Augmented CCL5/CCR5 signaling in brown adipose tissue inhibits adaptive thermogenesis and worsens insulin resistance in obesity

Stratification and prognostic evaluation of breast cancer subtypes defined by obesity-associated genes

OBJECTIVE

Breast cancer was the most common type of cancer among women worldwide, significantly impacting their quality of life and survival rates. And obesity has been widely accepted as an important risk factor for breast cancer. However, the specific mechanisms by which obesity affects breast cancer were still unclear. Therefore, studying the impact mechanisms of obesity as a risk factor for breast cancer was of utmost importance.

METHODS

This study was based on TCGA breast cancer RNA transcriptomic data and the GeneCard obesity gene set. Through single and multiple factor Cox analysis and LASSO coefficient screening, seven hub genes were identified. The independent mechanisms of these seven hub genes were evaluated from various aspects, including survival data, genetic mutation data, single-cell sequencing data, and immune cell data. Additionally, the risk prognosis model and the neural network diagnostic model were established to further investigate these seven hub genes. In order to achieve precision treatment for breast cancer (BRCA), based on the RNA transcriptomic data of the seven genes, 1226 BRCA patients were divided into two subtypes: BRCA subtype 1 and BRCA subtype 2. By studying and comparing the immune microenvironment, investigating the mechanisms of differential gene expression, and exploring the mechanisms of subnetworks, we aim to explore the clinical differences in the presentation of BRCA subtypes and achieve precision treatment for BRCA. Finally, qRT-PCR experiments were conducted to validate the conclusions of the bioinformatics analysis.

RESULTS

The 7 hub genes showed good diagnostic independence and can serve as excellent biomarkers for molecular diagnosis. However, they do not perform well as independent prognostic molecular markers for BRCA patients. When predicting the survival of BRCA patients, their AUC values at 1 year, 3 years, and 5 years are mostly below 0.5. Nevertheless, through the establishment of the risk prognosis model considering the combined effect of the seven hub genes, it was found that the survival prediction of BRCA patients can be significantly improved. The risk prognosis model, compared to the independent use of the seven hub genes as prognostic markers, achieved higher timeROC AUC values at 1 year, 3 years, and 5 years, with values of 0.651, 0.669, and 0.641 respectively. Additionally, the neural network diagnostic model constructed from the 7 genes performs well in diagnosing BRCA, with an AUC value of 0.94, accurately identifying BRCA patients. The two subtypes identified by the seven hub genes exhibited significant differences in survival period, with subtype 1 having a poor prognosis. The differential mechanisms between the two subtypes mainly originate from regulatory differences in the immune microenvironment. Finally, the results of this study's bioinformatics analysis were validated through qRT-PCR experiments.

CONCLUSION

7 hub genes serve as excellent independent biomarkers for molecular diagnosis, and the neural network diagnostic model can accurately distinguish BRCA patients. In addition, based on the expression levels of these seven genes in BRCA patients, two subtypes can be reliably identified: BRCA subtype 1 and BRCA subtype 2, and these two subtypes showed significant differences in BRCA patient survival prognosis, proportion of immune cells, and expression levels of immune cells. Among them, patients with subtype 1 of BRCA had a poor prognosis.

Atractylenolide III from Atractylodes macrocephala Koidz promotes the activation of brown and white adipose tissue through SIRT1/PGC-1α signaling pathway

BACKGROUND

Hypothermia is a complex pathophysiological response that can be life-threatening in low-temperature environment because of impaired thermoregulation. However, there is currently no clinically effective drugs that can prevent or treat this disease. Brown adipose tissue (BAT) activation or browning of white adipose tissue (WAT) is a promising therapeutic strategy to prevent or treat hypothermia. Atractylodes macrocephala Koidz extract (AE) and its active compound Atractylenolide III (AIII) has been reported to regulate glycolipid metabolism, which might be relevant to BAT activation. However, the thermogenic effect and mechanism of AE and AIII on adipose tissues have not been explored yet. Therefore, this study firstly investigated the role of AE and AIII on hypothermia by promoting heat production of BAT and WAT.

PURPOSE

To explore the anti-cold effect of AE and AIII in cold exposure model and explore their biological function and mechanism underlying thermogenesis.

METHODS

The effect of thermogenesis and anti-hypothermia of AE and AIII on C57BL/6J mice were evaluated with several experiment in cold environment, such as toxicity test, cold exposure test, metabolism estimation, histology and immunohistochemistry, and protein expression. Additionally, BAT, inguinal WAT (iWAT) and brown adipocytes were utilized to explore the mechanism of AE and AIII on thermogenesis in vivo and in vitro. Finally, SIRT1 agonist and inhibitor in brown adipocytes to verify that AIII activated BAT through SIRT1/PGC-1α pathway.

RESULTS

Both AE and AⅢ could significantly maintain the core body temperature and body surface temperature of mice during cold exposure. Besides, AE and AⅢ could significantly improve the capacity of total antioxidant and glucose, lipid metabolism of mice. In addition, AE and AIII reduced mitochondrial membrane potential and ATP content both in BAT and brown adipocytes, and decreased the size of lipid droplets. Moreover, AE and AⅢ promoted the expression of proteins related to heat production in BAT and iWAT. And AIII might activate BAT via SIRT1/PGC-1α pathway.

CONCLUSION

AE and AⅢ were potential candidate drugs that treated hypothermia by improving the heat production capacity of the mice. Mechanistically, they may activate SIRT1/PGC-1α pathway, thus enhancing the function of BAT, and promoting the browning of iWAT, to act as anti-hypothermia candidate medicine.

CCL5 mediates breast cancer metastasis and prognosis through CCR5/Treg cells

Background and aims

CCL5 is considered to contribute to the biological function of a variety of cancer types, but its specific mechanism is still unclear. This study aimed to reveal the mechanism of CCL5 in the invasion, metastasis, and prognosis of breast cancer.

Methods

The expression of CCL5 in tumor tissue and serum was measured with a Luminex protein detection kit, and the correlation between CCL5 and clinical parameters was evaluated. Kaplan–Meier analysis was used to analyze the effect of CCL5 on the prognosis of breast cancer patients. Protein interaction network analysis and gene coexpression were used to determine the receptor that has the strongest interaction with CCL5. Enrichment analysis was used to study the possible pathway by which CCL5 affects breast cancer progression. We used immunofluorescence staining and flow cytometry to estimate the fraction of immunity-related components in the tumor microenvironment.

Results

The expression level of CCL5 in breast cancer patients was positively correlated with the degree of axillary lymph node metastasis; CCL5 in tumor tissue was correlated with estrogen receptor status (P = 0.034), progesterone receptor (P = 0.009), nuclear grade (P = 0.013), clinical stage (P < 0.001) and molecular subtype (P = 0.024) in breast cancer patients. Breast cancer patients with high CCL5 expression had worse disease-free survival (P = 0.031) and breast cancer-specific survival (P = 0.043); however, CCL5 had no effect on overall survival (P = 0.077). CCL5 affected tumor progression through CCR5, and the T-cell-related immune pathway may be the main pathway; the CD4+/CD8+, CCR5+/CD4+ and Treg/CCR5+ cell ratios were significantly increased in the lymph node metastasis group.

Conclusion

CCL5 affects the Treg/CD4+CCR5+ cell ratio in breast cancer patients through CCR5, thus affecting breast cancer metastasis and prognosis.

LncRNA and mRNA expression profiles in brown adipose tissue of obesity-prone and obesity-resistant mice

Obesity-prone or obesity-resistant phenotypes can exist in individuals who consume the same diet type. Brown adipose tissue functions to dissipate energy in response to cold exposure or overfeeding. Long noncoding RNAs play important roles in a wide range of biological processes. However, systematic examination of lncRNAs in phenotypically divergent mice has not yet been reported. Here, the lncRNA expression profiles in BAT of HFD-induced C57BL/6J mice were investigated by high-throughput RNA sequencing. Genes that play roles in thermogenesis and related pathways were identified. We found lncRNA (Gm44502) may play a thermogenic role in obesity resistance by interacting with six mRNAs. Our results also indicated that seven differentially expressed lncRNAs (4930528G23Rik, Gm39490, Gm5627, Gm15551, Gm16083, Gm36860, Gm42002) may play roles in reducing heat production in obesity susceptibility by interacting with seven differentially expressed mRNAs. The screened lncRNAs may participate in the pathogenesis of weight regulation and provide insight into obesity therapy.

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First lncRNA profiles in BAT of OR and OP mice via bioinformatic analysis

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Gm44502 may play a thermogenic role by interacting with 6 mRNAs

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7 DElncRNAs may reduce thermogenesis by interacting with 7 DEmRNAs

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Validation of expression changes of candidate genes in BAT by in vivo or in vitro

Inactivation of Type 3 Deiodinase Results in Life-long Changes in the Brown Adipose Tissue Transcriptome in the Male Mouse

Adaptive thermogenesis in small mammals and infants takes place in brown adipose tissue (BAT). Heat is produced via uncoupling protein 1 (UCP1)-mediated uncoupling between oxidation of energy substrates and adenosine 5'-triphosphate synthesis. Thyroid hormone (TH) signaling plays a role in this process. The deiodinases activate thyroxine (T4) to 3,5,3'-triiodothyronine (T3) (D2) or inactivate T4 and T3 to 3,3,5'-triiodothyronine and T2 (D3), respectively. Using a mouse model with selective inactivation of Dio3 in BAT (flox-Dio3 × UCP1-cre = BAT-D3KO), we now show that knocking out D3 resulted in premature exposure of developing brown adipocytes (embryonic days 16.5-18.5) to T3 signaling, leading to an earlier expression of key BAT genes, including Cidea, Cox8b, Dio2, Ucp1, and Pgc1α. Adult BAT-D3KO mice exhibited increased expression of 1591 genes as assessed by RNA sequencing, including 19 gene sets related to mitochondria, 8 related to fat, and 8 related to glucose homeostasis. The expression of 243 genes was changed by more than 1.5-fold, 36 of which play a role in metabolic/thermogenic processes. BAT-D3KO mice weigh less and exhibit smaller white adipocyte area, but maintain normal energy expenditure at room temperature (22 °C) and in the cold (4 °C). They also defend their core temperature more effectively and do not lose as much body weight when exposed to cold. We conclude that the coordinated actions of Dio3 in the embryonic BAT define the timing and intensity of T3 signaling during brown adipogenesis. Enhanced T3 signaling during BAT embryogenesis (Dio3 inactivation) results in selective life-long modifications in the BAT transcriptome.

The Chemokine Systems at the Crossroads of Inflammation and Energy Metabolism in the Development of Obesity

Obesity is characterized as a complex and multifactorial excess accretion of adipose tissue accompanied with alterations in the immune and metabolic responses. Although the chemokine systems have been documented to be involved in the control of tissue inflammation and metabolism, the dual role of chemokines and chemokine receptors in the pathogenesis of the inflammatory milieu and dysregulated energy metabolism in obesity remains elusive. The objective of this review is to present an update on the link between chemokines and obesity-related inflammation and metabolism dysregulation under the light of recent knowledge, which may present important therapeutic targets that could control obesity-associated immune and metabolic disorders and chronic complications in the near future. In addition, the cellular and molecular mechanisms of chemokines and chemokine receptors including the potential effect of post-translational modification of chemokines in the regulation of inflammation and energy metabolism will be discussed in this review.