A sensitive and specific direct competitive enzyme-linked immunosorbent assay (dc-ELISA) was studied in this paper for the detection of di-(2-ethylhexyl) phthalate (DEHP) based on an antigen-coating format. The DEHP-specific polyclonal antibody was raised in rabbits and used to construct the dc-ELISA for the measurement of DEHP. The conjugates of the antibody with horseradish peroxidase (HRP) were used as the detection probe. Under optimal conditions, the assay had a detection limit (LOD) of about 0.0042 ng mL À1 , with an apparent linear range of 10 À3 À10 3 ng mL À1 (R 2 ¼ 0.998). The cross-reactivity with six other structurally related phthalate esters was below 1%. The recoveries of DEHP ranged from 80.8% to 119.2% indicating that the method was successfully applied for the determination of DEHP in infant supplies.

Leptin, secreted by peripheral adipocytes, binds the leptin receptor (Lepr) in the hypothalamus, thereby contributing to the regulation of satiety and body weight. Lepr is expressed in the embryonic brain as early as embryonic day 12.5. However, the function of Lepr in neural precursor cells in the brain has not been resolved. To address this issue, we crossed the Lepr flox/flox mice with each of Shh-Cre mice (Shh, sonic hedgehog) and Nestin (Nes)-Cre mice. We found that deletion of Lepr specifically in nestin-expressing cells led to extreme obesity, but the conditional null of Lepr in Shh-expressing cells had no obvious phenotype. Moreover, the level of leptin-activated pSTAT3 decreased in the anterior and central subregions of the arcuate hypothalamus of Shh-Cre; Lepr flox/flox mice compared with the controls. By contrast, in Nes-Cre; Lepr flox/flox mice, the level of leptin-activated pSTAT3 decreased in all subregions including the anterior, central, and posterior arcuate hypothalamus as well as the dorsomedial, ventromedial, and median eminence of the hypothalamus, revealing that the extensive lack of Lepr in the differentiated neurons of the hypothalamus in the conditional null mice. Notably, conditional deletion of Lepr in nestin-expressing cells enhanced the differentiation of neural precursor cells into neurons and oligodendroglia but inhibited differentiation into astrocytes early in postnatal development of hypothalamus. Our results suggest that Lepr expression in neural precursor cells is essential for maintaining normal body weight as well as the differentiation of neural precursor cells to the neural/glial fate in the hypothalamus shortly after birth.

In response to central nervous system (CNS) injury, astrocytes go through a series of alterations, referred to as reactive astrogliosis, ranging from changes in gene expression and cell hypertrophy to permanent astrocyte borders around stromal cell scars in CNS lesions. The mechanisms underlying injury-induced reactive astrocytes in the adult CNS have been extensively studied. However, little is known about injuryinduced reactive astrocytes during early postnatal development. Astrocytes in the mouse cortex are mainly produced through local proliferation during the first 2 weeks after birth. Here we show that Sox2, a transcription factor critical for stem cells and brain development, is expressed in the early postnatal astrocytes and its expression level was increased in reactive astrocytes after traumatic brain injury (TBI) at postnatal day (P) 7 in the cortex. Using a tamoxifen-induced hGFAP-CreERT2; Sox2 flox/flox ; Rosa-tdT mouse model, we found that specific knockout of Sox2 in astrocytes greatly inhibited the proliferation of reactive astrocytes, the formation of glia limitans borders and subsequently promoted the tissue recovery after postnatal TBI at P7 in the cortex. In addition, we found that injury-induced glia limitans borders were still formed at P2 in the wild-type mouse cortex, and knockout of Sox2 in astrocytes inhibited the reactivity of both astrocytes and microglia. Together, these findings provide evidence that Sox2 is essential for the reactivity of astrocytes in response to the cortical TBI during the early postnatal period and suggest that Sox2-dependent astrocyte reactivity is a potential target for therapeutic treatment after TBI.

Krüppel‐like Factor 7 (KLF7) is a zinc finger transcription factor that has a critical role in cellular differentiation, tumorigenesis, and regeneration. Mutations in Klf7 are associated with autism spectrum disorder, which is characterized by neurodevelopmental delay and intellectual disability. Here we show that KLF7 regulates neurogenesis and neuronal migration during mouse cortical development. Conditional depletion of KLF7 in neural progenitor cells resulted in agenesis of the corpus callosum, defects in neurogenesis, and impaired neuronal migration in the neocortex. Transcriptomic profiling analysis indicated that KLF7 regulates a cohort of genes involved in neuronal differentiation and migration, including p21 and Rac3. These findings provide insights into our understanding of the potential mechanisms underlying neurological defects associated with Klf7 mutations.