Gene expression profiles in whole blood and associations with metabolic dysregulation in obesity

Prader-Willi syndrome gene expression profiling of obese and non-obese patients reveals transcriptional changes in CLEC4D and ANXA3

OBJECTIVES

We aimed to characterize genetic alterations in Prader-Willi syndrome (PWS) using whole genome microarrays.

METHODS

We performed mRNA expression microarray analysis using RNA isolated from whole blood of 25 PWS patients and 25 age-matched controls. After preprocessing the data to reduce heterogeneity, differentially expressed genes (DEGs) between groups were identified using a linear regression model package. Reactome pathway analysis was performed for upregulated and downregulated genes using EnrichR. Correlations between gene expression levels and clinical factors were estimated using Spearman's rank correlation coefficient.

RESULTS

Of 21,488 probes examined in the microarray analysis, 4,156 were detected. Fifty-two genes had different expression levels in children with PWS compared with healthy controls (36 genes upregulated and 16 downregulated). Twelve genes were upregulated and 13 were downregulated in obese PWS patients compared with normal-weight PWS (NW-PWS) patients. The C-type lectin domain family 4 member D (CLEC4D) was upregulated in both PWS (vs. control) and obese-PWS (vs. NW-PWS) patients, and CLEC4D expression was also correlated with body mass index-standard deviation score in PWS patients. Among the genes upregulated in obese PWS vs. NW-PWS, Annexin A3 (ANXA3), potassium inwardly rectifying channel subfamily J member 15 (KCNJ15), and selenium binding protein 1 (SELENBP1) were upregulated in obese-control vs. NW-control. Gene ontology analysis revealed that upregulated DEGs were significantly enriched in biological processes, including pathways involved in myeloid dendritic cell activation associated with CLEC4D.

CONCLUSIONS

This study revealed differences in gene expression between obese and NW-PWS patients. The regulation of macrophage infiltration by CLEC4D suggests a possible mechanism associated with obesity-related complications in PWS.

Circulating TMAO, the gut microbiome and cardiometabolic disease risk: an exploration in key precursor disorders

BACKGROUND

Elevations in the gut metabolite trimethylamine-N-oxide (TMAO) have been linked to cardiovascular and metabolic diseases. Whether elevated TMAO levels reflect early mechanistic involvement or a sequela of evolving disease awaits elucidation. The purpose of this study was to further explore these potential associations.

METHODS

We investigated relationships between circulating levels of TMAO and its pre-cursor substrates, dietary factors, gut microbiome profiles and disease risk in individuals with a Healthy BMI (18.5 < BMI < 25, n = 41) or key precursor states for cardiometabolic disease: Overweight (25 < BMI < 30 kg/m2, n = 33), Obese (BMI > 30, n = 27) and Metabolic Syndrome (MetS; ≥ 3 ATPIII report criteria, n = 39).

RESULTS

Unexpectedly, plasma [TMAO] did not vary substantially between groups (means of 3-4 µM; p > 0.05), although carnitine was elevated in participants with MetS. Gut microbial diversity and Firmicutes were also significantly reduced in the MetS group (p < 0.05). Exploratory analysis across diverse parameters reveals significant correlations between circulating [TMAO] and seafood intake (p = 0.007), gut microbial diversity (p = 0.017-0.048), and plasma [trimethylamine] (TMA; p = 0.001). No associations were evident with anthropometric parameters or cardiometabolic disease risk. Most variance in [TMAO] within and between groups remained unexplained.

CONCLUSIONS

Data indicate that circulating [TMAO] may be significantly linked to seafood intake, levels of TMA substrate and gut microbial diversity across healthy and early disease phenotypes. However, mean concentrations remain < 5 µM, with little evidence of links between TMAO and cardiometabolic disease risk. These observations suggest circulating TMAO may not participate mechanistically in cardiometabolic disease development, with later elevations likely a detrimental sequela of extant disease.

Population-enriched innate immune variants may identify candidate gene targets at the intersection of cancer and cardio-metabolic disease

Both cancer and cardio-metabolic disease disparities exist among specific populations in the US. For example, African Americans experience the highest rates of breast and prostate cancer mortality and the highest incidence of obesity. Native and Hispanic Americans experience the highest rates of liver cancer mortality. At the same time, Pacific Islanders have the highest death rate attributed to type 2 diabetes (T2D), and Asian Americans experience the highest incidence of non-alcoholic fatty liver disease (NAFLD) and cancers induced by infectious agents. Notably, the pathologic progression of both cancer and cardio-metabolic diseases involves innate immunity and mechanisms of inflammation. Innate immunity in individuals is established through genetic inheritance and external stimuli to respond to environmental threats and stresses such as pathogen exposure. Further, individual genomes contain characteristic genetic markers associated with one or more geographic ancestries (ethnic groups), including protective innate immune genetic programming optimized for survival in their corresponding ancestral environment(s). This perspective explores evidence related to our working hypothesis that genetic variations in innate immune genes, particularly those that are commonly found but unevenly distributed between populations, are associated with disparities between populations in both cancer and cardio-metabolic diseases. Identifying conventional and unconventional innate immune genes that fit this profile may provide critical insights into the underlying mechanisms that connect these two families of complex diseases and offer novel targets for precision-based treatment of cancer and/or cardio-metabolic disease.

Alteration in the mRNA expression profile of the autophagy-related mTOR pathway in schizophrenia patients treated with olanzapine

BACKGROUND

The mammalian target of rapamycin protein (mTOR) signaling pathway is involved in the pathogenesis of schizophrenia and the mechanism of extrapyramidal adverse reactions to antipsychotic drugs, which might be mediated by an mTOR-dependent autophagy impairment. This study aimed to examine the expression of mTOR pathway genes in patients with schizophrenia treated with olanzapine, which is considered an mTOR inhibitor and autophagy inducer.

METHODS

Thirty-two patients with acute schizophrenia who had been treated with olanzapine for four weeks (average dose 14.24 ± 4.35 mg/d) and 32 healthy volunteers were recruited. Before and after olanzapine treatment, the Positive and Negative Syndrome Scale (PANSS) was used to evaluate the symptoms of patients with schizophrenia, and the mRNA expression levels of mTOR pathway-related genes, including MTOR, RICTOR, RAPTOR, and DEPTOR, were detected in fasting venous blood samples from all subjects using real-time quantitative PCR.

RESULTS

The MTOR and RICTOR mRNA expression levels in patients with acute schizophrenia were significantly decreased compared with those of healthy controls and further significantly decreased after four weeks of olanzapine treatment. The DEPTOR mRNA expression levels in patients with acute schizophrenia were not significantly different from those of healthy controls but were significantly increased after treatment. The expression levels of the RAPTOR mRNA were not significantly different among the three groups. The pairwise correlations of MTOR, DEPTOR, RAPTOR, and RICTOR mRNA expression levels in patients with acute schizophrenia and healthy controls were significant. After olanzapine treatment, the correlations between the expression levels of the DEPTOR and MTOR mRNAs and between the DEPTOR and RICTOR mRNAs disappeared.

CONCLUSIONS

Abnormalities in the mTOR pathway, especially DEPTOR and mTORC2, might play important roles in the autophagy mechanism underlying the pathophysiology of schizophrenia and effects of olanzapine treatment.

Study of DYRK1B gene expression and its association with metabolic syndrome in a small cohort of Egyptians

BACKGROUND

A cluster of many risk factors for type 2 diabetes and cardiovascular disease is used to describe the metabolic syndrome (MetS). Moreover, genetic differences associated with metabolic syndrome play a key role in its prevalence and side effects. This study aims to investigate the expression of DYRK1B and its association with metabolic syndrome in a small cohort of Egyptian.

MATERIALS AND METHODS

A total of 100 adult Egyptians (50 with MetS and 50 healthy control subjects) were included to this study. Clinical, biochemical and anthropometric analysis were assessed. Relative gene expressions of DYRK1B were compared between two groups of subjects using real time PCR.

RESULTS

We observed marked overexpression in DYRK1B (p < 0.05) in MetS subjects when compared with the healthy control subjects.

CONCLUSION

This is the first study to provide evidence that DYRK1B is highly expressed among the MetS subjects.