Combinatorial Roles of Heparan Sulfate Proteoglycans and Heparan Sulfates in Caenorhabditis elegans Neural Development

Heparan sulfate proteoglycans (HSPGs) play critical roles in the development and adult physiology of all metazoan organisms. Most of the known molecular interactions of HSPGs are attributed to the structurally highly complex heparan sulfate (HS) glycans. However, whether a specific HSPG (such as syndecan) contains HS modifications that differ from another HSPG (such as glypican) has remained largely unresolved. Here, a neural model in C. elegans is used to demonstrate for the first time the relationship between specific HSPGs and HS modifications in a defined biological process in vivo. HSPGs are critical for the migration of hermaphrodite specific neurons (HSNs) as genetic elimination of multiple HSPGs leads to 80% defect of HSN migration. The effects of genetic elimination of HSPGs are additive, suggesting that multiple HSPGs, present in the migrating neuron and in the matrix, act in parallel to support neuron migration. Genetic analyses suggest that syndecan/sdn-1 and HS 6-O-sulfotransferase, hst-6, function in a linear signaling pathway and glypican/lon-2 and HS 2-O-sulfotransferase, hst-2, function together in a pathway that is parallel to sdn-1 and hst-6. These results suggest core protein specific HS modifications that are critical for HSN migration. In C. elegans, the core protein specificity of distinct HS modifications may be in part regulated at the level of tissue specific expression of genes encoding for HSPGs and HS modifying enzymes. Genetic analysis reveals that there is a delicate balance of HS modifications and eliminating one HS modifying enzyme in a compromised genetic background leads to significant changes in the overall phenotype. These findings are of importance with the view of HS as a critical regulator of cell signaling in normal development and disease

Feasibility of a controlled trial aiming to prevent excessive pregnancy-related weight gain in primary health care

<p>Abstract</p> <p>Background</p> <p>Excessive gestational weight gain and postpartum weight retention may predispose women to long-term overweight and other health problems. Intervention studies aiming at preventing excessive pregnancy-related weight gain are needed. The feasibility of implementing such a study protocol in primary health care setting was evaluated in this pilot study.</p> <p>Methods</p> <p>A non-randomized controlled trial was conducted in three intervention and three control maternity and child health clinics in primary health care in Finland. Altogether, 132 pregnant and 92 postpartum women and 23 public health nurses (PHN) participated in the study. The intervention consisted of individual counselling on physical activity and diet at five routine visits to a PHN and of an option for supervised group exercise until 37 weeks' gestation or ten months postpartum. The control clinics continued their usual care. The components of the feasibility evaluation were 1) recruitment and participation, 2) completion of data collection, 3) realization of the intervention and 4) the public health nurses' experiences.</p> <p>Results</p> <p>1) The recruitment rate was slower than expected and the recruitment period had to be prolonged from the initially planned three months to six months. The average participation rate of eligible women at study enrolment was 77% and the drop-out rate 15%. 2) In total, 99% of the data on weight, physical activity and diet and 96% of the blood samples were obtained. 3) In the intervention clinics, 98% of the counselling sessions were realized, their contents and average durations were as intended, 87% of participants regularly completed the weekly records for physical activity and diet, and the average participation percentage in the group exercise sessions was 45%. 4) The PHNs regarded the extra training as a major advantage and the high additional workload as a disadvantage of the study.</p> <p>Conclusion</p> <p>The study protocol was mostly feasible to implement, which encourages conducting large trials in comparable settings.</p> <p>Trial registration</p> <p>Current Controlled Trials ISRCTN21512277</p

Primary Prevention of Gestational Diabetes Mellitus and Large-for-Gestational-Age Newborns by Lifestyle Counseling: A Cluster-Randomized Controlled Trial

In a cluster-randomized trial, Riitta Luoto and colleagues find that counseling on diet and activity can reduce the birthweight of babies born to women at risk of developing gestational diabetes mellitus (GDM), but fail to find an effect on GDM

Agreement between pedometer and accelerometer in measuring physical activity in overweight and obese pregnant women

<p>Abstract</p> <p>Background</p> <p>Inexpensive, reliable objective methods are needed to measure physical activity (PA) in large scale trials. This study compared the number of pedometer step counts with accelerometer data in pregnant women in free-living conditions to assess agreement between these measures.</p> <p>Methods</p> <p>Pregnant women (n = 58) with body mass index ≥25 kg/m²at median 13 weeks' gestation wore a GT1M Actigraph accelerometer and a Yamax Digi-Walker CW-701 pedometer for four consecutive days. The Spearman rank correlation coefficients were determined between pedometer step counts and various accelerometer measures of PA. Total agreement between accelerometer and pedometer step counts was evaluated by determining the 95% limits of agreement estimated using a regression-based method. Agreement between the monitors in categorising participants as active or inactive was assessed by determining Kappa.</p> <p>Results</p> <p>Pedometer step counts correlated moderately (r = 0.36 to 0.54) with most accelerometer measures of PA. Overall step counts recorded by the pedometer and the accelerometer were not significantly different (medians 5961 vs. 5687 steps/day, p = 0.37). However, the 95% limits of agreement ranged from -2690 to 2656 steps/day for the mean step count value (6026 steps/day) and changed substantially over the range of values. Agreement between the monitors in categorising participants to active and inactive varied from moderate to good depending on the criteria adopted.</p> <p>Conclusions</p> <p>Despite statistically significant correlations and similar median step counts, the overall agreement between pedometer and accelerometer step counts was poor and varied with activity level. Pedometer and accelerometer steps cannot be used interchangeably in overweight and obese pregnant women.</p

Feasibility of a lifestyle intervention in early pregnancy to prevent deterioration of glucose tolerance

<p>Abstract</p> <p>Background</p> <p>In conjunction with the growing prevalence of obesity and the older age of pregnant women gestational diabetes (GDM) is a major health problem.</p> <p>The aim of the study was to evaluate if a lifestyle intervention since early pregnancy is feasible in improving the glucose tolerance of women at a high-risk for GDM in Finland.</p> <p>Methods</p> <p>A 75-g oral glucose tolerance test (OGTT) was performed in early pregnancy (n = 102). Women at high risk for GDM (n = 54) were randomized at weeks 8-12 from Apr 2005 to May 2006 to a lifestyle intervention group (n = 27) or to a close follow-up group (n = 27). An OGTT was performed again at weeks 26-28 for the lifestyle intervention and close follow-up groups.</p> <p>Results</p> <p>The values of the OGTT during the second trimester did not differ between the lifestyle intervention and close follow-up groups. In the lifestyle intervention group three women had GDM in the second trimester and respectively one woman in the close follow up group. Insulin therapy was not required in both groups. The intervention resulted in somewhat lower weight gain 11.4 ± 6.0 kg vs. 13.9 ± 5.1 kg, p = 0.062, adjusted by the prepregnancy weight.</p> <p>Conclusions</p> <p>Early intervention with an OGTT and simple lifestyle advice is feasible. A more intensive lifestyle intervention did not offer additional benefits with respect to glucose tolerance, although it tended to ameliorate the weight gain.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01130012">NCT01130012</a></p

SDN-1 and HS 2-O-sulfate regulate parallel neuron migration pathways.

<p>(A) Removing heparan 2-O-sulfation in <i>sdn-1</i> mutants significantly enhances HSN migration defects. Note the increased proportion (39%) of HSNs that fail to migrate at all in <i>sdn-1 hst-2</i> double mutants. Genetic elimination of <i>hst-6</i> or <i>hst-3.2</i> in <i>sdn-1</i> mutant background does not change the HSN migration phenotype. (B–D) Expression profiles of <i>sdn-1</i>, <i>hst-3.2</i> and <i>hst-3.1</i> reporter genes. (B) <i>sdn-1</i> reporter is expressed predominantly in the nervous system, including neurons of the nerve ring (arrow) and in the ventral (VNC; arrowheads) and dorsal nerve cords. (C) <i>hst-3.2</i> reporter is also expressed in neurons as seen in some neurons in the nerve ring in the pharynx (arrows) and in the tail ganglia and along ventral nerve cord axon tracks (arrowheads). (D) <i>hst-3.1</i> reporter is expressed in the muscle; both the pharyngeal muscle (arrow) and body wall muscle express <i>hst-3.1</i> reporter. Scale bars B, D; 50 µm, C; 20 µm.</p

HS and HSPGs are required for axon guidance but not for process outgrowth.

<p>All HSNs analysed extended axon projections irrespective of the position of the neural cell body. However, axon guidance was defective in mutants lacking HS biosynthetic enzymes or HSPGs. (A) 17% of all HSNs in <i>sdn-1</i> (<i>ok449</i>) mutants failed to migrate at all and remain in the tail as the right HSN (HSNR) shown here. The HSN extends axon projection along the ventral nerve cord (arrowheads). In this animal, the left HSN (HSNL) is in wild type position. (B) In some mutants, the HSN cell bodies have migrated to wild type position, but project axons aberrantly. In this <i>hst-3.2</i> (<i>tm3006</i>) <i>hst-2</i> (<i>ok595</i>) double mutant, a branch of the HSN axon projects posteriorly (arrowheads). (C) In some mutants, the HSN axons project posteriorly (arrowheads) and completely fail to follow their stereotyped pathway. (A to C); Dashed line indicates the position of vulva. Anterior is to the left, posterior to the right, ventral down in all panels. Scale bars 50 µm.</p

Combinatorial effects of eliminating HS epimerase and O-sulfotransferases for neural migration.

<p>(A) Removal of HS 3- and 6-O-sulfotransferases enhances the defects in HS epimerase mutants. <i>C. elegans</i> with genetic deletion in either <i>hst-3.1</i> or <i>hst-6</i> or in combination of both have wild type HSN migration. However, eliminating either <i>hst-3.1</i> or <i>hst-6</i> in <i>hse-5</i> epimerase background significantly enhances the neural phenotype. In contrast, eliminating <i>hst-2</i> in <i>hse-5</i> background does not alter the combined phenotype as compared to <i>hst-2</i> mutants alone. (B) Genetic elimination of HS 2- and 6-O-sulfotransferases has strong additive effects on HSN migration. Note the significant increase in neurons (17%) that fail to migrate at all in <i>hst-6 hst-2</i> double mutants. Genetic removal of <i>hst-3.1</i> suppresses HSN migration defects of <i>hst-2</i> and <i>hst-6 hst-2</i> double mutants.</p