Transcriptome-Based Identification of the Muscle Tissue-Specific Expression Gene CKM and Its Regulation of Proliferation, Apoptosis and Differentiation in Chicken Primary Myoblasts.

Skeletal muscle is an essential tissue in meat-producing animals, and meat-producing traits have been a hot topic in chicken genetic breeding research. Current research shows that creatine kinase M-type-like (CKM) is one of the most abundant proteins in skeletal muscle and plays an important role in the growth and development of skeletal muscle, but its role in the development of chicken skeletal muscle is still unclear. Via RNA sequencing (RNA-seq), we found that CKM was highly expressed in chicken breast muscle tissue. In this study, the expression profile of CKM was examined by quantitative real-time PCR (qPCR), and overexpression and RNA interference techniques were used to explore the functions of CKM in the proliferation, apoptosis and differentiation of chicken primary myoblasts (CPMs). It was shown that CKM was specifically highly expressed in breast muscle and leg muscle and was highly expressed in stage 16 embryonic muscle, while CKM inhibited proliferation, promoted the apoptosis and differentiation of CPMs and was involved in regulating chicken myogenesis. Transcriptome sequencing was used to identify genes that were differentially expressed in CPMs after CKM disruption, and bioinformatics analysis showed that CKM was involved in regulating chicken myogenesis. In summary, CKM plays an important role in skeletal muscle development during chicken growth and development.

Elevated CD14++CD16+ Monocytes in Hyperhomocysteinemia-Associated Insulin Resistance in Polycystic Ovary Syndrome.

BACKGROUND: Hyperhomocysteinemia, chronic low-grade inflammation, and insulin resistance are predominant features in women with polycystic ovary syndrome (PCOS). CD14++CD16+ inflammatory monocytes are elevated in cardiovascular diseases and diabetes, in which inflammation is one of the pathogenesis. We aimed to determine whether homocysteine levels are associated with monocyte subtypes or insulin resistance in women with PCOS. METHODS: A cross-sectional study was conducted between December 2014 and June 2015 at Peking University Third Hospital. Among 196 Chinese patients with PCOS enrolled, 102 had homocysteine levels ≥10 µmol/L and 94 exhibited normal homocysteine levels. Monocyte surface markers and related cytokines were detected in peripheral blood samples using a flow cytometry, and data on insulin resistance and homocysteine levels were collected. RESULTS: Our results showed that fasting insulin and homeostasis model assessment indices that reflect the severity of insulin resistance were increased in the hyperhomocysteinemia PCOS group. Simple linear regression analysis revealed that homocysteine level is one of the influence factors of insulin resistance in PCOS. Compared with the normal homocysteine group, patients with hyperhomocysteinemia had increased numbers of CD14++CD16+ inflammatory monocyte in their peripheral blood and elevated plasma levels of interleukin-1ß and interleukin-6, 2 typical cytokines secreted by the inflammatory monocytes. Unlike CD14+CD16++ nonclassical monocytes, CD14++CD16+ inflammatory monocytes are characterized by high expression of Human leukocyte antigen-antigen D related (HLA-DR). CONCLUSIONS: Our findings indicate that CD14++CD16+ inflammatory monocytes are associated with hyperhomocysteinemia and insulin resistance in patients with PCOS. Notably, CD14++CD16+ monocytes may contribute to the pathogenesis of insulin resistance in women with PCOS.

Hyperhomocysteinemia Promotes Insulin Resistance and Adipose Tissue Inflammation in PCOS Mice Through Modulating M2 Macrophage Polarization via Estrogen Suppression.

It has been shown that serum homocysteine (Hcy) levels are higher in women with polycystic ovary syndrome (PCOS). However, the specific role of hyperhomocysteinemia (HHcy) in the development of PCOS has never been reported. Adipose tissue inflammation is featured by the infiltration of macrophages, which plays a critical role in the pathogenesis of glucose and insulin intolerance. In this study, C57BL/6 mice were treated with dehydroepiandrosterone (DHEA) and/or a high methionine diet to induce PCOS and HHcy mice models. We showed that DHEA induced a PCOS-like phenotypes, irregular estrous cycles, weight gain, abnormal sex hormone production, glucose and insulin resistance, and polycystic ovaries. HHcy further intensified the effects DHEA on the metabolic, endocrinal, hormonal, and morphological changes in PCOS-like mice. In addition, HHcy attenuated the DHEA-induced increase in serum estrogen levels in mice. Furthermore, HHcy may exacerbate the insulin resistance in PCOS-like mice, most likely through modulating the macrophage M1/M2 polarization pathways via the suppression of estrogen. Most important, our clinical data showed that there were increases in serum Hcy levels in patients with PCOS. These findings deepen our understanding of the pathological roles of HHcy in the development of PCOS and provide a promising target for PCOS therapy in clinical application.