SIK3 suppresses neuronal hyperexcitability by regulating the glial capacity to buffer K+ and water

Glial regulation of extracellular potassium (

Neuronal activity disrupts myelinated axon integrity in the absence of NKCC1b

Through a genetic screen in zebrafish, we identified a mutant with disruption to myelin in both the CNS and PNS caused by a mutation in a previously uncharacterized gene, slc12a2b, predicted to encode a Na+, K+, and Cl− (NKCC) cotransporter, NKCC1b. slc12a2b/NKCC1b mutants exhibited a severe and progressive pathology in the PNS, characterized by dysmyelination and swelling of the periaxonal space at the axon–myelin interface. Cell-type–specific loss of slc12a2b/NKCC1b in either neurons or myelinating Schwann cells recapitulated these pathologies. Given that NKCC1 is critical for ion homeostasis, we asked whether the disruption to myelinated axons in slc12a2b/NKCC1b mutants is affected by neuronal activity. Strikingly, we found that blocking neuronal activity completely prevented and could even rescue the pathology in slc12a2b/NKCC1b mutants. Together, our data indicate that NKCC1b is required to maintain neuronal activity–related solute homeostasis at the axon–myelin interface, and the integrity of myelinated axons

An RGS-Containing Sorting Nexin Controls Drosophila Lifespan

The pursuit of eternal youth has existed for centuries and recent data indicate that fat-storing tissues control lifespan. In a D. melanogaster fat body insertional mutagenic enhancer trap screen designed to isolate genes that control longevity, we identified a regulator of G protein signaling (RGS) domain containing sorting nexin, termed snazarus (sorting nexin lazarus, snz). Flies with insertions into the 5′ UTR of snz live up to twice as long as controls. Transgenic expression of UAS-Snz from the snz Gal4 enhancer trap insertion, active in fat metabolic tissues, rescued lifespan extension. Further, the lifespan extension of snz mutants was independent of endosymbiont, e.g., Wolbachia, effects. Notably, old snz mutant flies remain active and fertile indicating that snz mutants have prolonged youthfulness, a goal of aging research. Since mammals have snz-related genes, it is possible that the functions of the snz family may be conserved to humans

DAF-16/FoxO directly regulates an atypical AMP-activated protein kinase gamma isoform to mediate the effects of insulin/IGF-1 signaling on aging in Caenorhabditis elegans

The DAF-16/FoxO transcription factor controls growth, metabolism and aging in Caenorhabditis elegans. The large number of genes that it regulates has been an obstacle to understanding its function. However, recent analysis of transcript and chromatin profiling implies that DAF-16 regulates relatively few genes directly, and that many of these encode other regulatory proteins. We have investigated the regulation by DAF-16 of genes encoding the AMP-activated protein kinase (AMPK), which has ?, ? and ? subunits. C. elegans has 5 genes encoding putative AMP-binding regulatory ? subunits, aakg-1-5. aakg-4 and aakg-5 are closely related, atypical isoforms, with orthologs throughout the Chromadorea class of nematodes. We report that ?75% of total ? subunit mRNA encodes these 2 divergent isoforms, which lack consensus AMP-binding residues, suggesting AMP-independent kinase activity. DAF-16 directly activates expression of aakg-4, reduction of which suppresses longevity in daf-2 insulin/IGF-1 receptor mutants. This implies that an increase in the activity of AMPK containing the AAKG-4 ? subunit caused by direct activation by DAF-16 slows aging in daf-2 mutants. Knock down of aakg-4 expression caused a transient decrease in activation of expression in multiple DAF-16 target genes. This, taken together with previous evidence that AMPK promotes DAF-16 activity, implies the action of these two metabolic regulators in a positive feedback loop that accelerates the induction of DAF-16 target gene expression. The AMPK ? subunit, aakb-1, also proved to be up-regulated by DAF-16, but had no effect on lifespan. These findings reveal key features of the architecture of the gene-regulatory network centered on DAF-16, and raise the possibility that activation of AMP-independent AMPK in nutritionally replete daf-2 mutant adults slows aging in C. elegans. Evidence of activation of AMPK subunits in mammals suggests that such FoxO-AMPK interactions may be evolutionarily conserved

Growth and Cyclin-E Expression in the Stony Coral Species Orbicella faveolata Post-Microfragmentation

Coral growth is critical to reef health, resilience under rapidly changing environmental conditions, and restoration efforts. Although fragmenting coral has been occurring for many years in an effort to restore reefs, recently it was discovered that microfragmenting, the process of cutting one piece of coral into many small pieces (about three to five polyps), induces exponential growth. Our study investigates the process by which microfragments of nine different genotypes from the stony coral species Orbicella faveolata grow and exhibit Cyclin-E expression. Microfragments were examined by using a high-powered dissecting microscope with a camera to document the precise areas of tissue exhibiting exponential growth. We found that new polyp formation occurs only on the microfragment edges and that edge polyp growth rates varied between different genotypes. We then extracted tissue from both the edge and the center of five genotypes for genetic analysis. We chose to analyze Cyclin-E expression because it is involved with stimulating mitotic division and is a conserved signaling pathway that is known to exist in Drosophila, mammals, and Cnidaria. Two primers for Cyclin-E were utilized to examine the level of expression for center and edge tissue. We found that Cyclin-E is expressed differentially between O. faveolata polyps, with a tendency for increased expression of the Cyclin-E in edge versus center tissue in each of five genotypes, although this result was not significant. Despite consistently higher levels of Cyclin-E expression within an organism's edge tissue, genotypes varied significantly in the degree of increased expression. This variation positively correlated with growth rate, suggesting the potential for molecular selection in aid of more rapid reef restoration. Future work will focus on deciphering the specific growth pathways involved in microfragmented coral growth and analyzing expression patterns in injured tissues

Hormonal contraceptive use and Staphylococcus aureus nasal and throat carriage in a Norwegian youth population

Background: Use of hormonal contraceptives has been associated with Staphylococcus aureus nasal carriage in adult women. However, the role of hormonal contraceptives in S. aureus colonization among adolescents and associations with progestin only contraceptives are unknown. Methods: We obtained nasal and throat swab samples from 439 girls aged 17–21 years in the population-based Tromsø study Fit Futures, 2012–2013, Norway, with information on lifestyle, health and biomarkers. We used multivariable logistic regression to study the association between use of hormonal contraceptives and Staphylococcus aureus carriage while adjusting for potential confounding factors. Results: Staphylococcus aureus nasal carriage prevalence were 34%, 42%, and 61% among progestin-only users, non-users, and progestin-estrogen combination contraceptive users, respectively (P Discussion: In this study, use of combination hormonal contraceptives was associated with higher risk of Staphylococcus aureus nasal carriage in adolescent girls. Experimental design studies are needed to establish the role of exogenous sex steroids in Staphylococcus aureus colonization in women

Independent <i>snz</i> Alleles Are Long-lived.

<p>(A) Location of the <i>C32</i>, <i>G1409</i>, and <i>SZ4089</i> P-element insertions in the <i>snazarus</i> locus. (B, C) Female (B) and male (C) control, <i>C32, G1409</i>, and <i>SZ4089</i> flies were cultured and survival was plotted. (n>80) (D, E) The lifespan of control, <i>C32</i> as well as <i>C32/SZ4089</i> (D) and <i>C32/G1409</i> (E) female transheterozygotes was assessed and plotted. (n>80) p<0.0001 by log-rank test between control and all <i>snz</i> mutant alleles. Arrowhead indicates fertility at observed timepoint. Representative data from multiple experiments is shown.</p

<i>C32</i> Enhancer Trap P-element Inserted into the 5′UTR of <i>snazarus.</i>

<p>(A) Location of the <i>C32</i> P-element insertion into the first exon of the <i>snazarus (CG1514)</i> gene. (B) Domain structure and alignment of <i>D. melanogaster</i> Snz and the three mammalian homologs. Grey rectangles represent hydrophobic patches (potential transmembrane domains). (C) SNX13, SNX14 and SNX25 mRNA expression levels were quantified with real-time PCR in uninduced 3T3-L1 preadipocytes and in induced 3T3-L1 adipocytes (n = 1). (D) Fat pads were removed from control and genetically obese <i>ob</i>/<i>ob</i> mice and the levels of SNX13, SNX14 and SNX25 expression were assessed with real-time PCR (n = 1).</p

<i>C32</i> Flies Are Long-lived.

<p>(A, B) Adult female (A) or male (B) <i>C32</i> and control <i>w¹¹¹⁸</i> flies were identically reared and survival was assessed daily. (n>80 per group, p<0.0001 by log-rank test) (C, D) Log mortality plots for adult female (C) or male (D) <i>C32</i> and control <i>w¹¹¹⁸</i> flies identically reared. (n>80 per group, p<0.0001 by log-rank test) (E) Table summarizing four independent lifespan analyses of <i>C32</i> and control flies. ^aValues are mean of the median and maximum lifespan of C32 and w¹¹¹⁸ control female (F) and male (M) flies±standard error of the mean. N, number of replicates. n, total number of flies examined. * p <0.001, ** p <0.0003 by student's t-test.</p