Placental expression of microRNAs in infants born small for gestational age

INTRODUCTION

The molecular mechanisms behind poor foetal growth are not fully known. The aim of this study was to explore global microRNA expression in placentas of infants born small for gestational age (SGA) compared to infants with a normal birth weight (NBW).

METHODS

Placental biopsies from term infants were identified in a biobank and divided into four groups: infants born SGA with (n = 13) or without (n = 9) exposure to low maternal gestational weight gain (GWG) and infants born with NBWs with (n = 20) or without (n = 26) exposure to low GWG. All women and infants were healthy, and no woman smoked during pregnancy. Only vaginal deliveries were included. Next-generation sequencing was performed with single read sequencing of >9 million reads per sample. Differential microRNA expression was analysed using ANOVA for unequal variances (Welch) with multiple testing corrections through the Benjamini-Hochberg method. A fold change >2 and a corrected p value < 0.05 were considered significant. Adjustments for possible confounding factors were made using a linear regression model.

RESULTS

A total of 1870 known, mature human microRNAs were detected in the sample. MiR-3679-5p and miR-193b-3p were significantly upregulated, and miR-379-3p, miR-335-3p, miR-4532, miR-519e-3p, miR-3065-5p, and miR-105-5p were significantly downregulated after adjustment for potential confounding factors in SGA infants with normal GWG compared to infants with NBWs and normal GWG.

DISCUSSION

Infants born unexplained SGA show differential microRNA expression in their placenta. Important pathways for the differentially expressed microRNAs include inflammation and the insulin-IGF system.

Evidence for a polygenic contribution to androgenetic alopecia

BACKGROUND

Male pattern baldness (androgenetic alopecia, AGA) is a highly heritable trait and the most common form of hair loss in humans. Eight genome-wide significant risk loci for AGA have been identified.

OBJECTIVES

To determine whether a polygenic component contributes to the genetic risk for AGA.

METHODS

This study used a German case-control sample for AGA, which comprised 581 severely affected patients and 617 controls, to determine the contribution of polygenic variance to AGA risk. The sample was divided evenly into discovery and test samples. An additive polygenic risk score was calculated from risk alleles with increasingly liberal P-values in the discovery dataset, which was then used to test for the enrichment of AGA risk score alleles in the independent test samples.

RESULTS

The polygenic score analysis provided significant evidence for a polygenic contribution to AGA where the amount of variance explained was 1·4-4·5%.

CONCLUSION

This study provides evidence for the specific contribution of a polygenic component to the overall heritable risk for AGA. To some degree, the polygenic architecture of AGA might reflect the complexity of the biological pathways involved. Further analyses and strategies that complement conventional genome-wide association studies are needed to identify these factors. These may include pathway-based analyses, the analysis of functional candidate genes and tests for epistatic effects with known loci.

Investigation of the male pattern baldness major genetic susceptibility loci AR/EDA2R and 20p11 in female pattern hair loss

BACKGROUND

The aetiology of female pattern hair loss (FPHL) is largely unknown. However, it is hypothesized that FPHL and male pattern baldness (AGA) share common susceptibility alleles. The two major susceptibility loci for AGA are the androgen receptor (AR)/ectodysplasin A2 receptor (EDA2R) locus on the X-chromosome, and a locus on chromosome 20p11, for which no candidate gene has yet been identified.

OBJECTIVES

To examine the role of the AR/EDA2R and 20p11 loci in the development of FPHL using 145 U.K. and 85 German patients with FPHL, 179 U.K. supercontrols and 150 German blood donors.

METHODS

Patients and controls were genotyped for 25 single nucleotide polymorphisms (SNPs) at the AR/EDA2R locus and five SNPs at the 20p11 locus.

RESULTS

Analysis of the AR/EDA2R locus revealed no significant association in the German sample. However, a nominally significant association for a single SNP (rs1397631) was found in the U.K. sample. Subgroup analysis of the U.K. patients revealed significant association for seven markers in patients with an early onset (P = 0·047 after adjustment for the testing of multiple SNPs by Monte Carlo simulation). No significant association was obtained for the five 20p11 variants, either in the overall samples or in the analysis of subgroups.

CONCLUSIONS

The observed association suggests that the AR/EDA2R locus confers susceptibility to early-onset FHPL. Our results do not implicate the 20p11 locus in the aetiology of FPHL.

Oral immunosuppressive medication for growing pigs in transplantation studies

Immunosuppressive (IS) medication is needed to avoid graft rejection in porcine transplantation models. An ideal IS therapy should have no side-effects, but increased susceptibility to infections, disturbed intestinal microflora and toxic effects on organs and tissues are commonly reported. The aim of the present study was to design an IS protocol with tacrolimus and mycophenolic acid to be used for maintenance therapy in the post-transplant period. An eligible whole blood trough value for tacrolimus was 5–15 μg/L. Conventional specific pathogen-free pigs were fitted with an indwelling catheter under general anaesthesia, and after the acclimatization period three groups were formed: group A ( n= 4) received 0.15 mg/kg body weight (BW) twice daily tacrolimus and 500 mg twice daily mycophenolic acid; group B ( n= 4) received 0.3 mg/kg BW twice daily tacrolimus and 500 mg twice daily mycophenolic acid; group C ( n= 2) did not receive any medication. Daily clinical examinations and analyses of blood concentrations of tacrolimus and glucose were performed. Total and differential white blood cell counts, enzyme activities, bilirubin and electrolyte concentrations were measured every fourth day. At the end of the experiment, the pigs were killed with an overdose of pentobarbital intravenously and a necropsy was performed immediately. All animals seemed to tolerate the IS treatment well. No alterations in their clinical state of health were observed throughout the study and daily weight gain was similar for the three groups. The necropsy did not reveal any pathological findings related to medication. The study showed that 0.25 mg/kg BW twice daily tacrolimus and 500 mg twice daily mycophenolic acid would be an appropriate maintenance dosage for conventional pigs.

Susceptibility variants on chromosome 7p21.1 suggest HDAC9 as a new candidate gene for male-pattern baldness

BACKGROUND

Male-pattern baldness (androgenetic alopecia, AGA) is the most common form of hair loss among humans. Research has shown that it is caused by genetic factors. Numerous studies have unequivocally identified two major genetic risk loci for AGA: the X-chromosomal AR/EDA2R locus, and the PAX1/FOXA2 locus on chromosome 20.

OBJECTIVES

To identify further candidate genes for AGA, and thus gain further insights into this phenotype.

METHODS

A German sample of 581 severely affected cases and 617 controls was used to perform a genome-wide association study. The identified associated locus was further analysed by fine-mapping, and then independently replicated in an Australian sample. Expression and pathway analyses were performed to characterize the susceptibility gene identified.

RESULTS

The most significant association signal was obtained for rs756853 (P = 1·64 × 10(-7) ), which is located intronically in the histone deacetylase 9 (HDAC9) gene. Fine-mapping and a family-based analysis revealed that rs756853 and the 6-kb distal rs2249817 were the most highly associated single nucleotide polymorphisms. The association finding was replicated in an independent Australian sample, when the analysis was restricted to severely affected cases and unaffected controls (P = 0·026). Analysis of rs2249817 in a combined sample of severely affected German and Australian cases and unaffected controls revealed a strong association signal (P = 9·09 × 10(-8) ). Tissue expression studies demonstrated HDAC9 expression in various tissues, including tissues of relevance to AGA. No strong genotypic effects were observed in genotype-specific expression or splice studies. Pathway analyses supported the hypothesis that HDAC9 plays a functional role in AGA via interaction with the AR gene.

CONCLUSIONS

The present study suggests that HDAC9 is the third AGA susceptibility gene.

Colloid centrifugation removes seminal plasma and cholesterol from boar spermatozoa

The objective of the present study was to investigate the effect of Single-Layer Centrifugation (SLC) on boar spermatozoa, namely the effect of removal of seminal plasma proteins and cholesterol from the surface of spermatozoa. The presence of porcine seminal plasma proteins I and II (PSP-I/PSP-II) before and after SLC was studied using immunofluorescence, whereas the removal of cholesterol was shown qualitatively by thin-layer chromatography (TLC). Finally, the integrity of the sperm plasma membrane was observed by electron microscopy. It was shown that the seminal plasma proteins PSP-I and -II were removed from spermatozoa during SLC but could be restored by adding seminal plasma to the SLC-selected sperm samples. Some cholesterol was also lost from the spermatozoa during SLC but the plasma membrane itself appeared to be morphologically intact. Further studies are underway to examine the relevance of these findings to boar sperm cryopreservation and sperm fertility.

Cytokine induction by immunostimulatory DNA in porcine PBMC is impaired by a hairpin forming sequence motif from the genome of Porcine Circovirus type 2 (PCV2)

Porcine Circovirus type 2 (PCV2) can cause postweaning multisystemic wasting syndrome (PMWS) in young pigs with severe immunosuppression as a major characteristic of the disease complex. Despite the dramatic involvement of the immune system, the interaction between PCV2 and the host is until date not well understood. The DNA genome of PCV2 contains sequences that in synthetic form (oligodeoxyribonucleotides; ODNs) can act immunomodulatory on porcine peripheral blood mononuclear cells (poPBMCs) in vitro. One such sequence (ODN PCV2/1) acts inhibitory on interferon (IFN)-α production induced by immunostimulatory DNA but not that induced by RNA, and the inhibitory activity is dependent on secondary structure formation. In the present study, the characteristic of ODN PCV2/1 was examined further by altering the nucleotide sequence to disrupt hairpin structure formation but still enable multimer structures through G-tetrads. This modification resulted in loss of IFN-α-inhibitory activity of the ODN and thus indicated the importance of hairpin structures. In addition, ODN PCV2/1 was compared to another inhibitory ODN (IRS 869) previously used in human and murine cells. In contrast to ODN PCV2/1, ODN IRS 869 did not inhibit IFN-α production induced by class A ODN 2216 but was a more efficient inhibitor of IFN-α production induced by plasmid DNA than ODN PCV2/1. In cultures induced by the RNA stimulator Poly I:C, however, a strong synergistic IFN-α stimulatory effect was seen in combination with ODN IRS 869. These results indicate that ODN PCV2/1 and ODN IRS 869 function through separate mechanisms to affect cytokine production by immune cells. The effect of ODN PCV2/1 was studied further by monitoring the expression of mRNA for IFN-α, IL-12p40, IL-10, IL-6, IFN-γ, IL-1β, TGF-β, and TNF-α in cultures of poPBMC stimulated with ODN 2216 or Poly I:C. Results from qPCR analyses showed that ODN PCV2/1 clearly inhibited the expression of IFN-α, IL-12p40, IL-10 and IL-6 when induced by ODN 2216, but did not seem to affect any of the cytokines examined when induced by Poly I:C. Initial studies using confocal microscopy and fluorochrome labelled ODNs indicate that ODN 2216 and ODN PCV2/1 co-localize in subpopulations of poPBMC.

The TRAF1/C5 locus confers risk for familial and severe alopecia areata

BACKGROUND

Alopecia areata (AA) is a common hair loss disorder with a complex mode of inheritance. Autoimmune mechanisms are presumed to be crucial aetiologically. It is plausible that a number of autoimmune disorders may share a common genetic background. This phenomenon has been demonstrated in previous studies, which have shown an overlap of susceptibility alleles between AA and other autoimmune disorders. Recent studies have shown that genetic variants on the TRAF1/C5 (tumor necrosis factor receptor-associated factor 1, complement component 5) locus confer susceptibility to rheumatoid arthritis (RA).

OBJECTIVES

To examine the role of the TRAF1/C5 locus in the development of AA using a large sample of 1,195 patients with AA and 1280 controls.

METHODS

We genotyped the two most significant single nucleotide polymorphisms (SNPs) (rs10818488, rs2416808) from a former RA candidate gene study. After having obtained evidence for association, we performed a fine-mapping study and genotyped the locus with an additional 27 SNPs.

RESULTS

While no significant result was obtained for the overall sample, rs2416808 showed significant associations in the analysis of the subgroups with severe AA and with a positive family history. The most significant P-value for rs2416808 was in familial cases (P = 0.004, P(corr) = 0.026). The fine mapping revealed significant associations for four additional SNPs in the analysis of subgroups, with rs2416808 remaining the most significant marker.

CONCLUSIONS

Our results point to the involvement of the TRAF1/C5 locus in the aetiology of familial and severe AA, and provide further support for a shared aetiology between AA and other autoimmune disorders.

Effects of streptozotocin-induced diabetes in domestic pigs with focus on the amino acid metabolism

Streptozotocin (STZ) given intravenously destroys pancreatic beta cells and is widely used in animal models to mimic type 1 diabetes. The effects of STZ on the clinical state of health and metabolism were studied in six high health certified domestic pigs weighing 19+/-1.3 kg at the start of the experiment. A single STZ dose of 150 mg/kg of body weight successfully induced hyperglycaemia and alterations in amino acid metabolism. Within 9 h after STZ administration, the blood glucose values fell from 5.4-7.5 mmol/L to 0.8-2.2 mmol/L. Hypoglycaemia was treated with 0.5 g glucose/kg body weight. In all pigs, hyperglycaemia was produced 24 h after STZ treatment, and 3 days after STZ injection, the glucose concentration was >25 mmol/L. Mean C-peptide concentration was 0.25+/-0.16 microg/L since 2 days after STZ injection until the end of the study. The serum concentration of the branched-chain amino acids (BCAA) increased four-fold, and alanine and taurine decreased by approximately 70% and 50%, respectively, after STZ treatment. All but one pig remained brisk and the physical examination was normal except for a retarded growth rate and a reduction of the skeletal muscle. At the end of the study, the pigs were moderately emaciated. Postmortem examination confirmed muscle wasting and a reduction of abdominal and subcutaneous fat. In conclusion, STZ-induced diabetes in pigs fulfils the requirements for a good animal model for type 1 diabetes with respect to clinical signs of the disease and alterations in the carbohydrate and amino acid metabolism.

[Tuberous sclerosis: diagnostic criteria and new treatment approaches]

With a prevalence of 1 in 6,000 births, tuberous sclerosis is a relatively frequent hamartoma and tumor syndrome inherited as an autosomal dominant trait, which manifests primarily on the skin and in the central nervous system. Decisive factors for morbidity and mortality and thus for the prognosis are the changes in the central nervous system in the form of cortical hamartomas. Treatment for many years consisted solely in using nonspecific symptomatic approaches; dermatological therapy comprised mainly laser or electroacoustic ablation of facial angiofibromas. New models of therapy hinder the pathogenesis of tuberous sclerosis. Various studies provided evidence that the macrolide rapamycin decreases growth of brain and kidney tumors by specific inhibition of mTOR kinase. Synergistic effects were observed in combination therapy with the cytokine IFN-gamma.

The R620W polymorphism in PTPN22 confers general susceptibility for the development of alopecia areata

BACKGROUND

The functional R620W (c.1858C>T) variant of the protein tyrosine phosphatase nonreceptor 22 gene (PTPN22) has been associated with a variety of autoimmune disorders. A recent study has suggested that R620W also contributes to the severe form of alopecia areata (AA).

OBJECTIVES

We sought to replicate the finding of an association between PTPN22 and severe AA. In addition, we wanted to study the effect of PTPN22 on the general risk to develop AA and on other subtypes of AA (mild AA, early/late age at onset, positive/negative family history).

METHODS

The R620W variant was genotyped in a large case-control sample of Belgian-German origin with 435 patients and 628 controls.

RESULTS

Significant results were obtained for the overall collective of patients with AA (P=0.007). Subdividing the sample according to severity of AA, family history and age at onset, we detected lowest P-values for patients with the severe form of AA (Pcorr=0.036), with a positive family history (Pcorr=0.042) and with an age at onset<or=20 years (Pcorr=0.048).

CONCLUSIONS

Our results suggest the R620W variant of PTPN22 as a general risk factor in AA with the strongest effect observed among patients with a severe type of AA, a positive family history or an early onset of disease.

Investigation of the functional variant c.-169T > C of the Fc receptor-like 3 (FCRL3) gene in alopecia areata

A functional variant in the Fc receptor-like 3 (FCRL3) gene has been implicated in susceptibility to autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus and autoimmune thyroid disease. Investigating a large case-control sample of patients with alopecia areata (AA), we found no evidence for the involvement of FCRL3 in susceptibility to AA.

Investigation of the p.Ser278Arg polymorphism of the autoimmune regulator (AIRE) gene in alopecia areata

A recent study has suggested that the g.961C >G (p.Ser278Arg) variant of the autoimmune regulator (AIRE) gene contributes to susceptibility to alopecia areata (AA). We attempted to replicate this finding using a case-control sample of Belgian-German origin (273 patients and 283 controls). Despite adequate power, our study results do not support a significant association of the risk allele in our AA patient sample. This remained the case when we stratified our sample according to severity and family history of disease. Our study results do not support the hypothesis that the g.961C >G (p.Ser278Arg) polymorphism of the AIRE gene is associated with an increased risk for AA.

A non-sense mutation in the corneodesmosin gene in a Mexican family with hypotrichosis simplex of the scalp

BACKGROUND

Hypotrichosis simplex of the scalp (HSS; MIM 146520) is a rare autosomal dominant form of non-syndromic alopecia that affects men and women equally. Up to now, only a small number of families with HSS have been reported. The affected individuals experience a diffuse progressing hair loss from childhood to adulthood that is confined to the scalp. Recently, HSS has been mapped to the short arm of chromosome 6 (6p21.3), allowing mutations in the corneodesmosin gene (CDSN) to be identified as the cause of the disorder. To date, two stop mutations have been found in three unrelated families with HSS of different ethnic origin.

OBJECTIVES

To describe the first HSS-family with Latin American (Mexican) background comprising 6 generations and to identify a mutation in the CDSN gene.

PATIENTS/METHODS

The patients were examined by a clinician and blood samples were taken. After DNA extraction, sequencing analysis of the CDSN gene and restriction enzyme analysis with PsuI were performed.

RESULTS

By direct sequencing of the two exons of the CDSN gene, a nonsense mutation was identified in the index patient in exon 2, resulting in a premature stop codon (Y239X). The mutation co-segregates perfectly in the family with the disease and was not found in 300 control chromosomes using a restriction enzyme analysis with PsuI.

CONCLUSIONS

A nonsense mutation was identified in the first family with HSS of Latin American ethnical background. Our data provide molecular genetic evidence for a 3rd stop mutation in exon 2 of the CDSN gene being responsible for HSS. All to date known nonsense mutations responsible 3 for HSS are clustered in a region of 40 amino acids which is in accordance with a dominant negative effect conferred by aggregates of truncated CDSN proteins.

[Purely cutaneous Rosai-Dorfman disease]

Sinus histiocytosis with massive lymphadenopathy or Rosai-Dorfman disease is a non-Langerhans cell histiocytosis of unknown etiolosy. The most characteristic feature is lymphadenopathy, especially that of cervical lymph nodes. In approximately 40% of patients there are extranodal manifestations of the disease. Skin is the most commonly affected organ (27%). We report a 79-year-old female patient with purely cutaneous manifestations. This form of the disease is a very rare differential diagnosis in dermatology.