Hes6 acts in a positive feedback loop with the neurogenins to promote neuronal differentiation

During the development of the vertebrate nervous system, neurogenesis is promoted by proneural bHLH proteins such as the neurogenins, which act as potent transcriptional activators of neuronal differentiation genes. The pattern by which these proteins promote neuronal differentiation is thought to be governed by inhibitors, including a class of transcriptional repressors called the WRPW-bHLH proteins, which are similar to Drosophila proteins encoded by hairy and genes in the enhancer of split complex (E-(SPL)-C). Here, we describe the isolation and characterization of Hes6, which encodes a novel WRPW-bHLH protein expressed during neurogenesis in mouse and Xenopus embryos. We show that Hes6 expression follows that of neurogenins but precedes that of the neuronal differentiation genes. We provide several lines of evidence to show that Hes6 expression occurs in developing neurons and is induced by the proneural bHLH proteins but not by the Notch pathway. When ectopically expressed in Xenopus embryos, Hes6 promotes neurogenesis. The properties of Hes6 distinguish it from other members of the WRPW-bHLH family in vertebrates, and suggest that it acts in a positive-feedback loop with the proneural bHLH proteins to promote neuronal differentiation

Two-stage sinus floor augmentation using carbonate apatite

Purpose: The purpose of this study was to elucidate the efficacy and safety of carbonate apatite (CO3Ap) granules in 2-stage sinus floor augmentation through the radiographic and histomorphometric assessment of bone biopsy specimens. Methods: Two-stage sinus floor augmentation was performed on 13 patients with a total of 17 implants. Radiographic assessment using panoramic radiographs was performed immediately after augmentation and was also performed 2 additional times, at 7±2 months and 18±2 months post-augmentation, respectively. Bone biopsy specimens taken from planned implant placement sites underwent micro-computed tomography, after which histological sections were prepared. Results: Postoperative healing of the sinus floor augmentation was uneventful in all cases. The mean preoperative residual bone height was 3.5±1.3 mm, and this was increased to 13.3±1.7 mm by augmentation with the CO3Ap granules. The mean height of the augmented site had decreased to 10.7±1.9 mm by 7±2 months after augmentation; however, implants with lengths in the range of 6.5 to 11.5 mm could still be placed. The mean height of the augmented site had decreased to 9.6±1.4 mm by 18±2 months post-augmentation. No implant failure or complications were observed. Few inflammatory cells or foreign body giant cells were observed in the bone biopsy specimens. Although there were individual differences in the amount of new bone detected, new bone was observed to be in direct contact with the CO3Ap granules in all cases, without an intermediate layer of fibrous tissue. The amounts of bone and residual CO3Ap were 33.8%±15.1% and 15.3%±11.9%, respectively. Conclusions: In this first demonstration, low-crystalline CO3Ap granules showed excellent biocompatibility, and bone biopsy showed them to be replaced with bone in humans. CO3Ap granules are a useful and safe bone substitute for two-stage sinus floor augmentation

Magnetotransport Measurements of η-Mo_4O_<11> Crystals Using a Hybrid Magnet(Transport and Fermiology)

Magnetoresistance and Hall effect have been measured at 4.2 K using a hybrid magnet up to 26 T for several crystals of quasi-two-dimensional η-Mo_4O_ that has a charge-density-wave (CDW) induced nested multiple carrier band structure. The magnetoresistance is exceptionally large and the Hall resistivity shows a unique magnetic field dependence. We have confirmed the existence of characteristic hysteresis phenomena in both quantities when a field-sweep range exceeds a threshold value (?10 T). The hysteresis effects can be related with an effective and magnetic field dependent irreversible process for the CDW formation and destruction. We have also found that the hysteresis and quantum oscillations in the magnetotransport are strongly sample-dependent

Is the Importance of Achieving Stable Disease Different between Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors and Cytotoxic Agents in the Second-Line Setting for Advanced Non-small Cell Lung Cancer?

BackgroundIt is controversial whether achieving stable disease leads to a survival benefit and whether the importance of achieving stable disease differs between cytotoxic agents and molecular targeted agents. To examine these questions, the authors retrospectively reviewed phase II and III studies in the second-line setting for advanced non-small cell lung cancer using epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) and cytotoxic agents separately.MethodsThe authors chose 45 trials for the chemotherapy group and nine for the EGFR TKI group by searching the PubMed database. All nine trials in the EGFR TKI group concern gefitinib and erlotinib.ResultsThe median survival time increased 0.0375 month with each 1% increase in stable disease rate (p = 0.039), and each 1% increase in response rate resulted in 0.0744 (p < 0.001) month of median survival time in the analysis combined with both cytotoxic agents and EGFR TKIs. Main and interaction terms for EGFR TKI treatment were not statistically significant. With respect to time to progression, only response rate showed a statistically significant relationship with survival.ConclusionsTo obtain response seems to be more important than to achieve stable disease for both cytotoxic agents and EGFR TKIs, although achieving stable disease is still valuable. The relationship between survival and response or stable disease appears similar for cytotoxic agents and EGFR TKIs

Neonatal skin dysbiosis to infantile atopic dermatitis: Mitigating effects of skin care

Aoyama R., Nakagawa S., Ichikawa Y., et al. Neonatal skin dysbiosis to infantile atopic dermatitis: Mitigating effects of skin care. Allergy: European Journal of Allergy and Clinical Immunology , (2024); https://doi.org/10.1111/all.16095

VEZF1 elements mediate protection from DNA methylation

There is growing consensus that genome organization and long-range gene regulation involves partitioning of the genome into domains of distinct epigenetic chromatin states. Chromatin insulator or barrier elements are key components of these processes as they can establish boundaries between chromatin states. The ability of elements such as the paradigm &#946;-globin HS4 insulator to block the range of enhancers or the spread of repressive histone modifications is well established. Here we have addressed the hypothesis that a barrier element in vertebrates should be capable of defending a gene from silencing by DNA methylation. Using an established stable reporter gene system, we find that HS4 acts specifically to protect a gene promoter from de novo DNA methylation. Notably, protection from methylation can occur in the absence of histone acetylation or transcription. There is a division of labor at HS4; the sequences that mediate protection from methylation are separable from those that mediate CTCF-dependent enhancer blocking and USF-dependent histone modification recruitment. The zinc finger protein VEZF1 was purified as the factor that specifically interacts with the methylation protection elements. VEZF1 is a candidate CpG island protection factor as the G-rich sequences bound by VEZF1 are frequently found at CpG island promoters. Indeed, we show that VEZF1 elements are sufficient to mediate demethylation and protection of the APRT CpG island promoter from DNA methylation. We propose that many barrier elements in vertebrates will prevent DNA methylation in addition to blocking the propagation of repressive histone modifications, as either process is sufficient to direct the establishment of an epigenetically stable silent chromatin stat

Cyclin D1 promotes neurogenesis in the developing spinal cord in a cell cycle-independent manner

Neural stem and progenitor cells undergo an important transition from proliferation to differentiation in the G1 phase of the cell cycle. The mechanisms coordinating this transition are incompletely understood. Cyclin D proteins promote proliferation in G1 and typically are down-regulated before differentiation. Here we show that motoneuron progenitors in the embryonic spinal cord persistently express Cyclin D1 during the initial phase of differentiation, while down-regulating Cyclin D2. Loss-of-function and gain-offunction experiments indicate that Cyclin D1 (but not D2) promotes neurogenesis in vivo, a role that can be dissociated from its cell cycle function. Moreover, reexpression of Cyclin D1 can restore neurogenic capacity to D2-expressing glial-restricted progenitors. The neurogenic function of Cyclin D1 appears to be mediated, directly or indirectly, by Hes6, a proneurogenic basic helic-loop-helix transcription factor. These data identify a cell cycle-independent function for Cyclin D1 in promoting neuronal differentiation, along with a potential genetic pathway through which this function is exerted

Transient expression of Ngn3 in Xenopus endoderm promotes early and ectopic development of pancreatic beta and delta cells

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in genesis 50 (2012): 271-285, doi:10.1002/dvg.20828.Promoting ectopic development of pancreatic beta cells from other cell types is one of the strategies being pursued for the treatment of diabetes. To achieve this, a detailed outline of the molecular lineage that operates in pancreatic progenitor cells to generate beta cells over other endocrine cell types is necessary. Here, we demonstrate that early transient expression of the endocrine progenitor bHLH protein Neurogenin 3 (Ngn3) favors the promotion of pancreatic beta and delta cell fates over an alpha cell fate, while later transient expression promotes ectopic development of all three endocrine cell fates. We found that short-term activation of Ngn3 in Xenopus laevis endoderm just after gastrulation was sufficient to promote both early and ectopic development of beta and delta cells. By examining gene expression changes four hours after Ngn3 activation we identified several new downstream targets of Ngn3. We show that several of these are required for the promotion of ectopic beta cells by Ngn3 as well as for normal beta cell development. These results provide new detail regarding the Ngn3 transcriptional network operating in endocrine progenitor cells to specify a beta cell phenotype and should help define new approaches to promote ectopic development of beta cells for diabetes therapy.National Institutes of Health (DK077197