Anti‐aging drugs reduce hypothalamic inflammation in a sex‐specific manner

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137690/1/acel12590-sup-0001-FigS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137690/2/acel12590_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137690/3/acel12590.pd

Transient early food restriction leads to hypothalamic changes in the long‐lived crowded litter female mice

Transient nutrient restriction in the 3 weeks between birth and weaning (producing “crowded litter” or CL mice) leads to a significant increase in lifespan and is associated with permanent changes in energy homeostasis, leptin, and insulin sensitivity. Here, we show this brief period of early food restriction leads to permanent modulation of the arcuate nucleus of the hypothalamus (ARH), markedly increasing formation of both orexigenic agouti‐related peptide (AgRP) and anorexigenic proopiomelanocortin (POMC) projections to the paraventricular nucleus of the hypothalamus (PVH). An additional 4 weeks of caloric restriction, after weaning, does not further intensify the formation of AgRP and POMC projections. Acute leptin stimulation of 12‐month‐old mice leads to a stronger increase in the levels of hypothalamic pStat3 and cFos activity in CL mice than in controls, suggesting that preweaning food restriction leads to long‐lasting enhancement of leptin signaling. In contrast, FoxO1 nuclear exclusion in response to insulin is equivalent in young adult CL and control mice, suggesting that hypothalamic insulin signaling is not modulated by the crowded litter intervention. Markers of hypothalamic reactive gliosis associated with aging, such as Iba1‐positive microglia and GFAP‐positive astrocytes, are significantly reduced in CL mice as compared to controls at 12 and 22 months of age. Lastly, age‐associated overproduction of TNF‐α in microglial cells is reduced in CL mice than in age‐matched controls. Together, these results suggest that transient early life nutrient deprivation leads to long‐term hypothalamic changes which may contribute to the longevity of CL mice.e12379Transient nutrient restriction in the 3 weeks between birth and weaning (producing “crowded litter” or CL mice) leads to long‐term hypothalamic changes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111266/1/phy212379.pd

How can countries create outbreak response policies that are sensitive to maternal health?

From BMJ via Jisc Publications RouterEnsuring women’s need for sexual and reproductive healthcare are met should be a priority during disease outbreaks, say Maira L S Takemoto and colleaguesOpen access fees were paid by the UN University-International Institute for Global Health.373pubpu

DNA replication stress restricts ribosomal DNA copy number

Ribosomal RNAs (rRNAs) in budding yeast are encoded by ~100–200 repeats of a 9.1kb sequence arranged in tandem on chromosome XII, the ribosomal DNA (rDNA) locus. Copy number of rDNA repeat units in eukaryotic cells is maintained far in excess of the requirement for ribosome biogenesis. Despite the importance of the repeats for both ribosomal and non-ribosomal functions, it is currently not known how “normal” copy number is determined or maintained. To identify essential genes involved in the maintenance of rDNA copy number, we developed a droplet digital PCR based assay to measure rDNA copy number in yeast and used it to screen a yeast conditional temperature-sensitive mutant collection of essential genes. Our screen revealed that low rDNA copy number is associated with compromised DNA replication. Further, subculturing yeast under two separate conditions of DNA replication stress selected for a contraction of the rDNA array independent of the replication fork blocking protein, Fob1. Interestingly, cells with a contracted array grew better than their counterparts with normal copy number under conditions of DNA replication stress. Our data indicate that DNA replication stresses select for a smaller rDNA array. We speculate that this liberates scarce replication factors for use by the rest of the genome, which in turn helps cells complete DNA replication and continue to propagate. Interestingly, tumors from mini chromosome maintenance 2 (MCM2)-deficient mice also show a loss of rDNA repeats. Our data suggest that a reduction in rDNA copy number may indicate a history of DNA replication stress, and that rDNA array size could serve as a diagnostic marker for replication stress. Taken together, these data begin to suggest the selective pressures that combine to yield a “normal” rDNA copy number

Screen for essential genes that maintain rDNA copy number.

<p>(A) Distribution of rDNA copy number across the yeast ts mutant collection. 175 and 113 strains had significantly lower (<70 copies) and higher copy number (>119 copies) respectively (p<0.05). (B) -log₁₀ transformed FDR q-values for significantly enriched (p<0.001) GO terms (sorted in order of increasing p-values from top to bottom) in low copy number hits.</p

Low rDNA copy number confers advantage under DNA replication stress.

<p>(A) 3 independent isolates each with normal or low rDNA copy number were generated by subcultuing wild-type or <i>fob1Δ GAL-POL1</i> cells in medium containing high or low galactose (high or low levels of Pol1 respectively) for ~50–75 generations (<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007006#pgen.1007006.s006" target="_blank">S2 Table</a>) and 5-fold serial dilutions spotted on to medium with DNA replication stress (low Pol1). (B) 10-fold serial dilutions of wild-type and <i>fob1Δ</i> cells (~200–250 rDNA copies) along with cells having 20–110 rDNA copies [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007006#pgen.1007006.ref003" target="_blank">3</a>] were spotted on medium containing hydroxyurea (HU). rDNA copy number was confirmed by ddPCR. Error bars represent standard deviation for each individual reaction.</p

Design and validation of a ddPCR assay for rDNA copy number measurement.

<p>(A) Targets (red bars) within the rDNA and single copy reference (<i>TUB1</i>) loci in yeast. (B) rDNA copy number in 3 independent isolates each of 2 different wild-type laboratory yeast strains, BY4741 and W303, and 4 isogenic strains with varying rDNA copy number generated by Ide et al. [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007006#pgen.1007006.ref003" target="_blank">3</a>]. (C) rDNA copy number in 8 technical replicates each of BY4741 and W303. (D) rDNA copy number in 3 independent isolates each of mutants with expanded rDNA arrays. Error bars represent standard deviation for each individual reaction.</p

Contraction of the rDNA array promotes timely completion of DNA replication and cell cycle progression.

<p>Wild-type <i>GAL-POL1</i> cells were subcultured in medium containing high or low levels of galactose for ~75 generations to generate 3 independent isolates each with normal or low rDNA copy number (<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007006#pgen.1007006.s006" target="_blank">S2 Table</a>). (A) Representative DNA content profiles over time are shown for asynchronous cultures of isolates with normal (i) and low (ii) rDNA copy number following inoculation into the indicated medium which determines high or low levels of DNA polymerase α. (B) Fraction of cells in S-phase in each of the 4 conditions in (A). Error bars indicate standard deviation based on 3 independent isolates. Statistical significance of differences between fraction of cells in S-phase in high and low levels of DNA polymerase α was calculated using a standard 2-tailed t-test. *—p<0.05, ****—p<0.0001. (C) Increased rARS firing in nicotinamide exacerbates growth defects under conditions of DNA replication stress.</p

Cargo-free particles divert neutrophil-platelet aggregates to reduce thromboinflammation

The combination of inflammation and thrombosis is a hallmark of many cardiovascular diseases. Under such conditions, platelets are recruited to an area of inflammation by forming platelet-leukocyte aggregates via interaction of PSGL-1 on leukocytes and P-selectin on activated platelets, which can bind to the endothelium. While particulate drug carriers have been utilized to passively redirect leukocytes from areas of inflammation, the downstream impact of these carriers on platelet accumulation in thromboinflammatory conditions has yet to be studied. Here, we explore the ability of polymeric particles to divert platelets away from inflamed blood vessels both in vitro and in vivo. We find that untargeted and targeted micron-sized polymeric particles can successfully reduce platelet adhesion to an inflamed endothelial monolayer in vitro in blood flow systems and in vivo in a lipopolysaccharide-induced, systemic inflammation murine model. Our data represent initial work in developing cargo-free, anti-platelet therapeutics specifically for conditions of thromboinflammation

Long-lived crowded-litter mice exhibit lasting effects on insulin sensitivity and energy homeostasis

The action of nutrients on early postnatal growth can influence mammalian aging and longevity. Recent work has demonstrated that limiting nutrient availability in the first 3 wk of life [by increasing the number of pups in the crowded-litter (CL) model] leads to extension of mean and maximal lifespan in genetically normal mice. In this study, we aimed to characterize the impact of early-life nutrient intervention on glucose metabolism and energy homeostasis in CL mice. In our study, we used mice from litters supplemented to 12 or 15 pups and compared those to control litters limited to eight pups. At weaning and then throughout adult life, CL mice are significantly leaner and consume more oxygen relative to control mice. At 6 mo of age, CL mice had low fasting leptin concentrations, and low-dose leptin injections reduced body weight and food intake more in CL female mice than in controls. At 22 mo, CL female mice also have smaller adipocytes compared with controls. Glucose and insulin tolerance tests show an increase in insulin sensitivity in 6 mo old CL male mice, and females become more insulin sensitive later in life. Furthermore, β-cell mass was significantly reduced in the CL male mice and was associated with reduction in β-cell proliferation rate in these mice. Together, these data show that early-life nutrient intervention has a significant lifelong effect on metabolic characteristics that may contribute to the increased lifespan of CL mice