Research Note: Effect of selection for body weight on the adipogenic conversion of turkey myogenic satellite cells by Syndecan-4 and its covalently attached N-glycosylation chains

Post-translational regulation of muscle growth, muscle aging and sarcopenia

Skeletal muscle makes up 30-40% of the total body mass. It is of great significance in maintaining digestion, inhaling and exhaling, sustaining body posture, exercising, protecting joints and many other aspects. Moreover, muscle is also an important metabolic organ that helps to maintain the balance of sugar and fat. Defective skeletal muscle function not only limits the daily activities of the elderly but also increases the risk of disability, hospitalization and death, placing a huge burden on society and the healthcare system. Sarcopenia is a progressive decline in muscle mass, muscle strength and muscle function with age caused by environmental and genetic factors, such as the abnormal regulation of protein post-translational modifications (PTMs). To date, many studies have shown that numerous PTMs, such as phosphorylation, acetylation, ubiquitination, SUMOylation, glycosylation, glycation, methylation, S-nitrosylation, carbonylation and S-glutathionylation, are involved in the regulation of muscle health and diseases. This article systematically summarizes the post-translational regulation of muscle growth and muscle atrophy and helps to understand the pathophysiology of muscle aging and develop effective strategies for diagnosing, preventing and treating sarcopenia.

Serum syndecan-4 is associated with nonalcoholic fatty liver disease

OBJECTIVES

The accelerated shedding of extracellular domains of syndecan-4 (SDC4) is associated with central obesity and insulin resistance, while the association between serum SDC4 and nonalcoholic fatty liver disease (NAFLD) is unknown. We aimed to examine the association between SDC4 and NAFLD.

METHODS

Adults undergoing a health examination from 1 June 2019 to 31 December 2019 were enrolled. A diagnosis of NAFLD was made with an abdominal ultrasound. Logistic regression models and the receiver operating characteristic (ROC) curves were used to evaluate the role of SDC4 in predicting NAFLD.

RESULTS

In total, 533 eligible participants were finally enrolled, among them 157 (29.46%) had NAFLD. The proportion of patients with NAFLD increased with the increasing quartiles of serum SDC4. With the increase of serum SDC4 levels, metabolic features including waist circumference, serum triglyceride, total cholesterol, fasting blood glucose, fasting insulin and homeostasis model assessment of insulin resistance were significantly increased. SDC4 was an independent factor for NAFLD (odds ratio 1.963, 95% confidence interval [CI] 1.628-2.367, P < 0.001). The area under the ROC curve of SDC4 for predicting NAFLD was 0.934 (95% CI 0.910-0.959). The optimal cut-off value was 6.575 ng/mL at Youden's index of 0.767. SDC4 had the highest diagnostic sensitivity (84.1%), positive predictive value (82.5%), negative predictive value (93.3%) and positive likelihood ratio (11.356) among all the variables.

CONCLUSIONS

Elevated serum SDC4 level is associated with metabolic disorders and the prevalence of NAFLD among general population. Serum SDC4 may serve as a biomarker of NAFLD.