A new perspective on the current and future development potential of ABCG1

Longitudinal association between DNA methylation and type 2 diabetes: findings from the KORA F4/FF4 study

BACKGROUND

Type 2 diabetes (T2D) has been linked to changes in DNA methylation levels, which can, in turn, alter transcriptional activity. However, most studies for epigenome-wide associations between T2D and DNA methylation comes from cross-sectional design. Few large-scale investigations have explored these associations longitudinally over multiple time-points.

METHODS

In this longitudinal study, we examined data from the Cooperative Health Research in the Region of Augsburg (KORA) F4 and FF4 studies, conducted approximately seven years apart. Leucocyte DNA methylation was assessed using the Illumina EPIC and 450K arrays. Linear mixed-effects models were employed to identify significant associations between methylation sites and diabetes status, as well as with fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), homoeostasis model assessment of beta cell function (HOMA-B), and homoeostasis model assessment of insulin resistance (HOMA-IR). Interaction effects between diabetes status and follow-up time were also examined. Additionally, we explored CpG sites associated with persistent prediabetes or T2D, as well as the progression from normal glucose tolerance (NGT) to prediabetes or T2D. Finally, we assessed the associations between the identified CpG sites and their corresponding gene expression levels.

RESULTS

A total of 3,501 observations from 2,556 participants, with methylation measured at least once across two visits, were included in the analyses. We identified 64 sites associated with T2D including 15 novel sites as well as known associations like those with the thioredoxin-interacting protein (TXNIP) and ATP-binding cassette sub-family G member 1 (ABCG1) genes. Of these, eight CpG sites exhibited different rates of annual methylation change between the NGT and T2D groups, and seven CpG sites were linked to the progression from NGT to prediabetes or T2D, including those annotated to mannosidase alpha class 2a member 2 (MAN2A2) and carnitine palmitoyl transferase 1 A (CPT1A). Longitudinal analysis revealed significant associations between methylation and FPG at 128 sites, HbA1c at 41 sites, and HOMA-IR at 57 sites. Additionally, we identified 104 CpG-transcript pairs in whole blood, comprising 40 unique CpG sites and 96 unique gene transcripts.

CONCLUSIONS

Our study identified novel differentially methylated loci linked to T2D as well as to changes in diabetes status through a longitudinal approach. We report CpG sites with different rates of annual methylation change and demonstrate that DNA methylation associated with T2D is linked to following transcriptional differences. These findings provide new insights into the molecular mechanisms of diabetes development.

Combined action of dietary-based approaches and therapeutic agents on cholesterol metabolism and main related diseases

BACKGROUND

Dyslipidaemia is among the major causes of severe diseases and, despite being well-established, the hypocholesterolaemic therapies still face significant concerns about potential side effects (such as myopathy, myalgia, liver injury digestive problems, or mental fuzziness in some people taking statins), interaction with other drugs or specific foods. Accordingly, this review describes the latest developments in the most effective therapies to control and regulate dyslipidaemia.

SCOPE AND APPROACH

Herein, the metabolic dynamics of cholesterol and their integration with the current therapies: statins, bile acid sequestrants, fibrates, niacin, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, reconstituted high-density lipoprotein (rHDL), or anti-inflammatory and immune-modulating therapies), were compared focusing their effectiveness, patients' adhesion and typical side-effects. Likewise, the interaction of these therapies with recommended dietary habits, focusing functional foods and nutraceuticals uptake were also considered.

KEY FINDINGS AND CONCLUSIONS

Since none of the current therapeutic alternatives represent an ideal solution (mainly due to side-effects or patients' tolerance), the potential adjuvant action of selected diets (and other healthy habits) was proposed as a way to improve the cholesterol-lowering effectiveness, while reducing the adverse effects caused by dose-increase or continuous uptake of alternating therapeutic agents. In general, the relevance of well-adapted diets must be acknowledged and their potential effects must be exhorted among patients, who need to be aware of the associated multifactorial advantages.

Up-regulation of ABCG1 is associated with methotrexate resistance in acute lymphoblastic leukemia cells

Acute lymphoblastic leukemia (ALL) is a prevalent hematologic malignancy in children, and methotrexate (MTX) is a widely employed curative treatment. Despite its common use, clinical resistance to MTX is frequently encountered. In this study, an MTX-resistant cell line (Reh-MTXR) was established through a stepwise selection process from the ALL cell line Reh. Comparative analysis revealed that Reh-MTXR cells exhibited resistance to MTX in contrast to the parental Reh cells. RNA-seq analysis identified an upregulation of ATP-binding cassette transporter G1 (ABCG1) in Reh-MTXR cells. Knockdown of ABCG1 in Reh-MTXR cells reversed the MTX-resistant phenotype, while overexpression of ABCG1 in Reh cells conferred resistance to MTX. Mechanistically, the heightened expression of ABCG1 accelerated MTX efflux, leading to a reduced accumulation of MTX polyglutamated metabolites. Notably, the ABCG1 inhibitor benzamil effectively sensitized Reh-MTXR cells to MTX treatment. Moreover, the observed upregulation of ABCG1 in Reh-MTXR cells was not induced by alterations in DNA methylation or histone acetylation. This study provides insight into the mechanistic basis of MTX resistance in ALL and also suggests a potential therapeutic approach for MTX-resistant ALL in the future.