bims-obesme 2025-01-26 papers

bims-obesme

Biomed News

on Obesity metabolism

Issue of 2025–01–26
eight papers selected by
Xiong Weng, University of Edinburgh

Homeobox C4 transcription factor promotes adipose tissue thermogenesis.
SLC13A2 promotes hepatocyte metabolic remodeling and liver regeneration by enhancing de novo cholesterol biosynthesis.
Motif distribution and DNA methylation underlie distinct Cdx2 binding during development and homeostasis.
Regulation of UCP1 expression by PPARα and pemafibrate in human beige adipocytes.
Palmitate potentiates the SMAD3-PAI-1 pathway by reducing nuclear GDF15 levels.
KAT6A acetylation drives metabolic adaptation to mediate cellular growth and mitochondrial metabolism through AMPK interaction.
Predicting metabolite response to dietary intervention using deep learning.
Palmitoylation-dependent regulation of GPX4 suppresses ferroptosis.

Diabetes. 2025 Jan 24. pii: db240675. [Epub ahead of print]

Homeobox C4 transcription factor promotes adipose tissue thermogenesis.

Ting Yang, Yuxuan Wang, Hang Li, Fengshou Shi, Siqi Xu, Yingting Wu, Jiaqi Xin, Yi Liu, Mengxi Jiang.

The homeobox (HOX) family has shown potential in adipose development and function, yet the specific HOX proteins fueling adipose thermogenesis remain elusive. In this study, we uncovered the novel function of HOXC4 in stimulating adipose thermogenesis. Our bioinformatic analysis indicated an enrichment of Hoxc4 co-expressed genes in metabolic pathways and linked HOXC4 polymorphisms to metabolic parameters, suggesting its involvement in metabolic regulation. In mouse brown adipose tissue, HOXC4 expression negatively correlated with body weight and positively correlated with Ucp1 expression. Through gain- and loss-of-function experiments in mice, we established that HOXC4 is both sufficient and necessary for adipose thermogenesis, leading to enhanced cold tolerance and protection against diet-induced obesity and insulin resistance. Human and mouse primary adipocyte models further confirmed that the thermogenic activation function of HOXC4 is cell-autonomous. Mechanistically, HOXC4 collaborates with cofactor NCOA1 via its hexapeptide motif to form a transcriptional complex at the Ucp1 promoter, thereby promoting Ucp1 transcription and adipose thermogenesis. These findings delineate a novel mechanism by which HOXC4 drives thermogenic transcription and adipose energy metabolism, offering potential therapeutic targets for obesity-related metabolic disorders.

DOI: https://doi.org/10.2337/db24-0675
EMBO J. 2025 Jan 17.

SLC13A2 promotes hepatocyte metabolic remodeling and liver regeneration by enhancing de novo cholesterol biosynthesis.

Li Shi, Hao Chen, Yuxin Zhang, Donghao An, Mengyao Qin, Wanting Yu, Bin Wen, Dandan He, Haiping Hao, Jing Xiong.

  Metabolic requirements of dividing hepatocytes are prerequisite for liver regeneration after injury. In contrast to transcriptional dynamics during liver repair, its metabolic dependencies remain poorly defined. Here, we screened metabolic genes differentially regulated during liver regeneration, and report that SLC13A2, a transporter for TCA cycle intermediates, is decreased in rapid response to partial hepatectomy in mice and recovered along restoration of liver mass and function. Liver-specific overexpression or depletion of SLC13A2 promoted or attenuated liver regeneration, respectively. SLC13A2 increased cleavage of SREBP2, and expression of cholesterol metabolism genes, including LDLR and HMGCR. Mechanistically, SLC13A2 promotes import of citrate into hepatocytes, serving as building block for ACLY-dependent acetyl-CoA formation and de novo synthesis of cholesterol. In line, the pre-administration of the HMGCR inhibitor lovastatin abolished SLC13A2-mediated liver regeneration. Similarly, ACLY inhibition suppressed SLC13A2-promoted cholesterol synthesis for hepatocellular proliferation and liver regeneration in vivo. In sum, this study demonstrates that citrate transported by SLC13A2 acts as an intermediate metabolite to restore the metabolic homeostasis during liver regeneration, suggesting SLC13A2 as a potential drug target after liver damage.

Keywords:  ATP-citate Lyase; Cell Division; De Novo Cholesterol Synthesis; Metabolic Remodeling; Partial Hepatectomy; TCA Cycle

DOI:  https://doi.org/10.1038/s44318-025-00362-y
Nat Commun. 2025 Jan 22. 16(1): 929

Motif distribution and DNA methylation underlie distinct Cdx2 binding during development and homeostasis.

Alireza Lorzadeh, George Ye, Sweta Sharma, Unmesh Jadhav.

Transcription factors guide tissue development by binding to developmental stage-specific targets and establishing an appropriate enhancer landscape. In turn, DNA and chromatin modifications direct the genomic binding of transcription factors. However, how transcription factors navigate chromatin features to selectively bind a small subset of all the possible genomic target loci remains poorly understood. Here we show that Cdx2-a lineage defining transcription factor that binds distinct targets in developing versus adult intestinal epithelial cells-has a preferential affinity for a non-canonical CpG-containing motif in vivo. A higher frequency of this motif at embryonic Cdx2 targets and methylated state of the CpG during development enables selective Cdx2 binding and activation of developmental enhancers and genes. In adult cells, demethylation at these enhancers prevents ectopic Cdx2 binding, instead directing Cdx2 to its canonical motif without a CpG. This shift in Cdx2 binding facilitates Ctcf and Hnf4 recruitment, establishing super-enhancers during development and homeostatic enhancers in adult cells, respectively. Induced DNA methylation in adult mouse epithelium or cultured cells recruits Cdx2 to developmental targets, promoting corecruitment of partner transcription factors. Thus, Cdx2's differential CpG motif preferences enable it to navigate distinct DNA methylation profiles, activating genes specific to appropriate developmental stages.

DOI: https://doi.org/10.1038/s41467-025-56187-0
Life Sci. 2025 Jan 17. pii: S0024-3205(25)00039-6. [Epub ahead of print] 123406

Regulation of UCP1 expression by PPARα and pemafibrate in human beige adipocytes.

Pierre-Louis Batrow, Christian H Roux, Nadine Gautier, Luc Martin, Brigitte Sibille, Hervé Guillou, Catherine Postic, Dominique Langin, Isabelle Mothe-Satney, Ez-Zoubir Amri.

   AIMS: Thermogenic adipocytes are able to dissipate energy as heat from lipids and carbohydrates through enhanced uncoupled respiration, due to UCP1 activity. PPAR family of transcription factors plays an important role in adipocyte biology. The purpose of this work was to characterize the role of PPARα and pemafibrate in the control of thermogenic adipocyte formation and function.
MATERIALS AND METHODS: We used human multipotent adipose-derived stem cells and primary cultures of stroma-vascular fraction cells, transfected with siRNA against PPARα, differentiated into white or beige adipocytes, by the treatment of rosiglitazone or pemafibrate. The expression of key marker genes of adipogenesis and thermogenesis was determined using RT-qPCR and Western blotting. An RNAseq analysis was also performed.
KEY FINDINGS: We show that inhibition of PPARα mRNA increases UCP1 mRNA and protein expression in beige adipocytes induced by rosiglitazone. Knock-down of PPARα also increases stimulated glycerol release. Pemafibrate, described as a selective PPARα modulator, induces adipogenesis and the expression of UCP1 in the absence of PPARα expression. These effects are inhibited by a specific PPARγ antagonist highly suggesting that the pemafibrate effects in adipogenesis and beiging were mediated by PPARγ.
SIGNIFICANCE: Conversion of white into thermogenic adipocytes is mainly due to the activation of PPARγ. Moreover, we show that PPARα seems to act as a hindrance for PPARγ-dependent beiging. Our data question the role of PPARα in human adipocyte browning and the specificity of pemafibrate in adipocytes.

Keywords:  Beige adipocyte; PPARα; PPARγ; Pemafibrate; UCP1; White adipocyte

DOI:  https://doi.org/10.1016/j.lfs.2025.123406
Cell Mol Life Sci. 2025 Jan 18. 82(1): 43

Palmitate potentiates the SMAD3-PAI-1 pathway by reducing nuclear GDF15 levels.

Marta Montori-Grau, Emma Barroso, Javier Jurado-Aguilar, Mona Peyman, Walter Wahli, Xavier Palomer, Manuel Vázquez-Carrera.

  Nuclear growth differentiation factor 15 (GDF15) reduces the binding of the mothers' against decapentaplegic homolog (SMAD) complex to its DNA-binding elements. However, the stimuli that control this process are unknown. Here, we examined whether saturated fatty acids (FA), particularly palmitate, regulate nuclear GDF15 levels and the activation of the SMAD3 pathway in human skeletal myotubes and mouse skeletal muscle, where most insulin-stimulated glucose use occurs in the whole organism. Human LHCN-M2 myotubes and skeletal muscle from wild-type and Gdf15-/- mice fed a standard (STD) or a high-fat (HFD) diet were subjected to a series of studies to investigate the involvement of lipids in nuclear GDF15 levels and the activation of the SMAD3 pathway. The saturated FA palmitate, but not the monounsaturated FA oleate, increased the expression of GDF15 in human myotubes and, unexpectedly, decreased its nuclear levels. This reduction was prevented by the nuclear export inhibitor leptomycin B. The decrease in nuclear GDF15 levels caused by palmitate was accompanied by increases in SMAD3 protein levels and in the expression of its target gene SERPINE1, which encodes plasminogen activator inhibitor 1 (PAI-1). HFD-fed Gdf15-/- mice displayed aggravated glucose intolerance compared to HFD-fed WT mice, with increased levels of SMAD3 and PAI-1 in the skeletal muscle. The increased PAI-1 levels in the skeletal muscle of HFD-fed Gdf15-/- mice were accompanied by a reduction in one of its targets, hepatocyte growth factor (HGF)α, a cytokine involved in glucose metabolism. Interestingly, PAI-1 acts as a ligand of signal transducer and activator of transcription 3 (STAT3) and the phosphorylation of this transcription factor was exacerbated in HFD-fed Gdf15-/- mice compared to HFD-fed WT mice. At the same time, the protein levels of insulin receptor substrate 1 (IRS-1) were reduced. These findings uncover a potential novel mechanism through which palmitate induces the SMAD3-PAI-1 pathway to promote insulin resistance in skeletal muscle by reducing nuclear GDF15 levels.

Keywords:  GDF15; Insulin resistance; Muscle; Oleate; PAI-1; Palmitate; SMAD3

DOI:  https://doi.org/10.1007/s00018-024-05571-y
bioRxiv. 2025 Jan 14. pii: 2025.01.14.633047. [Epub ahead of print]

KAT6A acetylation drives metabolic adaptation to mediate cellular growth and mitochondrial metabolism through AMPK interaction.

Mariko Aoyagi Keller, Andreas Ivessa, Tong Liu, Hong Li, Peter J Romanienko, Michinari Nakamura.

Diets influence metabolism and disease susceptibility, with lysine acetyltransferases (KATs) serving as key regulators through acetyl-CoA. We have previously demonstrated that a ketogenic diet alleviates cardiac pathology, though the underlying mechanisms remain largely unknown. Here we show that KAT6A acetylation is crucial for mitochondrial function and cell growth. Proteomic analysis revealed that KAT6A is acetylated at lysine (K)816 in the hearts of mice fed a ketogenic diet under hypertension, which enhances its interaction with AMPK regulatory subunits. RNA-sequencing analysis demonstrated that the KAT6A acetylation-mimetic mutant stimulates AMPK signaling in cardiomyocytes. Moreover, the acetylation-mimetic mutant mitigated phenylephrine-induced mitochondrial dysfunction and cardiomyocyte hypertrophy via AMPK activation. However, KAT6A-K816R acetylation-resistant knock-in mice unexpectedly exhibited smaller hearts with enhanced AMPK activity, conferring protection against neurohumoral stress-induced cardiac hypertrophy and remodeling. These findings indicate that KAT6A regulates metabolism and cellular growth by interacting with and modulating AMPK activity through K816-acetylation in a cell type-specific manner.

DOI: https://doi.org/10.1101/2025.01.14.633047
Nat Commun. 2025 Jan 18. 16(1): 815

Predicting metabolite response to dietary intervention using deep learning.

Tong Wang, Hannah D Holscher, Sergei Maslov, Frank B Hu, Scott T Weiss, Yang-Yu Liu.

Due to highly personalized biological and lifestyle characteristics, different individuals may have different metabolite responses to specific foods and nutrients. In particular, the gut microbiota, a collection of trillions of microorganisms living in the gastrointestinal tract, is highly personalized and plays a key role in the metabolite responses to foods and nutrients. Accurately predicting metabolite responses to dietary interventions based on individuals' gut microbial compositions holds great promise for precision nutrition. Existing prediction methods are typically limited to traditional machine learning models. Deep learning methods dedicated to such tasks are still lacking. Here we develop a method McMLP (Metabolite response predictor using coupled Multilayer Perceptrons) to fill in this gap. We provide clear evidence that McMLP outperforms existing methods on both synthetic data generated by the microbial consumer-resource model and real data obtained from six dietary intervention studies. Furthermore, we perform sensitivity analysis of McMLP to infer the tripartite food-microbe-metabolite interactions, which are then validated using the ground-truth (or literature evidence) for synthetic (or real) data, respectively. The presented tool has the potential to inform the design of microbiota-based personalized dietary strategies to achieve precision nutrition.

DOI: https://doi.org/10.1038/s41467-025-56165-6
Nat Commun. 2025 Jan 20. 16(1): 867

Palmitoylation-dependent regulation of GPX4 suppresses ferroptosis.

Bin Huang, Hui Wang, Shuo Liu, Meng Hao, Dan Luo, Yi Zhou, Ying Huang, Yong Nian, Lei Zhang, Bo Chu, Chengqian Yin.

S-palmitoylation is a reversible and widespread post-translational modification, but its role in the regulation of ferroptosis has been poorly understood. Here, we elucidate that GPX4, an essential regulator of ferroptosis, is reversibly palmitoylated on cysteine 66. The acyltransferase ZDHHC20 palmitoylates GPX4 and increases its protein stability. ZDHHC20 depletion or inhibition of protein palmitoylation by 2-BP sensitizes cancer cells to ferroptosis. Moreover, we identify APT2 as the depalmitoylase of GPX4. Genetic silencing or pharmacological inhibition of APT2 with ML349 increases GPX4 palmitoylation, thereby stabilizing the protein and conferring resistance to ferroptosis. Notably, disrupting GPX4 palmitoylation markedly potentiates ferroptosis in xenografted and orthotopically implanted tumor models, and inhibits tumor metastasis through blood vessels. In the chemically induced colorectal cancer model, knockout of APT2 significantly aggravates cancer progression. Furthermore, pharmacologically modulating GPX4 palmitoylation impacts liver ischemia-reperfusion injury. Overall, our findings uncover the intricate network regulating GPX4 palmitoylation, highlighting its pivotal role in modulating ferroptosis sensitivity.

DOI: https://doi.org/10.1038/s41467-025-56344-5