Calcium dynamics at the neural cell primary cilium regulate Hedgehog signaling-dependent neurogenesis in the embryonic neural tube.

The balance between neural stem cell proliferation and neuronal differentiation is paramount for the appropriate development of the nervous system. Sonic hedgehog (Shh) is known to sequentially promote cell proliferation and specification of neuronal phenotypes, but the signaling mechanisms responsible for the developmental switch from mitogenic to neurogenic have remained unclear. Here, we show that Shh enhances Ca2+ activity at the neural cell primary cilium of developing Xenopus laevis embryos through Ca2+ influx via transient receptor potential cation channel subfamily C member 3 (TRPC3) and release from intracellular stores in a developmental stage-dependent manner. This ciliary Ca2+ activity in turn antagonizes canonical, proliferative Shh signaling in neural stem cells by down-regulating Sox2 expression and up-regulating expression of neurogenic genes, enabling neuronal differentiation. These discoveries indicate that the Shh-Ca2+-dependent switch in neural cell ciliary signaling triggers the switch in Shh action from canonical-mitogenic to neurogenic. The molecular mechanisms identified in this neurogenic signaling axis are potential targets for the treatment of brain tumors and neurodevelopmental disorders.

Folate receptor 1 is necessary for neural plate cell apical constriction during Xenopus neural tube formation.

Folate supplementation prevents up to 70% of neural tube defects (NTDs), which result from a failure of neural tube closure during embryogenesis. The elucidation of the mechanisms underlying folate action has been challenging. This study introduces Xenopus laevis as a model to determine the cellular and molecular mechanisms involved in folate action during neural tube formation. We show that knockdown of folate receptor 1 (Folr1; also known as FRα) impairs neural tube formation and leads to NTDs. Folr1 knockdown in neural plate cells only is necessary and sufficient to induce NTDs. Folr1-deficient neural plate cells fail to constrict, resulting in widening of the neural plate midline and defective neural tube closure. Pharmacological inhibition of folate action by methotrexate during neurulation induces NTDs by inhibiting folate interaction with its uptake systems. Our findings support a model in which the folate receptor interacts with cell adhesion molecules, thus regulating the apical cell membrane remodeling and cytoskeletal dynamics necessary for neural plate folding. Further studies in this organism could unveil novel cellular and molecular events mediated by folate and lead to new ways of preventing NTDs.

Noncanonical function of folate through folate receptor 1 during neural tube formation.

Folate supplementation reduces the occurrence of neural tube defects (NTDs), birth defects consisting in the failure of the neural tube to form and close. The mechanisms underlying NTDs and their prevention by folate remain unclear. Here we show that folate receptor 1 (FOLR1) is necessary for the formation of neural tube-like structures in human-cell derived neural organoids. FOLR1 knockdown in neural organoids and in Xenopus laevis embryos leads to NTDs that are rescued by pteroate, a folate precursor that is unable to participate in metabolism. We demonstrate that FOLR1 interacts with and opposes the function of CD2-associated protein, molecule essential for apical endocytosis and turnover of C-cadherin in neural plate cells. In addition, folates increase Ca2+ transient frequency, suggesting that folate and FOLR1 signal intracellularly to regulate neural plate folding. This study identifies a mechanism of action of folate distinct from its vitamin function during neural tube formation.

Non-canonical function of folate/folate receptor 1 during neural tube formation.

Folate supplementation reduces the occurrence of neural tube defects, one of the most common and serious birth defects, consisting in the failure of the neural tube to form and close early in pregnancy. The mechanisms underlying neural tube defects and folate action during neural tube formation remain unclear. Here we show that folate receptor 1 (FOLR1) is necessary for the formation of neural tube-like structures in human-cell derived neural organoids. Knockdown of FOLR1 in human neural organoids as well as in the Xenopus laevis in vivo model leads to neural tube defects that are rescued by pteroate, a folate precursor that binds to FOLR1 but is unable to participate in metabolic pathways. We demonstrate that FOLR1 interacts with and opposes the function of CD2-associated protein (CD2AP), a molecule that we find is essential for apical endocytosis and the spatiotemporal turnover of the cell adherens junction component C-cadherin in neural plate cells. The counteracting action of FOLR1 on these processes is mediated by regulating CD2AP protein level via a degradation-dependent mechanism. In addition, folate and pteroate increase Ca 2+ transient frequency in the neural plate in a FOLR1-dependent manner, suggesting that folate/FOLR1 signal intracellularly to regulate neural plate folding. This study identifies a mechanism of action of folate distinct from its vitamin function during neural tube formation.

Gastric cancer epidemiology from 2009 to 2019 in Dnipro Region, Ukraine.

BACKGROUND: Gastric cancer (GC) is in top-five the most frequent cancers in Ukrainian males and is the third cause of death among patients with cancer. GC keeps its leading position in cancer ranks despite the decline in incidence and mortality over the last 50 years. Local epidemiological information will help in better targeting medical and public health interventions. PATIENTS AND METHODS: The data about 8438 patients with newly diagnosed GC between 2009 and 2019 was obtained from Dnipro Cancer Registry. RESULTS: Incidence decreased from 24.5 to 22.6, mortality decreased from 21.4 to 15.7 (per 100000), death rate increased from 0.64 to 1.04 between 2009 and 2019. Over 11 years of observation incidence was 23.4, mortality was 19.4, death rate was 0.721. Standardised incidence ratio was 1.42, standardised mortality rate was 1.67; age-standardised incidence was 25.5, age-standardised mortality was 21.2 (European standard). Median (95% confidence interval (95% CI)) survival of the patients was 172 (165-178) days. One-year survival rate fluctuated between 27% and 34%. Male sex and older age were associated with higher risk of death (hazard ratio (95% CI) - 1.08 (1.03-1.13) vs females and 1.15 (1.12-1.17) per 10-years increase of age, respectively). CONCLUSIONS: The study describes the trends in epidemiology of gastric cancer in Dnipro region, Ukraine, between 2009 and 2019. The need for the national prevention strategy of GC in Ukraine was identified.

Non-canonical Hedgehog signaling regulates spinal cord and muscle regeneration in Xenopus laevis larvae.

Inducing regeneration in injured spinal cord represents one of modern medicine's greatest challenges. Research from a variety of model organisms indicates that Hedgehog (Hh) signaling may be a useful target to drive regeneration. However, the mechanisms of Hh signaling-mediated tissue regeneration remain unclear. Here, we examined Hh signaling during post-amputation tail regeneration in Xenopus laevis larvae. We found that while Smoothened (Smo) activity is essential for proper spinal cord and skeletal muscle regeneration, transcriptional activity of the canonical Hh effector Gli is repressed immediately following amputation, and inhibition of Gli1/2 expression or transcriptional activity has minimal effects on regeneration. In contrast, we demonstrate that protein kinase A is necessary for regeneration of both muscle and spinal cord, in concert with and independent of Smo, respectively, and that its downstream effector CREB is activated in spinal cord following amputation in a Smo-dependent manner. Our findings indicate that non-canonical mechanisms of Hh signaling are necessary for spinal cord and muscle regeneration.

Folate action in nervous system development and disease.

The vitamin folic acid has been recognized as a crucial environmental factor for nervous system development. From the early fetal stages of the formation of the presumptive spinal cord and brain to the maturation and maintenance of the nervous system during infancy and childhood, folate levels and its supplementation have been considered influential in the clinical outcome of infants and children affected by neurological diseases. Despite the vast epidemiological information recorded on folate function and neural tube defects, neural development and neurodegenerative diseases, the mechanisms of folate action in the developing neural tissue have remained elusive. Here we compiled studies that argue for a unique role for folate in nervous system development and function and its consequences to neural disease and repair. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 78: 391-402, 2018.

Spatiotemporal integration of developmental cues in neural development.

Nervous system development relies on the generation of neurons, their differentiation and establishment of synaptic connections. These events exhibit remarkable plasticity and are regulated by many developmental cues. Here, we review the mechanisms of three classes of these cues: morphogenetic proteins, electrical activity, and the environment. We focus on second messenger dynamics and their role as integrators of the action of diverse cues, enabling plasticity in the process of neural development.

Pegylated liposomal doxorubicin plus docetaxel significantly improves time to progression without additive cardiotoxicity compared with docetaxel monotherapy in patients with advanced breast cancer previously treated with neoadjuvant-adjuvant anthracycline therapy: results from a randomized phase III study.

PURPOSE: To determine whether the combination of pegylated liposomal doxorubicin (PLD) and docetaxel significantly prolongs time to disease progression compared with docetaxel alone without an increase in cardiac toxicity in women with advanced breast cancer who had experienced relapse at least 1 year after prior adjuvant or neoadjuvant anthracycline therapy. PATIENTS AND METHODS: This international, phase III study randomly assigned 751 patients to receive either docetaxel 75 mg/m(2) (n = 373) or PLD 30 mg/m(2) followed by docetaxel 60 mg/m(2) every 21 days (n = 378) and continued until disease progression or prohibitive toxicity. The primary end point was time to progression (TTP). Secondary end points were overall survival (OS), objective response rate (ORR), cardiac toxicity, and safety. RESULTS: Treatment with PLD-docetaxel significantly improved median TTP from 7.0 to 9.8 months (hazard ratio [HR] = 0.65; 95% CI, 0.55 to 0.77; P = .000001) and the ORR from 26% to 35% (P = .0085). OS was similar between the two groups (HR = 1.02; 95% CI, 0.86 to 1.22). The incidence of grade 3 or 4 adverse events were similar (78% v 72%), although a higher incidence of hand-foot syndrome (24% v 0%) and mucositis/stomatitis (12% v 1%) were observed in the PLD-docetaxel combination. Protocol-defined left ventricular ejection fraction decreases and congestive heart failure were reported in 5% and 1% in both treatment arms, respectively. CONCLUSION: The PLD-docetaxel combination was more effective than docetaxel alone in women with metastatic breast cancer who had experienced relapse at least 1 year after prior adjuvant anthracycline therapy without an increase in cardiac toxicity, although mucocutaneous toxicity was more common.