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G protein-coupled receptors (GPCRs) modulate the function of adipose tissue (AT) in general and of adipocytes, specifically. Although it is well-established that GPCRs are widely expressed in AT, their repertoire as well as their regulation and function in (patho)physiological conditions (e.g., obesity) is not fully resolved. Here, we established FATTLAS, an interactive public database, for improved access and analysis of RNA-seq data of mouse and human AT. After extracting the GPCRome of non-obese and obese individuals, highly expressed and differentially regulated GPCRs were identified. Exemplarily, we describe four receptors (GPR146, MRGPRF, FZD5, PTGER2) and analyzed their functions in a (pre)adipocyte cell model. Besides all receptors being involved in adipogenesis, MRGPRF is essential for adipocyte viability and regulates cAMP levels, while GPR146 modulates adipocyte lipolysis via constitutive activation of Gi proteins. Taken together, by implementing and using FATTLAS we describe four hitherto unrecognized GPCRs associated with AT function and adipogenesis.
© 2023 The Author(s).

FBXO28 is a member of F-box proteins that are the substrate receptors of SCF (SKP1, CULLIN1, F-box protein) ubiquitin ligase complexes. Despite the implications of its role in cancer, the function of FBXO28 in epithelial-mesenchymal transition (EMT) process and metastasis for cancer remains largely unknown. Here, we report that FBXO28 is a critical negative regulator of migration, invasion and metastasis in human hepatocellular carcinoma (HCC) in vitro and in vivo. FBXO28 expression is upregulated in human epithelial cancer cell lines relative to mesenchymal counterparts. Mechanistically, by directly binding to SNAI2, FBXO28 functions as an E3 ubiquitin ligase that targets the substrate for degradation via ubiquitin proteasome system. Importantly, we establish a cooperative function for PKA in FBXO28-mediated SNAI2 degradation. In clinical HCC specimens, FBXO28 protein levels positively whereas negatively correlate with PKAα and SNAI2 levels, respectively. Low FBXO28 or PRKACA expression is associated with poor prognosis of HCC patients. Together, these findings elucidate the novel function of FBXO28 as a critical inhibitor of EMT and metastasis in cancer and provide a mechanistic rationale for its candidacy as a new prognostic marker and/or therapeutic target in human aggressive HCC.
© 2023. The Author(s).

Sodium perturbs mitochondrial respiration and induces dysfunctional Tregs.

In Cell Metabolism on 7 February 2023 by Côrte-Real, B. F., Hamad, I., et al.

FOXP3+ regulatory T cells (Tregs) are central for peripheral tolerance, and their deregulation is associated with autoimmunity. Dysfunctional autoimmune Tregs display pro-inflammatory features and altered mitochondrial metabolism, but contributing factors remain elusive. High salt (HS) has been identified to alter immune function and to promote autoimmunity. By investigating longitudinal transcriptional changes of human Tregs, we identified that HS induces metabolic reprogramming, recapitulating features of autoimmune Tregs. Mechanistically, extracellular HS raises intracellular Na+, perturbing mitochondrial respiration by interfering with the electron transport chain (ETC). Metabolic disturbance by a temporary HS encounter or complex III blockade rapidly induces a pro-inflammatory signature and FOXP3 downregulation, leading to long-term dysfunction in vitro and in vivo. The HS-induced effect could be reversed by inhibition of mitochondrial Na+/Ca2+ exchanger (NCLX). Our results indicate that salt could contribute to metabolic reprogramming and that short-term HS encounter perturb metabolic fitness and long-term function of human Tregs with important implications for autoimmunity.
Copyright © 2023 Elsevier Inc. All rights reserved.

BYHW Decoction Improves Cognitive Impairments in Rats with Cerebral Microinfarcts via Activation of the PKA/CREB Pathway.

In Oxidative Medicine and Cellular Longevity on 10 January 2023 by Xue, B., Ma, B., et al.

Cerebral microinfarcts (CMIs) are characterized by sporadic obstruction of small vessels leading to neurons death. They are associated with increased risk of cognitive impairments and may have different risk factors compared with macroinfarcts. CMIs have a high incidence and result in heavy social burden; thus, it is essential to provide reasonable treatment in clinical practice. However, there are relatively few researches on the mechanism and treatment of CMIs, and the literature is composed almost exclusively of community-or hospital based on autopsy or imageological studies focusing on elderly patients. The Bu Yang Huan Wu (BYHW) decoction, a traditional Chinese herbal formula, has long been used to treat stroke and stroke-related diseases, including cognitive impairments. We applied microsphere-induced CMI model in rats to investigate the behavioral and molecular consequences of CMIs and to determine how they were ameliorated by BYHW decoction treatment. We then used the Morris water maze, quantitative proteomics, immunohistochemistry, and other molecular assays and found that activation of the PKA/CREB pathway by BYHW decoction treatment may reverse mitochondrial dysfunction, inhibit apoptosis of hippocampal neurons, and ameliorate CMI-induced cognitive impairments in rats. Collectively, these findings confirmed the therapeutic potential of the BYHW decoction in treating cognitive impairments induced by CMIs and demonstrated a viable mechanism for its action.
Copyright © 2022 Bingjie Xue et al.

Identification of druggable host dependency factors shared by multiple SARS-CoV-2 variants of concern

Preprint on BioRxiv : the Preprint Server for Biology on 9 January 2023 by Frasson, I., Diamante, L., et al.

The high mutation rate of SARS-CoV-2 leads to emergence of several variants, some of which are resistant to vaccines and drugs targeting viral elements. Targeting host dependency factors – cell proteins required for viral replication - would help avoid resistance. However, whether different SARS-CoV-2 variants induce conserved cell responses and exploit the same core host factors is still unclear. We compared three variants of concern and observed that the host transcriptional response was conserved, differing only in kinetics and magnitude. By CRISPR screening we identified the host genes required for infection by each variant: most of the identified genes were shared by multiple variants, both in lung and colon cells. We validated our hits with small molecules and repurposed FDA-approved drugs. All drugs were highly effective against all tested variants, including delta and omicron, new variants that emerged during the study. Mechanistically, we identified ROS production as a pivotal step in early virus propagation. Antioxidant drugs, such as N-acetyl cysteine (NAC), were effective against all variants both in human lung cells, and in a humanised mouse model. Our study supports the use of available antioxidant drugs, such as NAC, as a general and effective anti-COVID-19 approach.

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