IGF-1 prevents high glucose-induced cell cycle arrest in cardiomyocytes via β-catenin pathway

Targeting cardiomyocyte proliferation as a key approach of promoting heart repair after injury

Cardiovascular diseases such as myocardial infarction (MI) is a major contributor to human mortality and morbidity. The mammalian adult heart almost loses its plasticity to appreciably regenerate new cardiomyocytes after injuries, such as MI and heart failure. The neonatal heart exhibits robust proliferative capacity when exposed to varying forms of myocardial damage. The ability of the neonatal heart to repair the injury and prevent pathological left ventricular remodeling leads to preserved or improved cardiac function. Therefore, promoting cardiomyocyte proliferation after injuries to reinitiate the process of cardiomyocyte regeneration, and suppress heart failure and other serious cardiovascular problems have become the primary goal of many researchers. Here, we review recent studies in this field and summarize the factors that act upon the proliferation of cardiomyocytes and cardiac repair after injury and discuss the new possibilities for potential clinical treatment strategies for cardiovascular diseases.

Knockdown of DNA-binding protein A enhances the chemotherapy sensitivity of colorectal cancer via suppressing the Wnt/β-catenin/Chk1 pathway

DNA-binding protein A (dbpA) is reported to be upregulated in many cancers and associated with tumor progress. The present study aimed to investigate the role of dbpA in 5-fluorouracil (5-FU)-resistant and oxaliplatin (L-OHP)-resistant colorectal cancer (CRC) cells. We found that 5-FU and L-OPH treatment promoted the expression of dbpA. Enhanced dbpA promoted the drug resistance of SW620 cells to 5-FU and L-OHP. DbpA knockdown inhibited cell proliferation, induced cell apoptosis, and cell cycle arrested in SW620/5-FU and SW620/L-OHP cells. Besides, dbpA short hairpin RNA (shRNA) enhanced the cytotoxicity of 5-FU and L-OHP to SW620/5-FU and SW620/L-OHP cells. Meanwhile, dbpA shRNA inhibited the activation of the Wnt/β-catenin pathway that induced by 5-FU stimulation in SW620/5-FU cells. Activation of the Wnt/β-catenin pathway or overexpression of checkpoint kinase 1 (Chk1) abrogated the promoting effect of dbpA downregulation on 5-FU sensitivity of CRC cells. Importantly, downregulation of dbpA suppressed tumor growth and promoted CRC cells sensitivity to 5-FU in vivo. Our study indicated that the knockdown of dbpA enhanced the sensitivity of CRC cells to 5-FU via Wnt/β-catenin/Chk1 pathway, and DbpA may be a potential therapeutic target to sensitize drug resistance CRC to 5-FU and L-OHP.

High-Intensity Interval Training Reversed High-Fat Diet-Induced M1-Macrophage Polarization in Rat Adipose Tissue via Inhibition of NOTCH Signaling

Introduction

There is accumulating evidence on the beneficial effect of exercise intervention in the management of metabolic disorders; however, the molecular mechanism is still unclear. Here, the current study aimed to compare the effect of high-intensity interval training (HIIT) and continuous endurance training (CET) on serum and adipose-tissue markers of M1/M2 macrophage polarization.

Methods

A total of 45 healthy male Wistar rats were divided into groups of normal chow (n=10) and high-fat diet (HFD) (n=35). Then, rats receiving the HFD were randomly divided into four groups. Training programs were performed for 5 days/week over 10 weeks. The CET protocol included 30 minutes running at 50%–60% of VO_2max. The HIIT protocol consisted of five repeated intervals of 2-minute sprints on the treadmill at 80%–90% VO_2max workload with 1 minute's 30%–35% VO_2max interval for each rat. Then, biochemical parameters were assessed. Macrophage-polarization markers were assessed at mRNA and protein levels by real-time PCR and Western blotting, respectively.

Results

Both exercise-training programs, especially HIIT, reversed increased serum biochemical parameters (glucose, triglycerides, cholesterol, Homeostatic Model Assessment of Insulin Resistance, and hsCRP), M1-polarization markers (circulating IL6, TNFα, and adipose-tissue mRNA expression of IL6, TNFα and iNOS), M2 markers (CD206, CD163, and IL10 expression), as well as pIκKB, pNFκB, and NICD expression in HFD-induced diabetes.

Conclusion

Our findings suggest that despite devoting less time, the HIIT workout is a more effective intervention for diabetes management. Moreover, HIIT reverses HFD-induced macrophage polarization by targeting the NFκB and NOTCH signaling pathways.