Regulation of Hepatic Cholesteryl Ester Transfer Protein Expression and Reverse Cholesterol Transport by Inhibition of DNA Topoisomerase II

Targeting TOP2B as a vulnerability in aging and aging-related diseases

The ongoing trend of rapid aging of the global population has unavoidably resulted in an increase in aging-related diseases. There is an immense amount of interest in the scientific community for the identification of molecular targets that may effectively mitigate the process of aging and aging-related diseases. The enzyme Topoisomerase IIβ (TOP2B) plays a crucial role in resolving the topological challenges that occur during DNA-related processes. It is believed that the disruption of TOP2B function contributes to the aging of cells and tissues, as well as the development of age-related diseases. Consequently, targeting TOP2B appears to be a promising approach for interventions aimed at mitigating the effects of aging. This review focuses on recent advancements in the understanding of the role of TOP2B in the processing of aging and aging-related disorders, thus providing a novel avenue for the development of anti-aging strategies.

Endoplasmic Reticulum Stress and Its Impact on Adipogenesis: Molecular Mechanisms Implicated

Endoplasmic reticulum (ER) stress plays a pivotal role in adipogenesis, which encompasses the differentiation of adipocytes and lipid accumulation. Sustained ER stress has the potential to disrupt the signaling of the unfolded protein response (UPR), thereby influencing adipogenesis. This comprehensive review illuminates the molecular mechanisms that underpin the interplay between ER stress and adipogenesis. We delve into the dysregulation of UPR pathways, namely, IRE1-XBP1, PERK and ATF6 in relation to adipocyte differentiation, lipid metabolism, and tissue inflammation. Moreover, we scrutinize how ER stress impacts key adipogenic transcription factors such as proliferator-activated receptor γ (PPARγ) and CCAAT-enhancer-binding proteins (C/EBPs) along with their interaction with other signaling pathways. The cellular ramifications include alterations in lipid metabolism, dysregulation of adipokines, and aged adipose tissue inflammation. We also discuss the potential roles the molecular chaperones cyclophilin A and cyclophilin B play in adipogenesis. By shedding light on the intricate relationship between ER stress and adipogenesis, this review paves the way for devising innovative therapeutic interventions.

Inhibition of Vascular Calcification

Objective- Vascular calcification is a major risk factor for rupture of atherosclerotic plaques. High expression of BMP2 (bone morphogenetic protein 2) in lesions suggests its importance in vascular calcification during atherosclerosis. Teniposide is a Topo II (DNA topoisomerase II) inhibitor and is used for cancer treatment. Previously, we reported that teniposide activated macrophage ABCA1 (ATP-binding cassette transporter A1) expression and free cholesterol efflux indicating Topo II inhibitors may demonstrate antiatherogenic properties. Herein, we investigated the effects of teniposide on the development of atherosclerosis and vascular calcification in apoE^-/- (apoE deficient) mice. Approach and Results- apoE^-/- mice were fed high-fat diet containing teniposide for 16 weeks, or prefed high-fat diet for 12 weeks followed by high-fat diet containing teniposide for 4 weeks. Atherosclerosis and vascular calcification were determined. Human aortic smooth muscle cells were used to determine the mechanisms for teniposide-inhibited vascular calcification. Teniposide reduced atherosclerotic lesions. It also substantially reduced vascular calcification without affecting bone structure. Mechanistically, teniposide reduced vascular calcification by inactivating BMP2/(pi-Smad1/5/8 [mothers against decapentaplegic homolog 1, 5, and 8])/RUNX2 (runt-related transcription factor 2) axis in a p53-dependent manner. Furthermore, activated miR-203-3p by teniposide functioned as a link between activated p53 expression and inhibited BMP2 expression in inhibition of calcification. Conclusions- Our study demonstrates that teniposide reduces vascular calcification by regulating p53-(miR-203-3p)-BMP2 signaling pathway, which contributes to the antiatherogenic properties of Topo II inhibitors.

Development of Hepatic Steatosis After Chemotherapy for Non-Hodgkin Lymphoma

Nonalcoholic fatty liver disease is the most common liver disorder in the developed world. Although typically reflecting caloric overload, it can also be secondary to drug toxicity. We aimed to describe the incidence and risk factors for de novo steatosis during chemotherapy for non‐Hodgkin lymphoma (NHL). In this retrospective case‐control study, adult patients with NHL were treated with rituximab, cyclophosphamide, doxorubicin, prednisone, and vincristine (R‐CHOP) or R‐CHOP + etoposide (EPOCH‐R). Patients with liver disease or steatosis were excluded. Abdominal computed tomography was performed pretreatment and at 3‐ to 6‐month intervals and reviewed for steatosis. Patients with de novo steatosis were matched 1:1 to controls by age, sex, and ethnicity. Of 251 treated patients (median follow‐up 53 months), 25 (10%) developed de novo steatosis, with the vast majority (23 of 25; 92%) developing it after chemotherapy. Of those, 14 (61%) developed steatosis within the first 18 months posttreatment and 20 (87%) within 36 months. Cases had higher baseline body mass index (BMI; mean ± SD, 29.0 ± 6.5 versus 26.0 ± 5.2 kg/m²; P = 0.014) and hyperlipidemia (12% versus 2%; P = 0.035). Although their weights did not change during chemotherapy, BMI in cases increased by 2.4 ± 2 kg/m² (mean ± SD) from end of treatment to steatosis compared to 0.68 ± 1.4 in controls (P = 0.003). Etoposide‐containing regimens were associated with a shorter time to steatosis (median 34 weeks versus 154 weeks; P < 0.001) despite similar baseline risk factors. Conclusion: The recovery period from NHL chemotherapy appears to be a “hot spot” for development of fatty liver, driven by early posttreatment weight gain, especially in subjects with baseline risk factors.

Dysfunctional HDL in diabetes mellitus and its role in the pathogenesis of cardiovascular disease

Coronary artery disease, the leading cause of death in the developed and developing countries, is prevalent in diabetes mellitus with 68% cardiovascular disease (CVD)-related mortality. Epidemiological studies suggested inverse correlation between HDL and CVD occurrence. Therefore, low HDL concentration observed in diabetic patients compared to non-diabetic individuals was thought to be one of the primary causes of increased risks of CVD. Efforts to raise HDL level via CETP inhibitors, Torcetrapib and Dalcetrapib, turned out to be disappointing in outcome studies despite substantial increases in HDL-C, suggesting that factors beyond HDL concentration may be responsible for the increased risks of CVD. Therefore, recent studies have focused more on HDL function than on HDL levels. The metabolic environment in diabetes mellitus condition such as hyperglycemia-induced advanced glycation end products, oxidative stress, and inflammation promote HDL dysfunction leading to greater risks of CVD. This review discusses dysfunctional HDL as one of the mechanisms of increased CVD risks in diabetes mellitus through adversely affecting components that support HDL function in cholesterol efflux and LDL oxidation. The dampening of reverse cholesterol transport, a key process that removes cholesterol from lipid-laden macrophages in the arterial wall, leads to increased risks of CVD in diabetic patients. Therapeutic approaches to keep diabetes under control may benefit patients from developing CVD.