Purine Metabolite Signatures and Type 2 Diabetes: Innocent Bystanders or Actionable Items?

Transcriptome-wide association study for postpartum depression implicates altered B-cell activation and insulin resistance

Postpartum depression (PPD) affects 1 in 7 women and has negative mental health consequences for both mother and child. However, the precise biological mechanisms behind the disorder are unknown. Therefore, we performed the largest transcriptome-wide association study (TWAS) for PPD (482 cases, 859 controls) to date using RNA-sequencing in whole blood and deconvoluted cell types. No transcriptional changes were observed in whole blood. B-cells showed a majority of transcriptome-wide significant results (891 transcripts representing 789 genes) with pathway analyses implicating altered B-cell activation and insulin resistance. Integration of other data types revealed cell type-specific DNA methylation loci and disease-associated eQTLs (deQTLs), but not hormones/neuropeptides (estradiol, progesterone, oxytocin, BDNF), serve as regulators for part of the transcriptional differences between cases and controls. Further, deQTLs were enriched for several brain region-specific eQTLs, but no overlap with MDD risk loci was observed. Altogether, our results constitute a convergence of evidence for pathways most affected in PPD with data across different biological mechanisms.

Common Genetic Aberrations Associated with Metabolic Interferences in Human Type-2 Diabetes and Acute Myeloid Leukemia: A Bioinformatics Approach

Type-2 diabetes mellitus (T2D) is a chronic metabolic disorder, associated with an increased risk of developing solid tumors and hematological malignancies, including acute myeloid leukemia (AML). However, the genetic background underlying this predisposition remains elusive. We herein aimed at the exploration of the genetic variants, related transcriptomic changes and disturbances in metabolic pathways shared by T2D and AML, utilizing bioinformatics tools and repositories, as well as publicly available clinical datasets. Our approach revealed that rs11709077 and rs1801282, on PPARG, rs11108094 on USP44, rs6685701 on RPS6KA1 and rs7929543 on AC118942.1 comprise common SNPs susceptible to the two diseases and, together with 64 other co-inherited proxy SNPs, may affect the expression patterns of metabolic genes, such as USP44, METAP2, PPARG, TIMP4 and RPS6KA1, in adipose tissue, skeletal muscle, liver, pancreas and whole blood. Most importantly, a set of 86 AML/T2D common susceptibility genes was found to be significantly associated with metabolic cellular processes, including purine, pyrimidine, and choline metabolism, as well as insulin, AMPK, mTOR and PI₃K signaling. Moreover, it was revealed that the whole blood of AML patients exhibits deregulated expression of certain T2D-related genes. Our findings support the existence of common metabolic perturbations in AML and T2D that may account for the increased risk for AML in T2D patients. Future studies may focus on the elucidation of these pathogenetic mechanisms in AML/T2D patients, as well as on the assessment of certain susceptibility variants and genes as potential biomarkers for AML development in the setting of T2D. Detection of shared therapeutic molecular targets may enforce the need for repurposing metabolic drugs in the therapeutic management of AML.

The Molecular Aspect of Nephrolithiasis Development

Urolithiasis is the third most common urological disease after urinary tract infections and prostate diseases, and it is characterised by an occurrence rate of about 15%, which continues to rise. The increase in the incidence of kidney stones observed in recent decades, is most likely caused by modifications in dietary habits (high content of protein, sodium and sugar diet) and lifestyle (reduced physical activity) in all industrialised countries. Moreover, men are more likely than women to be diagnosed with kidney stones. A growing body of evidence suggests that inflammation, oxidant-antioxidant imbalance, angiogenesis, purine metabolism and urea cycle disorders may play a crucial role in nephrolithiasis development. Patients with urolithiasis were characterised by an increased level of reactive oxygen species (ROS), the products of lipid peroxidation, proinflammatory cytokines as well as proangiogenic factors, compared to controls. Furthermore, it has been shown that deficiency and disorders of enzymes involved in purine metabolism and the urea cycle might be causes of deposit formation. ROS generation suggests that the course of kidney stones might be additionally potentiated by inflammation, purine metabolism and the urea cycle. On the other hand, ROS overproduction may induce activation of angiogenesis, and thus, allows deposit aggregation.

Purine metabolites and complex diseases: role of genes and nutrients

PURPOSE OF REVIEW

Purines have several important physiological functions as part of nucleic acids and as intracellular and extracellular signaling molecules. Purine metabolites, particularly uric acid, have been implicated in congenital and complex diseases. However, their role in complex diseases is not clear and they have both beneficial and detrimental effects on disease pathogenesis. In addition, the relationship between purines and complex diseases is affected by genetic and nutritional factors. This review presents latest findings about the relationship between purines and complex diseases and the effect of genes and nutrients on this relationship.

RECENT FINDINGS

Evidence from recent studies show strong role of purines in complex diseases. Although they are causal in only few diseases, our knowledge about their role in other diseases is still evolving. Of all the purines, uric acid is the most studied. Uric acid acts as an antioxidant as well as a prooxidant under different conditions, thus, its role in disease also varies. Other purines, adenosine and inosine have been less studied, but they have neuroprotective properties which are valuable in neurodegenerative diseases.

SUMMARY

Purines are molecules with great potential in disease pathogenesis as either metabolic markers or therapeutic targets. More studies need to be conducted to understand their relevance for complex diseases.