organs by regulating targeting of apical polarity protein Gp135.-Lim, H., Yu, C.-Y., Jou, T.-S. Galectin-8 regulates targeting of Gp135/podocalyxin and lumen formation at the apical surface of renal epithelial cells.

The Trans-Spliced Long Noncoding RNA tsRMST Impedes Human Embryonic Stem Cell Differentiation Through WNT5A-Mediated Inhibition of the Epithelial-to-Mesenchymal Transition.

The trans-spliced noncoding RNA RMST (tsRMST) is an emerging regulatory lncRNA in the human pluripotency circuit. Previously, we found that tsRMST represses lineage-specific transcription factors through the PRC2 complex and NANOG in human pluripotent stem cells (hESCs). Here, we demonstrate that tsRMST also modulates noncanonical Wnt signaling to suppress the epithelial-to-mesenchymal transition (EMT) and in vitro differentiation of embryonic stem cells (ESCs). Our results demonstrate that disruption of tsRMST expression in hESCs results in the upregulation of WNT5A, EMT, and lineage-specific genes/markers. Furthermore, we found that the PKC inhibitors Go6983 and Go6976 inhibited the effects of WNT5A, indicating that WNT5A promotes the EMT and in vitro differentiation although conventional and novel PKC activation in hESCs. Finally, we showed that either antiserum neutralization of WNT5A or Go6983 treatment in tsRMST knockdown cells decreased the expression of mesenchymal and lineage-specific markers. Together, these findings indicate that tsRMST regulates Wnt and EMT signaling pathways in hESCs by repressing WNT5A, which is a potential EMT inducer for promoting in vitro differentiation of hESCs through PKC activation. Our findings provide further insights into the role of trans-spliced RNA and WNT5A in hESC differentiation, in which EMT plays an important role. Stem Cells 2016;34:2052-2062.

Hedgehog inhibits ß-catenin activity in synovial joint development and osteoarthritis.

Both the WNT/ß-catenin and hedgehog signaling pathways are important in the regulation of limb development, chondrocyte differentiation, and degeneration of articular cartilage in osteoarthritis (OA). It is not clear how these signaling pathways interact in interzone cell differentiation and synovial joint morphogenesis. Here, we determined that constitutive activation of hedgehog signaling specifically within interzone cells induces joint morphological changes by selectively inhibiting ß-catenin-induced Fgf18 expression. Stabilization of ß-catenin or treatment with FGF18 rescued hedgehog-induced phenotypes. Hedgehog signaling induced expression of a dominant negative isoform of TCF7L2 (dnTCF7L2) in interzone progeny, which may account for the selective regulation of ß-catenin target genes observed. Knockdown of TCF7L2 isoforms in mouse chondrocytes rescued hedgehog signaling-induced Fgf18 downregulation, while overexpression of the human dnTCF7L2 orthologue (dnTCF4) in human chondrocytes promoted the expression of catabolic enzymes associated with OA. Similarly, expression of dnTCF4 in human chondrocytes positively correlated with the aggrecanase ADAMTS4. Consistent with our developmental findings, activation of ß-catenin also attenuated hedgehog-induced or surgically induced articular cartilage degeneration in mouse models of OA. Thus, our results demonstrate that hedgehog inhibits selective ß-catenin target gene expression to direct interzone progeny fates and articular cartilage development and disease. Moreover, agents that increase ß-catenin activity have the potential to therapeutically attenuate articular cartilage degeneration as part of OA.

Granulosa cell-derived induced pluripotent stem cells exhibit pro-trophoblastic differentiation potential.

INTRODUCTION: Human induced pluripotent stem cells (hiPSCs) have been derived from various somatic cell types. Granulosa cells, a group of cells which surround oocytes and are obtained from the (normally discarded) retrieved egg follicles of women undergoing infertility treatment, are a possible cell source for induced pluripotent stem cell (iPSC) generation. Here, we explored the possibility of using human granulosa cells as a donor cell type for iPSC reprogramming, and compared granulosa cell-derived iPSCs (iGRAs) with those derived from other cell sources, to determine the potential ability of iGRA differentiation. METHODS: Granulosa cells were collected from egg follicles retrieved from women undergoing infertility treatment. After short-term culture, the granulosa cells derived from different patients were mixed in culture, and infected with retroviruses encoding reprogramming factors. The resulting iPSC clones were selected and subjected to microsatellite DNA analysis to determine their parental origin. IGRAs were subjected to RT-PCR, immunofluorescence staining, and in vitro and in vivo differentiation assays to further establish their pluripotent characteristics. RESULTS: Microsatellite DNA analysis was used to demonstrate that hiPSCs with different parental origins can be simultaneously reprogrammed by retroviral transfection of a mixed human granulosa cell population obtained from multiple individuals. The iGRAs resemble human embryonic stem cells (hESCs) in many respects, including morphological traits, growth requirements, gene and marker expression profiles, and in vitro and in vivo developmental propensities. We also demonstrate that the iGRAs express low levels of NLRP2, and differentiating iGRAs possess a biased differentiation potential toward the trophoblastic lineage. Although NLRP2 knockdown in hESCs promotes trophoblastic differentiation of differentiating hESCs, it does not result in exit from pluripotency. These results imply that NLRP2 may play a role in regulating the trophoblastic differentiation of human pluripotent stem cells. CONCLUSIONS: These findings provide a means of generating iPSCs from multiple granulosa cell populations with different parental origins. The ability to generate iPSCs from granulosa cells not only enables modeling of infertility-associated disease, but also provides a means of identifying potential clinical interventions through iPSC-based drug screening.

Characteristic expression of major histocompatibility complex and immune privilege genes in human pluripotent stem cells and their derivatives.

Pluripotent stem cells, including human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs), have been regarded as useful sources for cell-based transplantation therapy. However, immunogenicity of the cells remains the major determinant for successful clinical application. We report the examination of several hESC lines (NTU1 and H9), hiPSC lines, and their derivatives (including stem cell-derived hepatocytes) for the expression of major histocompatibility complex (MHC), natural killer (NK) cell receptor (NKp30, NKp44, NKp46) ligand, immune-related genes, human leukocyte antigen (HLA) haplotyping, and the effects in functional mixed lymphocyte reaction (MLR). Flow cytometry showed lower levels (percentages and fluorescence intensities) of MHC class I (MHC-I) molecules, ß2-microglobulin, and HLA-E in undifferentiated stem cells. The levels were increased after cotreatment with interferon-γ and/or in vitro differentiation. Antigen-presenting cell markers (CD11c, CD80, and CD86) and MHC-II (HLA-DP, -DQ, and -DR) remained low throughout the treatments. Recognition of stem cells/derivatives by NK lysis receptors were lower or absent. Activation of responder lymphocytes was significantly lower by undifferentiated stem cells than by allogeneic lymphocytes in MLR, but differentiated NTU1 hESCs induced a cell number-dependent lymphocyte proliferation comparable with that by allogeneic lymphocytes. Interestingly, activation of lymphocytes by differentiated hiPSCs or H9 cells became blunted at higher cell numbers. Real-time reverse transcriptase PCR (RT-PCR) showed significant differential expression of immune privilege genes (TGF-ß2, Arginase 2, Indole 1, GATA3, POMC, VIP, CALCA, CALCB, IL-1RN, CD95L, CR1L, Serpine 1, HMOX1, IL6, LGALS3, HEBP1, THBS1, CD59, and LGALS1) in pluripotent stem cells/derivatives when compared to somatic cells. It was concluded that pluripotent stem cells/derivatives are predicted to be immunogenic, though evidence suggests some level of potential immune privilege. In addition, differential immunogenicity may exist between different pluripotent stem cell lines and their derivatives.

Is an observed non-co-linear RNA product spliced in trans, in cis or just in vitro?

Global transcriptome investigations often result in the detection of an enormous number of transcripts composed of non-co-linear sequence fragments. Such 'aberrant' transcript products may arise from post-transcriptional events or genetic rearrangements, or may otherwise be false positives (sequencing/alignment errors or in vitro artifacts). Moreover, post-transcriptionally non-co-linear ('PtNcl') transcripts can arise from trans-splicing or back-splicing in cis (to generate so-called 'circular RNA'). Here, we collected previously-predicted human non-co-linear RNA candidates, and designed a validation procedure integrating in silico filters with multiple experimental validation steps to examine their authenticity. We showed that >50% of the tested candidates were in vitro artifacts, even though some had been previously validated by RT-PCR. After excluding the possibility of genetic rearrangements, we distinguished between trans-spliced and circular RNAs, and confirmed that these two splicing forms can share the same non-co-linear junction. Importantly, the experimentally-confirmed PtNcl RNA events and their corresponding PtNcl splicing types (i.e. trans-splicing, circular RNA, or both sharing the same junction) were all expressed in rhesus macaque, and some were even expressed in mouse. Our study thus describes an essential procedure for confirming PtNcl transcripts, and provides further insight into the evolutionary role of PtNcl RNA events, opening up this important, but understudied, class of post-transcriptional events for comprehensive characterization.

Integrative transcriptome sequencing identifies trans-splicing events with important roles in human embryonic stem cell pluripotency.

Trans-splicing is a post-transcriptional event that joins exons from separate pre-mRNAs. Detection of trans-splicing is usually severely hampered by experimental artifacts and genetic rearrangements. Here, we develop a new computational pipeline, TSscan, which integrates different types of high-throughput long-/short-read transcriptome sequencing of different human embryonic stem cell (hESC) lines to effectively minimize false positives while detecting trans-splicing. Combining TSscan screening with multiple experimental validation steps revealed that most chimeric RNA products were platform-dependent experimental artifacts of RNA sequencing. We successfully identified and confirmed four trans-spliced RNAs, including the first reported trans-spliced large intergenic noncoding RNA ("tsRMST"). We showed that these trans-spliced RNAs were all highly expressed in human pluripotent stem cells and differentially expressed during hESC differentiation. Our results further indicated that tsRMST can contribute to pluripotency maintenance of hESCs by suppressing lineage-specific gene expression through the recruitment of NANOG and the PRC2 complex factor, SUZ12. Taken together, our findings provide important insights into the role of trans-splicing in pluripotency maintenance of hESCs and help to facilitate future studies into trans-splicing, opening up this important but understudied class of post-transcriptional events for comprehensive characterization.

Epithelial cell adhesion molecule (EpCAM) complex proteins promote transcription factor-mediated pluripotency reprogramming.

Epithelial cell adhesion molecule (EpCAM) is a transmembrane glycoprotein that is highly expressed in embryonic stem cells (ESCs) and its role in maintenance of pluripotency has been suggested previously. In epithelial cancer cells, activation of the EpCAM surface-to-nucleus signaling transduction pathway involves a number of membrane proteins. However, their role in somatic cell reprogramming is still unknown. Here we demonstrate that EpCAM and its associated protein, Cldn7, play a critical role in reprogramming. Quantitative RT-PCR analysis of Oct4, Sox2, Klf4, and c-Myc (OSKM) infected mouse embryonic fibroblasts (MEFs) indicated that EpCAM and Cldn7 were up-regulated during reprogramming. Analysis of numbers of alkaline phosphatase- and Nanog-positive clones, and the expression level of pluripotency-related genes demonstrated that inhibition of either EpCAM or Cldn7 expression resulted in impairment in reprogramming efficiency, whereas overexpression of EpCAM, EpCAM plus Cldn7, or EpCAM intercellular domain (EpICD) significantly enhanced reprogramming efficiency in MEFs. Furthermore, overexpression of EpCAM or EpICD significantly repressed the expression of p53 and p21 in the reprogramming MEFs, and both EpCAM and EpICD activated the promoter activity of Oct4. These observations suggest that EpCAM signaling may enhance reprogramming through up-regulation of Oct4 and possible suppression of the p53-p21 pathway. In vitro and in vivo characterization indicated that the EpCAM-reprogrammed iPSCs exhibited similar molecular and functional features to the mouse ESCs. In summary, our studies provide additional insight into the molecular mechanisms of reprogramming and suggest a more effective means of induced pluripotent stem cell generation.

Kif7 promotes hedgehog signaling in growth plate chondrocytes by restricting the inhibitory function of Sufu.

Proper regulation of Indian hedgehog (Ihh) signaling is vital for chondrocyte proliferation and differentiation in the growth plate. Its dysregulation causes skeletal dysplasia, osteoarthritis or cartilaginous neoplasia. Here, we show that Suppressor of fused (Sufu) and Kif7 are essential regulators of Ihh signaling. While Sufu acts as a negative regulator of Gli transcription factors, Kif7 functions both positively and negatively in chondrocytes. Kif7 plays a role in the turnover of Sufu and the exclusion of Sufu-Gli complexes from the primary cilium. Importantly, halving the dose of Sufu restores normal hedgehog pathway activity and chondrocyte development in Kif7-null mice, demonstrating that the positive role of Kif7 is to restrict the inhibitory activity of Sufu. Furthermore, Kif7 also inhibits Gli transcriptional activity in the chondrocytes when Sufu function is absent. Therefore, Kif7 regulates the activity of Gli transcription factors through both Sufu-dependent and -independent mechanisms.