CTCF Governs the Identity and Migration of MGE-Derived Cortical Interneurons.

The CCCTC-binding factor (CTCF) is a central regulator of chromatin topology recently linked to neurodevelopmental disorders such as intellectual disability, autism, and schizophrenia. The aim of this study was to identify novel roles of CTCF in the developing mouse brain. We provide evidence that CTCF is required for the expression of the LIM homeodomain factor LHX6 involved in fate determination of cortical interneurons (CINs) that originate in the medial ganglionic eminence (MGE). Conditiona

Thyroid-stimulating hormone pulses finely tune thyroid hormone release and TSH receptor transduction

Detection of circulating thyroid-stimulating hormone (TSH) is a first-line test of thyroid dysfunction, a major health problem (affecting about 5% of the population) that, if untreated, can lead to a significant deterioration of quality of life and adverse effects on multiple organ systems. Human TSH levels display both pulsatile and (non-pulsatile) basal TSH secretion patterns; however, the importance of these in regulating thyroid function and their decoding by the thyroid is unknown. Here, we developed a novel ultra-sensitive ELISA that allows precise detection of TSH secretion patterns with minute resolution in mouse models of health and disease. We characterised the patterns of ultradian TSH pulses in healthy, freely-behaving mice over the day-night cycle. Challenge of the thyroid axis with primary hypothyroidism due to iodine deficiency, a major cause of thyroid dysfunction worldwide, results in alterations of TSH pulsatility. Induction in mouse models of sequential TSH pulses that mimic ultradian TSH profiles in periods of minutes were more efficient than sustained rises in basal TSH levels at increasing both thyroid follicle cAMP levels, as monitored with a genetically-encoded cAMP sensor, and circulating thyroid hormone (TH). Hence this mouse TSH assay provides a powerful tool to decipher how ultradian TSH pulses encode thyroid outcomes, and to uncover hidden parameters in the TSH-TH set-point in health and disease.</p

The short mRNA isoform of the immunoglobulin superfamily, member 1 gene encodes an intracellular glycoprotein

Mutations in the immunoglobulin superfamily, member 1 gene (IGSF1/Igsf1) cause an X-linked form of central hypothyroidism. The canonical form of IGSF1 is a transmembrane glycoprotein with 12 immunoglobulin (Ig) loops. The protein is co-translationally cleaved into two sub-domains. The carboxyl-terminal domain (CTD), which contains the last 7 Ig loops, is trafficked to the plasma membrane. Most pathogenic mutations in IGSF1 map to the portion of the gene encoding the CTD. IGSF1/Igsf1 encodes a variety of transcripts. A little studied, but abundant splice variant encodes a truncated form of the protein, predicted to contain the first 2 Ig loops of the full-length IGSF1. The protein (hereafter referred to as IGSF1 isoform 2 or IGSF1-2) is likely retained in most individuals with IGSF1 mutations. [...

The anti‐FcεRI antibody MAR‐1 depletes basophils and cross‐reacts with myeloid cells through its Fc portion

International audienceIn humans, the high-affinity IgE receptor FcεRI is expressed as a tetramer in mast cells (MCs) and basophils, and as a trimer in additional myeloid cell populations, including monocytes, macrophages, dendritic cells (DCs), and Langerhans cells.1 In mice, the expression profile of FcεRI is more debatable. Some studies report FcεRI+ macrophages and DCs.2 However, recent data indicate that the anti-FcεRI mAb (clone MAR-1) used in all these studies can recognize myeloid cells in an FcεRI-independent manner, and cross-reacts with FcγRI and FcγRIV.3, 4 Since MAR-1 has been extensively used in vivo to assess the role of FcεRI and to deplete basophils,5 the off-target effects of this mAb raise concerns regarding some of the conclusions made in prior studies. We thus decided to assess by which mechanism MAR-1 cross-reacts with FcγRs, and whether this cross-reactivity accounts for some of the functions previously attributed to FcεRI and/or basophils

Murine FSH Production Depends on the Activin Type II Receptors ACVR2A and ACVR2B.

Activins are selective regulators of FSH production by pituitary gonadotrope cells. In a gonadotrope-like cell line, LβT2, activins stimulate FSH via the activin type IIA receptor (ACVR2A) and/or bone morphogenetic protein type II receptor (BMPR2). Consistent with these observations, FSH is greatly reduced, though still present, in global Acvr2a knockout mice. In contrast, FSH production is unaltered in gonadotrope-specific Bmpr2 knockout mice. In light of these results, we questioned whether an additional type II receptor might mediate the actions of activins or related TGF-β ligands in gonadotropes. We focused on the activin type IIB receptor (ACVR2B), even though it does not mediate activin actions in LβT2 cells. Using a Cre-lox strategy, we ablated Acvr2a and/or Acvr2b in murine gonadotropes. The resulting conditional knockout (cKO) animals were compared with littermate controls. Acvr2a cKO (cKO-A) females were subfertile (~70% reduced litter size), cKO-A males were hypogonadal, and both sexes showed marked decreases in serum FSH levels compared with controls. Acvr2b cKO (cKO-B) females were subfertile (~20% reduced litter size), cKO-B males had a moderate decrease in testicular weight, but only males showed a significant decrease in serum FSH levels relative to controls. Simultaneous deletion of both Acvr2a and Acvr2b in gonadotropes led to profound hypogonadism and FSH deficiency in both sexes; females were acyclic and sterile. Collectively, these data demonstrate that ACVR2A and ACVR2B are the critical type II receptors through which activins or related TGF-β ligands induce FSH production in mice in vivo

Primers used for cloning and mutagenesis.

<p>Primers used for cloning and mutagenesis.</p

Murine and rat IGSF1-2 are glycoproteins.

<p>A) CHO cells were transfected with empty vector (pcDNA4), wild-type murine IGSF1-2-Myc/His, or murine IGSF1-2 (N43Q)-Myc/His expression vectors. Whole cell protein lysates were collected and treated with PNGaseF (P), EndoH (E), or buffer alone (-) before being subjected to SDS-PAGE and immunoblotting (IB) with a Myc antibody. Molecular weight markers (in kDa) are shown at the left. Lanes are numbered at the bottom. B) CHO cells were transfected and lysates analyzed as in panel A, with the following exception: wild-type rat IGSF1-2-Myc/His was used in place of the mutant murine expression vector. *, non-specific band.</p

Murine and rat IGSF1-2 proteins are not secreted from transfected cells.

<p>HEK293 cells were transfected with expression plasmids for wild-type (WT) or glycosylation mutant (NQ) forms of murine or rat IGSF1-2, murine transthyretin (TTR), or empty vector (pcDNA4). Note, in all cases, proteins were expressed with Myc/His tags at their C-termini. Media (top two panels) and whole cell protein lysates (bottom panel) were collected and analyzed by SDS-PAGE and immunoblotting for Myc. In the middle panel, proteins in culture medium were analyzed directly. In the top panel, proteins in the media were analyzed following Ni-NTA purification and enrichment.</p