Metabolic alterations derived from absence of Two-Pore Channel 1 at cardiac level

Two-pore channels: going with the flows

In recent years, our understanding of the structure, mechanisms and functions of the endo-lysosomal TPC (two-pore channel) family have grown apace. Gated by the second messengers, NAADP and PI(3,5)P₂, TPCs are an integral part of fundamental signal-transduction pathways, but their array and plasticity of cation conductances (Na⁺, Ca²⁺, H⁺) allow them to variously signal electrically, osmotically or chemically. Their relative tissue- and organelle-selective distribution, together with agonist-selective ion permeabilities provides a rich palette from which extracellular stimuli can choose. TPCs are emerging as mediators of immunity, cancer, metabolism, viral infectivity and neurodegeneration as this short review attests.

Identification of a TMEM182 rs141764639 polymorphism associated with central obesity by regulating tumor necrosis factor-α in a Korean population

AIMS

To investigate the effect of a single nucleotide polymorphism (SNP) in transmembrane protein 182 (TMEM182) on the risk of having central obesity and the related phenotype.

METHODS

In total, 2141 subjects with central obesity (n = 827) and normal controls (n = 1314) were included. The most strongly associated SNPs were related to waist circumference, and one SNP, rs141764639, was identified in TMEM182 (p = 7.30E-06, q = 0.0326).

RESULTS

The TC genotype was associated with more central obesity; higher levels of blood pressure, glucose-related parameters, and inflammatory markers; abnormal lipid profiles; and smaller LDL particle sizes than the major allele homozygotes in the total population. TNF-α in the TC genotype showed extremely high levels compared to the TT genotype. There were significant interactions between the genotypes and waist circumference in relation to LDL particle size, TNF-α level, and IL-6 level. Compared with the reference group, the odds ratio for central obesity in C allele carriers was significantly increased by 2-fold.

CONCLUSIONS

The polymorphism of TMEM182 rs141764639 might have an effect on the incidence of central obesity in the Korean population by interacting with the upregulation of TNF-α, a proinflammatory cytokine. Moreover, LDL particle size, which is an atherogenic lipid profile trait, was associated with the TMEM182 rs141764639 genotype.

Integrated Multiomics Approach to Identify Genetic Underpinnings of Heart Failure and Its Echocardiographic Precursors

Background:

Heart failure (HF) may arise from alterations in metabolic, structural, and signaling pathways, but its genetic architecture is incompletely understood. To elucidate potential genetic contributors to cardiac remodeling and HF, we integrated genome-wide single-nucleotide polymorphisms, gene expression, and DNA methylation using a transomics analytical approach.

Methods:

We used robust rank aggregation (where the position of a certain gene in a rank order list [based on statistical significance level] is tested against a randomly shuffled rank order list) to derive an integrative transomic score for each annotated gene associated with a HF trait.

Results:

We evaluated ≤8372 FHS (Framingham Heart Study) participants (54% women; mean age, 55±17 years). Of these, 62 (0.7%) and 35 (0.4%) had prevalent HF with reduced ejection fraction and HF with preserved left ventricular ejection fraction, respectively. During a mean follow-up of 8.5 years (minimum–maximum, 0.005–18.6 years), 223 (2.7%) and 234 (2.8%) individuals developed incident HF with reduced ejection fraction and HF with reduced ejection fraction, respectively. Top genes included MMP20 and MTSS1 (promotes actin assembly at intercellular junctions) for left ventricular systolic function; ITGA9 (receptor for VCAM1 [vascular cell protein 1]) and C5 for left ventricular remodeling; NUP210 (expressed during myogenic differentiation) and ANK1 (cytoskeletal protein) for diastolic function; TSPAN16 and RAB11FIP3 (involved in regulation of actin cytoskeleton) for prevalent HF with reduced ejection fraction; ANKRD13D and TRIM69 for incident HF with reduced ejection fraction; HPCAL1 and PTTG1IP for prevalent HF with reduced ejection fraction; and ZNF146 (close to the COX7A1 enzyme) and ZFP3 (close to SLC52A1 —the riboflavin transporter) for incident HF with reduced ejection fraction. We tested the HF-related top single-nucleotide polymorphisms in the UK biobank, where rs77059055 in TPM1 (minor allele frequency, 0.023; odds ratio, 0.83; P =0.002) remained statistically significant upon Bonferroni correction.

Conclusions:

Our integrative transomics approach offers insights into potential molecular and genetic contributors to HF and its precursors. Although several of our candidate genes have been implicated in HF in animal models, independent replication is warranted.

[Bioinformatics analysis of expression and function of EXD3 gene in gastric cancer]

OBJECTIVE

To investigate the differentially expressed genes between gastric cancer and normal gastric mucosa by bioinformatics analysis, identify the important gene participating in the occurrence and progression of gastric cancer, and predict the functions of these genes.

METHODS

The gene expression microarray data GSE100935 (including 18 gastric cancer samples and normal gastric mucosal tissues) downloaded from the GEO expression profile database were analyzed using Morpheus to obtain the differentially expressed genes in gastric cancer, and a cluster analysis heat map was constructed. The online database UALCAN was used to obtain the expression levels of these differentially expressed genes in gastric cancer and normal gastric mucosa. The prognostic value of the differentially expressed genes in gastric cancer was evaluated with Kaplan-Meier survival analysis. GO functional enrichment analysis was performed using Fun-Rich software, and the STRING database was exploited to establish a PPI network for the differentially expressed genes.

RESULTS

A total of 45119 differentially expressed genes were identified from GSE100935 microarray data. Analysis with UALCAN showed an obvious high expression of EXD3 gene in gastric cancer, and survival analysis suggested that a high expression level of EXD3 was associated with a poorer prognosis of the patients with gastric cancer. GO functional enrichment analysis found that the differentially expressed genes in gastric cancer were involved mainly in the regulation of nucleotide metabolism and the activity of transcription factors in the cancer cells.

CONCLUSIONS

EXD3 may be a potential oncogene in gastric cancer possibly in relation to DNA damage repair. The up-regulation of EXD3 plays an important role in the development and prognosis of gastric cancer, and may serve as an important indicator for prognostic evaluation of the patients.

SOCE and STIM1 signaling in the heart: Timing and location matter

Store operated Ca²⁺ entry (SOCE) is an ancient and ubiquitous Ca²⁺ signaling pathway discovered decades ago, but the function of SOCE in human physiology is only now being revealed. The relevance of this pathway to striated muscle was solidified with the description of skeletal myopathies that result from mutations in STIM1 and Orai1, the two SOCE components. Here, we consider the evidence for STIM1 and SOCE in cardiac muscle and the sinoatrial node. We highlight recent studies revealing a role for STIM1 in cardiac growth in response to developmental and pathologic cues. We also review the role of STIM1 in the regulation of SOCE and Ca²⁺ store refilling in a non-Orai dependent manner. Finally, we discuss the importance of this pathway in ventricular cardiomyocytes where SOCE contribute to developmental growth and in pacemaker cells where SOCE likely has a fundamental to generating the cardiac rhythm.