Impact of gain-of-function mutations in the low-density lipoprotein receptor-related protein 5 (LRP5) on glucose and lipid homeostasis

Human Placental LRP5 and Sclerostin are Increased in Gestational Diabetes Mellitus Pregnancies

INTRODUCTION

The low-density lipoprotein receptor-related protein 5 (LRP5) and its inhibitor sclerostin, are key components of bone metabolism and potential contributors to type 2 diabetes mellitus susceptibility. This study aims at evaluating the expression of placental LRP5 and sclerostin in pregnancies with gestational diabetes mellitus (GDM) and investigate possible associations with umbilical sclerostin concentrations and clinical outcomes in mothers and their neonates.

METHODS

Twenty-six GDM-mothers and 34 non-GDM mothers of Caucasian origin and their neonates admitted in a gynecology and obstetrics department of a university hospital were included in this study. Demographic data and maternal fasting glucose concentrations (24-28 weeks of gestation) were retrieved from the patients' medical records. Placental LRP5 was determined by immunohistochemistry (IHC) and Western blotting analysis; placental sclerostin was determined by IHC. Umbilical serum sclerostin concentrations were measured by ELISA.

RESULTS

Placental sclerostin IHC intensity values were positively correlated with LRP5 values as detected either by IHC (r = 0.529; P < .001) or Western blotting (r = 0.398; P = .008), with pregestational maternal body mass index values (r = 0.299; P = .043) and with maternal fasting glucose concentrations (r = 0.475; P = .009). Placental sclerostin and LRP5 were significantly greater in GDM compared with non-GDM placentas (histo-score: 65.08 ± 17.09 vs 11.45 ± 2.33, P < .001; 145.53 ± 43.74 vs 202.88 ± 58.65, P < .001; respectively).

DISCUSSION

Sclerostin and LRP5 were detected in human placentas. The overexpression of placental sclerostin and LRP5 values in GDM compared with non-GDM pregnancies, as well as the positive association of placental sclerostin values with pregestational maternal body mass index and maternal fasting glucose concentrations may indicate the development of an adaptive mechanism in face of maternal hyperglycemia.

Identification of hsa_circ_0001445 of a novel circRNA-miRNA-mRNA regulatory network as potential biomarker for coronary heart disease

Objects

To evaluate the hsa_circ_0001445 level in peripheral blood leukocytes of patients with coronary heart disease (CHD) and its related clinical factors, and predict its circRNA-miRNA-mRNA regulatory network in CHD pathogenesis via bioinformatics analysis.

Methods

Peripheral blood leukocytes were isolated from the whole blood samples of 94 CHD patients (aged 65.96 ± 9.78 years old) and 126 healthy controls (aged 60.75 ± 8.81 years old). qRT-PCR was used to quantify the expression level of circRNA and subsequently analyze its association with CHD clinical parameters. Via bioinformatics algorithm and GEO datasets, differential miRNA expression was evaluated using the Limma package. A miRNA-mRNA regulatory network was predicted by cyTargetLinker. ClusterProfiler was employed to perform functional enrichment analysis of the circRNA network to investigate its role in CHD pathogenesis.

Results

The expression of hsa_circ_0001445 in peripheral blood leukocytes of CHD patients was downregulated compared with that of healthy controls. Positive correlations were evident between hsa_circ_0001445 expression level and the levels of hemoglobin, triglycerides, high- and low-density lipoprotein cholesterol. A significant negative correlation was also found between hsa_circ_0001445 expression level and age and the neutrophil level. Low expression of hsa_circ_0001445 exhibited a discriminatory ability between CHD patients and healthy controls with a sensitivity of 67.5% and a specificity of 76.6% (p &lt; 0.05). By bioinformatics analysis, 405 gene ontology terms were identified. The Kyoto Encyclopedia of Genes and Genomes terms focused principally on the PI3K-Akt signaling pathway. hsa_circ_0001445 was associated with the expression of three miRNAs that may regulate 18 genes involved in KEGG processes: hsa-miR-507, hsa-miR-375–3p, and hsa-miR-942–5p.

Conclusion

The hsa_circ_0001445 level in peripheral blood leukocytes may serve as a biomarker for CHD diagnosis. Our work on circRNA-miRNA-mRNA networks suggests a potential role for hsa_circ_0001445 in CHD development.

Early-Onset Osteoporosis

Osteoporosis is a skeletal disorder with enhanced bone fragility, usually affecting the elderly. It is very rare in children and young adults and the definition is not only based on a low BMD (a Z-score < - 2.0 in growing children and a Z-score ≤ - 2.0 or a T-score ≤ - 2.5 in young adults) but also on the occurrence of fragility fractures and/or the existence of underlying chronic diseases or secondary factors such as use of glucocorticoids. In the absence of a known chronic disease, fragility fractures and low BMD should prompt extensive screening for secondary causes, which can be found in up to 90% of cases. When fragility fractures occur in childhood or young adulthood without an evident secondary cause, investigations should explore the possibility of an underlying monogenetic bone disease, where bone fragility is caused by a single variant in a gene that has a major role in the skeleton. Several monogenic forms relate to type I collagen, but other forms also exist. Loss-of-function variants in LRP5 and WNT1 may lead to early-onset osteoporosis. The X-chromosomal osteoporosis caused by PLS3 gene mutations affects especially males. Another recently discovered form relates to disturbed sphingolipid metabolism due to SGMS2 mutations, underscoring the complexity of molecular pathology in monogenic early-onset osteoporosis. Management of young patients consists of treatment of secondary factors, optimizing lifestyle factors including calcium and vitamin D and physical exercise. Treatment with bone-active medication should be discussed on a personalized basis, considering the severity of osteoporosis and underlying disease versus the absence of evidence on anti-fracture efficacy and potential harmful effects in pregnancy.

Relationship between the Chromosome Structural Dynamics and Gene Expression—A Chicken and Egg Dilemma?

Prokaryotic transcription was extensively studied over the last half-century. A great deal of data has been accumulated regarding the control of gene expression by transcription factors regulating their target genes by binding at specific DNA sites. However, there is a significant gap between the mechanistic description of transcriptional control obtained from in vitro biochemical studies and the complexity of transcriptional regulation in the context of the living cell. Indeed, recent studies provide ample evidence for additional levels of complexity pertaining to the regulation of transcription in vivo, such as, for example, the role of the subcellular localization and spatial organization of different molecular components involved in the transcriptional control and, especially, the role of chromosome configurational dynamics. The question as to how the chromosome is dynamically reorganized under the changing environmental conditions and how this reorganization is related to gene expression is still far from being clear. In this article, we focus on the relationships between the chromosome structural dynamics and modulation of gene expression during bacterial adaptation. We argue that spatial organization of the bacterial chromosome is of central importance in the adaptation of gene expression to changing environmental conditions and vice versa, that gene expression affects chromosome dynamics.

Frizzled-related proteins 4 (SFRP4) rs1802073G allele predicts the elevated serum lipid levels during acitretin treatment in psoriatic patients from Hunan, China

Background

Acitretin is a second-generation synthetic retinoid, and is widely used for treating the severe psoriasis vulgaris. However, it should be chosen with caution for its cardiovascular risk, and it is reported that acitretin may increase the serum lipids. The purpose of this study is to investigate the relationship between the Frizzled-related proteins 4 (SFRP4) rs1802073 polymorphism and the changes of serum lipids in Chinese psoriatic patients during the treatment with acitretin.

Methods

In our study, 100 psoriatic patients were recruited systematically treated with acitretin (30 mg/day) for at least eight weeks. Data of the patients’ demographic and clinical characteristics and the results of serum triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were collected pre- and post-treatment.

Results

A total of 84 psoriatic patients were enrolled and divided into three groups by SFRP4 rs1802073 genotypes. The patients who carried with TT genotype had maintained levels of TG and LDL-C after acitretin treatment, while patients with GG/GT genotypes had significantly elevated levels of serum TG and LDL-C compared to the TT genotype (ΔTG%: 27.53 ± 59.13 vs −1.47 ± 37.79, p = 0.026, ΔLDL-C%: 10.62 ± 26.57 vs −1.29 ± 17.07, p = 0.042). The association of rs1802073 with TG and LDL-C profiles remained significant after adjusting for age, gender, and body mass index. Although without significance, the pre-post change in serum level of TC across rs1802073 GG/GT genotypes demonstrated a trend similar to TG and LDL, and the serum level of HDL-C demonstrated a trend opposite to TG, TC and LDL.

Conclusions

Our results demonstrated that SFRP4 rs1802073 polymorphism was found to be associated with elevated serum lipid levels after acitretin treatment, and it may serve as a genetic marker of safe and precise treatment for individual psoriatic patients.