Neutrophil diversity is associated with T-cell immunity and clinical relevance in patients with thyroid cancer.

Neutrophil heterogeneity is involved in autoimmune diseases, sepsis, and several cancers. However, the link between neutrophil heterogeneity and T-cell immunity in thyroid cancer is incompletely understood. We investigated the circulating neutrophil heterogeneity in 3 undifferentiated thyroid cancer (UTC), 14 differentiated thyroid cancer (DTC) (4 Stage IV, 10 Stage I-II), and healthy controls (n = 10) by transcriptomic data and cytometry. Participants with UTC had a significantly higher proportion of immature high-density neutrophils (HDN) and lower proportion of mature HDN in peripheral blood compared to DTC. The proportion of circulating PD-L1+ immature neutrophils were significantly increased in advanced cancer patients. Unsupervised analysis of transcriptomics data from circulating HDN revealed downregulation of innate immune response and T-cell receptor signaling pathway in cancer patients. Moreover, UTC patients revealed the upregulation of glycolytic process and glutamate receptor signaling pathway. Comparative analysis across tumor types and stages revealed the downregulation of various T-cell-related pathways, such as T-cell receptor signaling pathway and T-cell proliferation in advanced cancer patients. Moreover, the proportions of CD8+ and CD4+ T effector memory CD45RA+ (TEMRA) cells from peripheral blood were significantly decreased in UTC patients compared to DTC patients. Finally, we demonstrated that proportions of tumor-infiltrated neutrophils were increased and related with poor prognosis in advanced thyroid cancer using data from our RNA-seq and TCGA (The Cancer Genome Atlas) data. In conclusion, observed prevalence of circulating immature high-density neutrophils and their immunosuppressive features in undifferentiated thyroid cancers underscore the importance of understanding neutrophil dynamics in the context of tumor progression in thyroid cancer.

Effects of a Web-based Weight Management Education Program on Various Factors for Overweight and Obese Women: Randomized Controlled Trial.

BACKGROUND: Mediated diet and exercise methods yield effective short-term weight loss but are costly and hard to manage. However, web-based programs can serve many participants, offering ease of access and cost-efficiency. OBJECTIVE: This study aimed to compare the effectiveness of a web-based weight management program through web-based education alone (MINE) or combined with tailored video feedback (MINE Plus) with a control (CO) group. METHODS: This intervention included 60 Korean women with overweight and obesity (BMI≥23 kg/m2) aged 19 years to 39 years old. We randomly allocated 60 participants to each of 3 groups: (1) MINE group (web-based education video and self-monitoring app), (2) MINE Plus group (web-based education video, self-monitoring app, and 1:1 tailored video feedback), and (3) CO group (only self-monitoring app). Web-based education included nutrition, physical activity, psychological factors, medical knowledge for weight loss, goal setting, and cognitive and behavioral strategies. Tailored feedback aimed to motivate and provide solutions via weekly 10-minute real-time video sessions. The intervention lasted 6 weeks, followed by a 6-week observation period to assess the education's lasting effects, with evaluations at baseline, 6 weeks, and 12 weeks. A generalized linear mixed model was used to evaluate time and group interactions. RESULTS: In the intention-to-treat analysis including all 60 participants, there were significant differences in weight change at 6 weeks in the MINE and MINE Plus groups, with mean weight changes of -0.74 (SD 1.96) kg (P=.03) and -1.87 (SD 1.8) kg (P<.001), respectively, while no significant change was observed in the CO group, who had a mean weight increase of 0.03 (SD 1.68) kg (P=.91). After 12 weeks, changes in body weight were -1.65 (SD 2.64) kg in the MINE group, -1.59 (SD 2.79) kg in the MINE Plus group, and 0.43 (SD 1.42) kg in the CO group. There was a significant difference between the MINE and MINE Plus groups (P<.001). Significant group × time effects were found for body weight in the MINE and CO groups (P<.001) and in the MINE Plus and CO groups (P<.001), comparing baseline and 12 weeks. Regarding physical activity and psychological factors, only body shape satisfaction and health self-efficacy were associated with improvements in the MINE and MINE Plus groups (P<.001). CONCLUSIONS: This study found that the group receiving education and tailored feedback showed significant weight loss and improvements in several psychological factors, though there were differences in the sustainability of the effects. TRIAL REGISTRATION: Korea Disease Control and Prevention Agency (KDCA) KCT0007780: https://cris.nih.go.kr/cris/search/detailSearch.do/22861.

Impact of step width on trunk motion and gait adaptation in elderly women with knee osteoarthritis.

BACKGROUND: Step width during walking can provide important information about aging and pathology. Although knee osteoarthritis (OA) is a common disease in elderly women, little is known about how different step widths influence gait parameters in patients with knee OA. OBJECTIVE: To address this, we investigated the differences between narrower and wider step width on the center of mass (CoM) and gait biomechanics of elderly women with knee OA. METHODS: Gait and CoM data were measured using a three-dimensional motion capture system and anthropometric data were acquired via standing full-limb radiography. Thirty elderly women with knee OA were divided into two groups depending on the average step width value (0.16 m). Specifically, the narrower step width group included those with a below average step width (n= 15) and the wider step width group included those with an above average step width (n= 15). The differences between the two groups were analyzed using an independentt-test. RESULTS: Walking speed, step length, knee and ankle sagittal excursion, and medial-lateral CoM range were significantly greater in the narrower group. In contrast, the medial-lateral CoM velocity, medial-lateral ground reaction force (GRF), and foot progression angle were significantly higher in wider group. The external knee adduction moment, vertical GRF, and vertical CoM did not differ between the groups. CONCLUSIONS: Our data indicate that step width in women with knee OA is associated with trunk motion and gait patterns. People with a narrower step might improve their gait function by increasing trunk frontal control to maintain gait stability. In contrast, in those with a wider step, greater toe out angle and shorter step length might be a compensatory adaptation to reduce knee loading.

Physical activity among adolescent-parent dyads: 2017-2019 Korea National Health and Nutrition Examination Surveys of Korean adolescents and that of their parents.

This study investigated physical activity (PA) levels among adolescents and their parents in South Korea. Repeated cross-sectional data from 2017-2019 Korea National Health and Nutrition Examination Survey (KNHANES) were used. The KNHANES uses a complex, multi-stage probability sample design. Data included 875 Korean adolescents aged 12 to 18years and their parents. Adolescents were asked how many days during the week they were physically active for at least 60 minutes. Compliance was defined as 4+ days per week. Logistic regressions were used and odds ratios and 95% confidence intervals were provided. The adherence to PA compliance and guideline among adolescents (≥60 min/d for at least 4 d/week) and their parents (≥600MET/min per week) were 11.54% and 23.09%, respectively. Parents who adhered to the PA guideline were more likely to have a child who also adhere to the PA than the parents who did not adhere to the PA guideline (OR=2.48, 95% CI=1.39-4.49). Only mothers (OR=1.31, 95% CI=0.65-2.57) and fathers (OR=1.37, 95% CI=0.74-2.55) were not significant in association to their adolescents' PA when complying with the PA guidelines, respectively. Parental PA appears to be important for PA among adolescents. Therefore, strategies to promote PA among adolescents should target families in South Korea.

Corrigendum to "Physical activity in the era of climate change and COVID-19 pandemic: Results from the South Korea's 2022 Report Card on physical activity for children and adolescents" [J Exercise Sci Fitness 21(1) (2023) 26-33].

[This corrects the article DOI: 10.1016/j.jesf.2022.10.014.].

Physical activity in the era of climate change and COVID-19 pandemic: Results from the South Korea's 2022 Report Card on physical activity for children and adolescents.

Background: With intensifying air pollutant levels and the COVID-19 pandemic, physical inactivity of South Korean children and adolescents may be threatened. Therefore, monitoring and surveillance of physical activity (PA) and relevant indicators are important for policy making pertaining to health promotion. Report Card is a third comprehensive evaluation of PA-related behaviors among and the sources of influence for South Korean children and adolescents. Purpose: To provide the outcome of the South Korea's 2022 Report Card on PA for children and adolescents. Methods: Based on a variety of sources including national surveys collected pre- and during-COVID-19 and information collected from government webpages, 11 indicators were graded by a committee of experts informed by the best available evidence. Data from during-COVID-19 were available for Overall PA, Sedentary Behavior, and Sleep and considered together in generating the overall grades. Results: Grades were assigned to behavioral indicators (Overall PA: D-; Active Transportation: B+; Sedentary Behavior: D; Sleep: F) and sources of Influence (Family and Peers: C-; School: A; Community and Environment: B-; Government: A). Organized Sport and PA, Active Play, and Physical Fitness could not be graded due to the lack of data. The results largely indicated that children and adolescents show unfavorable behavioral grades even with favorable grades observed for the sources of influence indicators. Trivial differences were observed pre- and during-pandemic for Overall PA (≥60 min of MVPA for ≥4 d/wk: 20.8% vs 19.9%) and Sleep (met age-specific recommendation: 14.1% vs 15.0%); however, a marked increase in Sedentary Behavior was observed (≤2 h/d screen time: 28.8% vs 20.1%). A stark weekday vs weekend difference was observed in sleep duration. In terms of PA related sources of influence, high accessibility to PA facilities (81.1%) and high satisfaction of neighborhood public transit (74.6%) and safety (80.7%) were well reflected in our Active Transportation grade (B+). Nonetheless, perception of green environments including outdoor air quality (44.0%), noise (39.6%) and green space (56.5%) showed lower scores, suggesting that new barriers to active lifestyles are emerging for South Korean children and adolescents. Gender differences were also observed for overall PA (≥60 min of MVPA for ≥4 d/wk: 29.1% for boys vs 11.3% for girls) and sleep (met age-specific recommendations: 17.3% for boys vs 11.4% for girls), but not for sedentary behavior (≤2 h/d screen time: 26.4% for boys and 24.9% for girls). Conclusions: Government and school policies/programs and the built environment are, in general, conducive to physically active lifestyles for South Korean children and adolescents; however, behavioural indicators received poor grades except for Active Transportation. A thorough evaluation of policies/programs at government, local, and school levels is needed to ensure that the efforts to have PA-enhancing infrastructure and systems are actually being translated into the behavior of children and adolescents in South Korea. Furthermore, improving PA surveillance, monitoring, and advocacy to ultimately establish healthy lifestyle patterns among children and adolescents is a top priority.

The relationship between changes in the korean fertility rate and policies to encourage fertility.

BACKGROUND: Korean government has established various policies to counter the low fertility rate since the mid-2000s, but it still has the lowest fertility rate among OECD member countries. This study investigated the relationship between changes in the Korean fertility rate and policies to encourage fertility. METHODS: This study utilized data of the total fertility rate of 250 local governments between 2014 and 2018, and a casebook of local government birth promotion policies. The dependent variable was fertility rate, and the independent variable was fertility promotion policy. Using SPSS 25.0 and M-plus 8.0 programs, descriptive statistical analysis and latent growth modeling were conducted. An unconditional quadratic function change model was selected as a final model of this study. RESULTS: The average of the initial fertility rate and the linear rate of change in the Korean fertility rate, and the rate of change of the quadratic function were all statistically significant, meaning that the fertility rate of decline increases over time. Also, the linear rate of change and the quadratic function change rate were significant, showing significant differences in the initial level and rate of change of the fertility rate between local governments. Among fertility policies, only the in-kind policy had a significant effect on the initial value of the fertility rate, meaning that the higher the number of in-kind policies, the higher the fertility rate. CONCLUSION: This study is crucial as it examined the changes in the fertility rate of Korean local governments as well as the policy factors affecting the fertility rate at a quantitative level.

Changes in the Suicide Rate of Older Adults According to Gender, Age, and Region in South Korea from 2010 to 2017.

BACKGROUND: South Korea's suicide rates are the highest among Organization for Economic Co-operation and Development (OECD) countries, making it one of the most important societal issues in South Korea. METHODS: the statistics on causes of death and resident registration central population (RRCP) provided by the National Statistical Office were used to calculate the suicide rate among older adults in Korea. We examined gender (male, female), age (young-old, old-old), and region (urban, rural) by conducting latent growth modeling to estimate changes in the overall older adult suicide rate and verify its relationship. RESULTS: over a period of 8 years, the older adult suicide rate was 104.232 on average in 2010 and it decreased by approximately 10.317 every year, and the rate of decrease gradually slowed down. The initial value of the older adult suicide rate was found to be higher among males, the old-old group, and those living in rural regions. In the quadratic function change rate, only males and the old-old group were statistically significant. CONCLUSION: in this study, the direction of and the rate of change in the older adult suicide rates and the relationship between gender, age, and region were examined. It is expected that this study will provide basic data to assist in establishing older adult suicide prevention policies, considering the gender, age, and region of the aging population.

Northeastern Asian and Jomon-related genetic structure in the Three Kingdoms period of Gimhae, Korea.

The genetic history of prehistoric and protohistoric Korean populations is not well understood because only a small number of ancient genomes are available. Here, we report the first paleogenomic data from the Korean Three Kingdoms period, a crucial point in the cultural and historic formation of Korea. These data comprise eight shotgun-sequenced genomes from ancient Korea (0.7×-6.1× coverage). They were derived from two archeological sites in Gimhae: the Yuha-ri shell mound and the Daesung-dong tumuli, the latter being the most important funerary complex of the Gaya confederacy. All individuals are from between the 4th and 5th century CE and are best modeled as an admixture between a northern China Bronze Age genetic source and a source of Jomon-related ancestry that shares similarities with the present-day genomes from Japan. The observed substructure and proportion of Jomon-related ancestry suggest the presence of two genetic groups within the population and diversity among the Gaya population. We could not correlate the genomic differences between these two groups with either social status or sex. All the ancient individuals' genomic profiles, including phenotypically relevant SNPs associated with hair and eye color, facial morphology, and myopia, imply strong genetic and phenotypic continuity with modern Koreans for the last 1,700 years.

Physical Activity Trends in Korean Adults from Korea National Health and Nutritional Examination Survey from 2014 to 2019.

The current study aimed to examine the adherence trend for aerobic and muscle-strengthening physical activity (PA) guidelines among Korean adults using the Korea National Health and Nutritional Examination Survey from 2014 to 2019. Korean adults (N = 2642) were included in the current study to examine the trend of PA adherence from 2014 to 2019. The PA guidelines are: (a) aerobic activity (a minimum of 150 min moderate to vigorous PA weekly) and (b) muscle-strengthening activity (a minimum of two days weekly). Self-report questionnaires in the survey measured both activities. The adherence to PA guidelines by survey year was examined using a multivariable logistic regression analysis adjusted for covariates. There was a significant decreasing trend in which the adherence rate to aerobic PA guidelines changed from 57.0% in 2014 to 45.6% in 2019 (p < 0.001). On the other hand, the trend in adherence rate to muscle-strengthening activity was not significant (p = 0.976). The adherence rate to muscle-strengthening activity guideline was slightly increased but still low from 20.8% to 23.3% during 2014−2019. The aerobic PA guidelines are significantly decreasing, and more than half of the Korean adults in 2019 have not followed the guidelines. In addition, there has been a slight increase in muscle-strengthening activity; however, the adherence rate is meager. Therefore, this study suggests that Korean adults' aerobic and muscle-strengthening PA participation is necessary for their low adherence rate and decline tendency.

The Effects of Children's Smartphone Addiction on Sleep Duration: The Moderating Effects of Gender and Age.

BACKGROUND: Smartphones are an important part of children's and adolescents' lives, and they often spend a lot of time using them. This study aims to precisely discover the effects of smartphone addiction on sleep duration as moderated by age and gender. MATERIALS AND METHODS: The data utilized in this study are from the 'Korean Children and Youth Panel Survey 2018' by the National Youth Policy Institute; a total of 4940 youths (2399 in grade 4 and 2541 in grade 7) from the survey were analyzed by Stata 15.0 S. The dependent variable is sleep duration, and the independent variables are the sub-factors of smartphone addiction: disturbance of adaptive functions, virtual life orientation, withdrawal, and tolerance. An independent t-test was conducted to confirm the differences in the main variables according to gender and age. Multiple regression analysis was conducted to verify the moderating effects of gender and age in the relationship between children's smartphone addiction and sleep duration. RESULTS: First, the average sleep duration among grade 4 students was 9.17 h and grade 7 students was 7.96 h. Second, sleep duration was significantly higher for males than females, while there was no difference in smartphone addiction by gender. Third, smartphone addiction, particularly the sub-factor of tolerance significantly affected sleep duration. Fourth, age significantly affected sleep duration and gender had a moderating effect on sleep duration. CONCLUSIONS: Interventions to develop a healthy smartphone usage culture on family and societal levels would be beneficial for increasing awareness of smartphone addiction and its adverse effects on children and adolescents. Furthermore, targeted intervention would be more effective at modifying addictive behavior and sleep duration than trying to administer blanket interventions to youths as a whole.

Double-gate thin film transistor with suspended-gate applicable to tactile force sensor.

This paper presents a straightforward, low-cost, and effective integration process for the fabrication of membrane gate thin film transistors (TFTs) with an air gap. The membrane gate TFT with an air gap can be used as the highly sensitive tactile force sensor. The suspended membrane gate with an air gap as the insulator layer is formed by multiple photolithography steps and photoresist sacrificial layers. The viscosity of the photoresist and the spin speed was used to modify the thickness of the air gap during the coating process. The tactile force was measured by monitoring the drain current of the TFT as the force changed the thickness of the air gap. The sensitivity of the devices was enhanced by an optimal gate size and low Young's modulus of the gate material. This simple process has the potential for the production of small, versatile, and highly sensitive sensors.

Endoscopic Transverse Gastrocsoleus Recession in Children With Cerebral Palsy.

Aim: The aim of this study was to evaluate the surgical outcome, in terms of gait improvement, of endoscopic transverse Vulpius gastrocsoleus recession in children with cerebral palsy compared to the traditional open surgery. Methods: Twenty-seven children with cerebral palsy who had undergone endoscopic transverse Vulpius gastrocsoleus recession were reviewed. For the comparison of gait improvement, independent ambulatory spastic diplegic patients who had undergone only endoscopic transverse Vulpius gastrocsoleus recession on both legs were selected. Seven (14 legs) children were included and the median age was 7 years (6-9 years). Seven age-matched patients with the same inclusion/exclusion criteria who underwent open surgery were selected as the control group. Physical examination and gait parameters were evaluated and compared between groups, including the gait deviation index (GDI), and gait profile score (GPS). Results: There was no significant complication in twenty-seven children after endoscopic transverse Vulpius gastrocsoleus recession. However, one patient required a revision open surgery at postoperative 1 year 9 months due to the recurrence of equinus and the incomplete division of the midline raphe which was noted during surgery. When comparing gait improvements, there were no differences between the endoscopic and open surgery groups in ankle dorsiflexion angle, ankle kinetics, GDI, and GPS. The postoperative peak ankle dorsiflexion during stance phase was slightly higher in the open group. Conclusion: This is the first study that evaluates gait improvement exclusively for children with spastic diplegia after endoscopic transverse Vulpius gastrocsoleus recession. The gait improvements after endoscopic surgery were comparable to the open surgery, however, the possibility of reduced improvement in ankle kinematics should be considered.

Bojungikgi-Tang, a Traditional Herbal Formula, Exerts Neuroprotective Effects and Ameliorates Memory Impairments in Alzheimer's Disease-Like Experimental Models.

Bojungikgi-tang (BJIGT; Bu Zhong Yi Qi Tang in China, Hochuekkito in Japan) is a traditional Oriental herbal formula comprised of eight medicinal herbs that has long been used for the treatment of digestive disorders. A recent clinical study from South Korea reported that BJIGT-gamibang administration may be effective in treating dementia. We aimed to establish scientific evidence for the anti-dementia effects of BJIGT using in vitro and in vivo experimental models. We measured amyloid- ß (Aß) aggregation, ß-secretase (BACE), and antioxidant activity in a cell free system. Neuroprotective effects were assessed using CCK-8. Imprinting control region (ICR) mice were divided into the following six groups: Normal control, Aß-injected, Aß-injection + oral BJIGT gavage (200, 400, or 800 mg/kg/day), and Aß-injection + oral morin administration (10 mg/kg/day). Subsequently, behavioral evaluations were conducted and brain samples were collected from all the animals and assessed. BJIGT enhanced inhibition of Aß aggregation and BACE activity in vivo, as well as antioxidant activity in in vitro, cell-free systems. BJIGT also exerted neuroprotective effects in a hydroperoxide (H2O2)-induced damaged HT22 hippocampal cell line model. In addition, BJIGT administration significantly ameliorated cognitive impairments in Aß-injected mice, as assessed by the passive avoidance and Y-maze tests. Furthermore, BJIGT treatment suppressed Aß aggregation and expression, as well as expression of Aß, NeuN, and brain-derived neurotrophic factor (BDNF) in the hippocampi of Aß-injected mice. Overall, our results demonstrate that, with further testing in clinical populations, BJIGT may have great utility for the treatment of dementia and especially Alzheimer's disease.

Effect of spinal kypho-orthosis to gait and forward flexion in Parkinson disease.

[Purpose] The gait characteristics, such as short step, decreased arm swing and stooped posture, in Parkinson disease (PD) are well established. Pharmacological and non-pharmacological treatments have been attempted to improve the gait in patients with PD. Among the non-pharmacological approaches to improve gait, spinal orthosis can be applied for patients with spinal deformity. The purpose of our study was to investigate the effect of spinal kypho-orthosis to gait in PD by using a three-dimensional analysis. [Participants and Methods] Twenty-six patients with PD with gait disturbance with forward bend posture >15°. All participants were instructed to walk along a 6-m track and turn 180° and come back to the starting point under three-dimensional motion capture. The participants performed the test again with spinal kypho-orthosis. Gait parameters during examination is compared with and without spinal kypho-orthosis. The degree of forward flexion after kypho-orthosis in patients with PD was compared. [Results] Wearing the spinal kypho-orthosis significantly improved turning performance but did not affect locomotion. The severity of forward bend posture is mildly improved after the application of spinal kypho-orthosis. [Conclusion] Spinal kypho-orthosis has a short-term effect for gait performance, particularly during turning and erect posture. Spinal kypho-orthosis can be potentially used for management of turning deficits in PD.

Strategy on navigating obstacle in patients with lumbar spinal stenosis: Relationship among trunk and pelvic movement, swing toe clearance, and muscle coordination of the stance limb.

BACKGROUND AND OBJECTIVE: Lumbar spinal stenosis (LSS) is a common spinal disorder that causes patients to assume a forward-trunk posture. Spinal alignment affects gait, muscle activity, and trunk-pelvis-limb coordination because the lumbar spine and muscles interact to allow load transfer between the lower back and pelvis during sagittal trunk movement. Therefore, we investigated the relationships among trunk and pelvic movement, swing toe clearance, and muscle coordination (isolated contraction ratios) of the stance limb during obstacle-crossing by patients with LSS. METHODS: Ten patients with LSS and ten control subjects were enrolled. All navigated an obstacle during walking. Kinematic data from the trunk and lower extremities were monitored using a three-dimensional motion analysis system. In addition, we measured the isolated contraction ratios of the gluteus medius (GMed) and vastus lateralis (VL) using surface electromyography. RESULTS: The normalized lead limb distance was significantly lower in the LSS group than in controls. The spine flexion angle when the swinging limb toe was above the obstacle was higher, but the pelvic anterior tilting angle was lower, in the LSS group. LSS patients also had a significantly lower isolated contraction ratio of the GMed in the trailing stance limb but a significantly higher VL. CONCLUSIONS: Patients with LSS adapted a poor posture and their thoracic and spinal regions were hyperflexed with restricted pelvic obliquity. This created an inefficient gait, a shorter leading limb step, and less stable muscle coordination in the stance limb. Our findings may help healthcare professionals manage patients with LSS.

Tcf7l2 plays crucial roles in forebrain development through regulation of thalamic and habenular neuron identity and connectivity.

The thalamus acts as a central integrator for processing and relaying sensory and motor information to and from the cerebral cortex, and the habenula plays pivotal roles in emotive decision making by modulating dopaminergic and serotonergic circuits. These neural compartments are derived from a common developmental progenitor domain, called prosomere 2, in the caudal forebrain. Thalamic and habenular neurons exhibit distinct molecular profile, neurochemical identity, and axonal circuitry. However, the mechanisms of how their progenitors in prosomere 2 give rise to these two populations of neurons and contribute to the forebrain circuitry remains unclear. In this study, we discovered a previously unrecognized role for Tcf7l2, a transcription factor known as the canonical Wnt nuclear effector and diabetes risk-conferring gene, in establishing neuronal identity and circuits of the caudal forebrain. Using genetic and chemical axon tracers, we showed that efferent axons of the thalamus, known as the thalamocortical axons (TCAs), failed to elongate normally and strayed from their normal course to inappropriate locations in the absence of Tcf7l2. Further experiments with thalamic explants revealed that the pathfinding defects of Tcf7l2-deficient TCAs were associated at least in part with downregulation of guidance receptors Robo1 and Robo2 expression. Moreover, the fasciculus retroflexus, the main habenular output tract, was missing in embryos lacking Tcf7l2. These axonal defects may result from dysregulation of Nrp2 guidance receptor. Strikingly, loss of Tcf7l2 caused a post-mitotic identity switch between thalamic and habenular neurons. Despite normal acquisition of progenitor identity in prosomere 2, Tcf7l2-deficient thalamic neurons adopted a molecular profile of a neighboring forebrain derivative, the habenula. Conversely, habenular neurons failed to maintain their normal post-mitotic neuronal identity and acquired a subset of thalamic neuronal features in the absence of Tcf7l2. Our findings suggest a unique role for Tcf7l2 in generating distinct neuronal phenotypes from homogeneous progenitor population, and provide a better understanding of the mechanism underlying neuronal specification, differentiation, and connectivity of the developing caudal forebrain.

Identification of a conserved cis-regulatory element controlling mid-diencephalic expression of mouse Six3.

The sine oculis homeobox protein Six3 plays pivotal roles in the development of the brain and craniofacial structures. In humans, SIX3 haploinsufficiency results in holoprosencephaly, a defect in anterior midline formation. Although much is known about the evolutionarily conserved functions of Six3, the regulatory mechanism responsible for the expression pattern of Six3 remains relatively unexplored. To understand how the transcription of Six3 is controlled during embryogenesis, we screened ∼300 kb of genomic DNA encompassing the Six3 locus for cis-acting regulatory elements capable of directing reporter gene expression to sites of Six3 transcription in transgenic mouse embryos. We identified a novel enhancer element, whose activity recapitulates endogenous Six3 expression in the ventral midbrain, pretectum, and thalamus. Cross-species comparisons revealed that this Six3 brain enhancer is functionally conserved in other vertebrates. We also showed that normal Six3 transcription in the ventral midbrain and pretectum is dependent on Ascl1, a basic helix-loop-helix proneural factor. Moreover, loss of Ascl1 resulted in downregulation of the Six3 brain enhancer activity, emphasizing its unique role in regulating Six3 expression in the developing brain.