The gene coding TDP-43, 2 or TAR DNA-binding protein 43 (Tardbp), is highly conserved throughout evolution and is found in all higher eukaryotic species including distant species Drosophila melanogaster, Xenopus laevis, and Caenorhabditis elegans (1, 2). In humans, Tardbp is located at the chromosomal locus 1p36.22 and is comprised of six exons, five of which encode a ubiquitously expressed, predominantly nuclear, 43-kDa protein that contains two RNA recognition motifs and a glycine-rich C-terminal domain, characteristic of the heterogeneous nuclear ribonucleoprotein class of proteins (3). The RNA recognition motif domains of TDP-43 are highly homologous among species; however, the glycine-rich sequence varies significantly among all species, reflecting species-specific functions in the different organisms.TDP-43 has been implicated in the regulation of gene transcription, pre-mRNA splicing, mRNA stability, and mRNA transport (4). It was first identified to bind the TAR DNA of the human immunodeficiency virus 1 long terminal repeat region. Both in vitro and in vivo experiments showed that TDP-43 represses human immunodeficiency virus 1 proviral gene expression (5). Later, it was shown to enhance exon skipping of the cystic fibrosis transmembrane conductance regulator exon 9 through binding to a (UG) m (U) n motif near the 3Ј splice site of the cystic fibrosis transmembrane conductance regulator intron 8 (6). TDP-43 was also shown to be involved in splicing of the apolipoprotein A-II (7) and survival of motor neuron (8) genes. In addition, TDP-43 has been implicated in regulation of mRNA biogenesis (9) and shown to be localized to sites of mRNA transcription and processing in neurons (10). As the glycine-rich domain of TDP-43 has been shown to mediate interactions with other heterogeneous nuclear ribonucleoprotein proteins, the low homology of this particular domain may afford a multitude of interactions that allows for diverse biological functions (11).TDP-43 has been identified as the primary protein of neuronal and glial inclusions of sporadic and familial frontotemporal lobar degeneration with ubiquitin positive inclusions (FTLD-U), as well as in sporadic and the majority of familial amyotrophic lateral sclerosis (ALS) cases (12, 13). TDP-43, normally observed in the nucleus, is found in pathological inclusions mostly in the cytoplasm and in some cases accumulates in dense deposits in the nucleus. The inclusions consist prominently of TDP-43 C-terminal fragments of ϳ20 -25 kDa. Both full-length and C-terminal fragments of TDP-43 undergo abnormal phosphorylation and ubiquitination in diseased states (13). More recently, TDP-43 inclusions are found in patients with Alzheimer and Parkinson diseases implying a common mechanism of TDP-43-related

Humans and mice with loss-of-function mutations of the genes encoding kisspeptins (Kiss1) or kisspeptin receptors (Kiss1r) are infertile due to hypogonadotropic hypogonadism. Within the hypothalamus, Kiss1 mRNA is expressed in the anteroventral periventricular nucleus (AVPV) and the arcuate nucleus (Arc). In order to better study the different populations of kisspeptin cells we generated Kiss1-Cre transgenic mice. We obtained one line with Cre activity specifically within Kiss1 neurons (line J2-4), as assessed by generating mice with Cre-dependent expression of green fluorescent protein or β-galactosidase. Also, we demonstrated Kiss1 expression in the cerebral cortex and confirmed previous data showing Kiss1 mRNA in the medial nucleus of amygdala and anterodorsal preoptic nucleus. Kiss1 neurons were more concentrated towards the caudal levels of the Arc and higher leptin-responsivity was observed in the most caudal population of Arc Kiss1 neurons. No evidence for direct action of leptin in AVPV Kiss1 neurons was observed. Melanocortin fibers innervated subsets of Kiss1 neurons of the preoptic area and Arc, and both populations expressed MC4R. Specifically in the preoptic area, 18-28% of Kiss1 neurons expressed MC4R. In the Arc, 90% of Kiss1 neurons were glutamatergic, 50% of which also were GABAergic. In the AVPV, 20% of Kiss1 neurons were glutamatergic whereas 75% were GABAergic. The differences observed between the Kiss1 neurons in the preoptic area and the Arc likely represent neuronal evidence for their differential roles in metabolism and reproduction.

Summary Zn2+ that is co-released with glutamate from mossy fiber terminals can influence synaptic function. Here, we demonstrate that synaptically released Zn2+ activates a selective post-synaptic Zn2+-sensing receptor (ZnR) in the CA3 region of the hippocampus. ZnR activation induced intracellular release of Ca2+, as well as phosphorylation of extracellular-regulated kinase and Ca2+/calmodulin kinase. ZnR-mediated Ca2+ rises were dramatically attenuated in slices from mice lacking vesicular Zn2+. In addition, knockdown of the expression of the orphan G-protein coupled receptor GPR39 attenuated ZnR activity in a neuronal cell line. Importantly, we observed widespread GPR39 labeling in CA3 neurons, suggesting a role for this receptor in mediating ZnR signaling in the hippocampus. Our results describe a unique role for synaptic Zn2+ acting as the physiological ligand of a metabotropic receptor and provide a novel pathway by which synaptic-Zn2+ can regulate neuronal function.

Preventing reproduction during nutritional deprivation is an adaptive process that is conserved and essential for the survival of species. In mammals, the mechanisms that inhibit pregnancy during starvation are complex and incompletely understood1–7. Here we show that exposure of female mice to FGF21, a fasting-induced hepatokine, mimics infertility secondary to starvation. Mechanistically, FGF21 acts on the suprachiasmatic nucleus (SCN) in the hypothalamus to suppress the vasopressin-kisspeptin signaling cascade, thereby inhibiting the proestrus surge in luteinizing hormone. Mice lacking the FGF21 co-receptor, β-Klotho, in the SCN are refractory to the inhibitory effect of FGF21 on female fertility. Thus, FGF21 defines an important liver-neuroendocrine axis that modulates female reproduction in response to nutritional challenge.

Glial cell Ca2+ signals play a key role in glial-neuronal and glial-glial network communication. Numerous studies have thus far utilized cell-permeant and injected Ca2+ indicator dyes to investigate glial Ca2+ signals in vitro and in situ. Genetically encoded fluorescent Ca2+ indicators have emerged as novel probes for investigating cellular Ca2+ signals. We have expressed one such indicator protein, the YC 3.60 cameleon, under the control of the S100β promoter and directed its expression predominantly in astrocytes and Schwann cells. Expression of YC 3.60 extended into the entire cellular cytoplasmic compartment and the fine terminal processes of protoplasmic astrocytes and Schwann cell Cajal bands. In the brain, all the cells known to express S100β in the adult or during development, expressed YC 3.60. While expression was most extensive in astrocytes, other glial cell types that express S100β, such as NG2 and CNP-positive oligodendrocyte progenitor cells (OP cells), microglia, and some of the large motor neurons in the brain stem, also contained YC 3.60 fluorescence. Using a variety of known in situ and in vivo assays, we found that stimuli known to elicit Ca2+ signals in astrocytes caused substantial and rapid Ca2+ signals in the YC 3.60-expressing astrocytes. In addition, forepaw stimulation while imaging astrocytes through a cranial window in the somatosensory cortex in live mice, revealed robust evoked and spontaneous Ca2+ signals. These results, for the first time, show that genetically encoded reporter is capable of recording activity-dependent Ca2+ signals in the astrocyte processes, and networks.

The differential expression and secretion of the neuropeptide kisspeptin from neurons in the arcuate (Arc) and anteroventral periventricular (AVPV) nuclei of the hypothalamus coordinate the temporal release of pituitary gonadotropins that control the female reproductive cycle. However, the molecular basis for this differential regulation is incompletely understood. Here, we report that liver receptor homolog-1 (LRH-1), a member of the nuclear receptor superfamily, is expressed in kisspeptin neurons in the Arc but not in the AVPV in female mice. LRH-1 binds directly to the kisspeptin (Kiss1) promoter and stimulates Kiss1 transcription. Deletion of LRH-1 from kisspeptin neurons in mice decreased Kiss1 expression in the Arc, leading to reduced plasma FSH levels, dysregulated follicle maturation, and prolongation of the estrous cycle. Conversely, overexpression of LRH-1 in kisspeptin neurons increased Arc Kiss1 expression and plasma FSH concentrations. These studies provide a molecular basis for the differential regulation of basal kisspeptin expression in Arc and AVPV neurons and reveal a prominent role for LRH-1 in hypothalamus in regulating the female reproductive axis.

In the right-hand column (line 18), the sentence should read as follows: An example of the latter situation occurred with the ␣ 1-antitrypsin paralog (Serpina1b) knockout , which only partly removes elastase inhibitory activity in the circulation, suggesting that Serpina1a also contributes to elastase control in the mouse (44). Ref. 14 in the supplemental data should read as follows: Benarafa,

PurposeCeftazidime–avibactam is a novel antimicrobial combining a third-generation cephalosporin with a non-β-lactam β-lactamase inhibitor that was recently approved to treat Gram-negative hospital- and ventilator-acquired pneumonia. The use of ceftazidime–avibactam to treat Pseudomonas aeruginosa respiratory infections in patients with cystic fibrosis (CF) has not been evaluated. In this study, we assessed the ceftazidime–avibactam susceptibility of multidrug-resistant (MDR) P. aeruginosa sputum isolates from adults with CF.MethodsSputum was collected from individuals with CF, aged ≥18 years, known to be colonized with MDR P. aeruginosa, and tested for susceptibility to 11 different antipseudomonal antimicrobial agents. Isolates were included in the analysis if they were resistant to both ceftazidime and at least one agent in ≥3 different antimicrobial categories routinely used to treat P. aeruginosa. Subject demographics and clinical characteristics were collected. Ceftazidime–avibactam-resistant isolates were screened for the presence of β-lactam-resistant mechanisms.ResultsThirty-two P. aeruginosa isolates were analyzed, of which 23 isolates were sensitive to ceftazidime–avibactam (71.9%). Ten of the isolates were mucoid and 22 isolates were nonmucoid, both demonstrating >70% susceptibility to ceftazidime–avibactam. The most notable difference in the subjects with resistant strains was an older age and lower body mass index (BMI). Ceftazidime–avibactam-resistant strains showed elevated AmpC expression in >60% of the strains and loss of OprD detection in >70% of the strains.ConclusionCeftazidime–avibactam demonstrated a significant in vitro activity against highly resistant P. aeruginosa sputum isolates from individuals with CF. Further evaluation of the cause of resistance and clinical impact of ceftazidime–avibactam in CF patients with MDR P. aeruginosa is warranted.