Acute hyperbaric stress during diving combines increased ambient pressure, hyperoxia, hemodynamic shifts, and often muscular workload. Identifying real-time blood biomarkers sensitive to these individual and combined physiological loads remains a challenge. Neuregulin-4 (NRG4), an adipokine secreted by thermogenic and subcutaneous white fat, responds to adrenergic stimulation and modulates redox homeostasis. We investigated NRG4 dynamics alongside oxidative protein carbonyls in divers in warm (thermoneutral) water (∼33.6 °C ambient water temperature) to avoid cold stress. Two field campaigns were conducted: a first depth response campaign involved divers exposed to 20, 30, or 40 m on separate days, without exercise, with serial blood sampling; a second physical effort study involved 15 m dives with or without slow-pedalling exercise. Serum NRG4 was quantified by ELISA and expressed as log2 fold change relative to baseline. Protein carbonyls were measured as markers of oxidative damage. Statistical analysis employed single-sample tests and false-discovery rate control. NRG4 exhibited a robust early increase at 30 m, significant after correction, and nominal elevations at 40 m, but remained unchanged at 20 m. Exercise at 15 m triggered a significant early NRG4 rise absent during passive dives at the same depth. Protein carbonyls remained stable in early post-emersion windows but increased significantly at later time points (180- and 240-min post-emersion) following dives to 40 m, indicating delayed oxidative burden. Our findings position NRG4 as a fast, pressure- and workload-responsive biomarker of diving stress, temporally distinct from classical oxidative injury markers that manifest later. This temporal dissociation underscores the potential of NRG4 for real-time monitoring of acute physiological load during hyperbaric exposure, integrating pressure- and workload-related stressors.

Preclinical models implicate the parathyroid hormone/parathyroid-hormone-related protein (PTH/PTHrP)-PTH1 receptor (PTH1R) axis in adipocyte lipolysis, adipose browning, and energy wasting. Whether this catabolic program is reproduced in vivo in humans remains unresolved. Primary hyperparathyroidism (PHPT), a condition of chronic endogenous PTH excess, provides a clinically relevant model to test the translational relevance of this pathway.

Cancer-associated cachexia (CAC) is a multifactorial wasting syndrome characterized by progressive loss of fat and lean mass, systemic inflammation, and poor therapeutic responsiveness. While brown adipose tissue (BAT) is traditionally considered a protective, energy-dissipating organ, its qualitative remodeling in CAC remains poorly characterized.Here, we demonstrate that CAC induces a senescent conversion of BAT, marked by thermogenic failure, fibrosis, inflammation, and acquisition of a senescence-associated secretory phenotype (SASP). Through integrative transcriptomic, proteomic, and secretomic analyses in a murine model of lung cancer-induced cachexia, we identify S100A9 as a key factor selectively upregulated and secreted by brown adipocytes. Functional assays reveal that the BAT secretome exerts deleterious paracrine effects on white adipocytes and skeletal myotubes, promoting lipolysis and atrophy, while also impairing brown adipocyte identity in an autocrine manner. Co-culture and gain-of-function experiments with S100A9 recapitulate these phenotypes in vitro in mouse and human brown adipocytes, whereas pharmacological blockade of S100A9 signaling partially restores thermogenic and metabolic features. Collectively, our findings reveal that BAT undergoes functional reprogramming into a senescent and secretory tissue in cancer cachexia, with adipocyte-derived S100A9 acting as a novel pro-cachectic mediator. This work redefines the role of BAT in CAC and identifies S100A9 as a potential therapeutic target within the adipose-muscle crosstalk.

Cervical cancer is one of the leading causes of tumor-related deaths among women. Chemotherapy in cervical cancer is mainly based on cisplatin, but this drug has limited efficacy; therefore, alternative treatment options are needed. Ferroptosis represents a novel form of cell death. In cervical epithelium, ferroptosis occurs in the early neoplastic stages of papillomavirus infection but shifts to evasion in carcinoma. Combination therapy has the potential to enhance cancer cell death and overcome resistance development. Herein we demonstrate that dimethyl fumarate (DMF), a Food and Drug Administration (FDA)-approved anti-inflammatory drug, induces ferroptosis in cervical cancer cells in a dose-dependent manner and inhibits growth in spheroid models. Cotreatment with DMF and cisplatin significantly decreases cell viability compared to either drug alone. Under DMF/cisplatin combination, cervical cancer cells underwent to glutathione depletion and p53 (re)activation, leading to cell death by both ferroptosis and apoptosis. We found a p53-mediated downregulation of the Solute Carrier Family 7 Member 11 (SLC7A11)/Cystine/Glutamate Transporter (xCT) expression and glutathione levels. Our results suggest that combined administration of DMF and cisplatin, by targeting the dependency of cervical cancer cells on glutathione and (re)activating p53, represents a promising anticancer therapeutic strategy.

Psoriasis is a chronic immune-mediated inflammatory disease with systemic manifestations beyond the skin, yet the role of subcutaneous adipose tissue (SAT) in disease biology and therapeutic response remains poorly understood. Here, we investigated inflammatory features of SAT in psoriasis and the effects of dimethyl fumarate (DMF) on this compartment. Six adults with moderate-to-severe plaque psoriasis received oral DMF for 24 weeks and were clinically evaluated measuring the Psoriasis Area and Severity Index (PASI), showing a consistent reduction in disease severity during treatment. Publicly available spatial transcriptomic data were analysed to profile inflammatory signatures in SAT clusters of psoriatic versus healthy skin. Bulk RNA sequencing was performed on SAT biopsies obtained from psoriatic plaques before and after DMF treatment in four patients. Complementary in vitro models using murine 3T3-L1 adipocytes and human adipocytes differentiated from mesenchymal stem cells were exposed to pro-inflammatory cytokines or macrophage-conditioned media (CM) with or without DMF to assess effects on inflammatory gene expression and NF-κB signalling. Spatial transcriptomics identified enrichment of inflammation-related pathways in SAT beneath psoriatic lesions. DMF treatment was associated with reduced expression of inflammatory mediators and with a shift in SAT transcriptional profile toward patterns observed in healthy tissue. In vitro, DMF significantly attenuated cytokine- and CM-induced adipocyte activation and reduced NF-κB phosphorylation in both murine and human adipocyte models. These data provide integrated clinical and experimental evidence that DMF treatment is associated with reduced disease activity and attenuation of inflammatory signalling within psoriatic SAT, supporting adipose tissue as a potentially modifiable inflammatory compartment in psoriasis.

Intercellular mitochondria transfer is an evolutionarily conserved process in which one cell delivers some of their mitochondria to another cell in the absence of cell division. This process has diverse functions depending on the cell types involved and physiological or disease context. Although mitochondria transfer was first shown to provide metabolic support to acceptor cells, recent studies have revealed diverse functions of mitochondria transfer, including, but not limited to, the maintenance of mitochondria quality of the donor cell and the regulation of tissue homeostasis and remodelling. Many mitochondria-transfer mechanisms have been described using a variety of names, generating confusion about mitochondria transfer biology. Furthermore, several therapeutic approaches involving mitochondria-transfer biology have emerged, including mitochondria transplantation and cellular engineering using isolated mitochondria. In this Consensus Statement, we define relevant terminology and propose a nomenclature framework to describe mitochondria transfer and transplantation as a foundation for further development by the community as this dynamic field of research continues to evolve. This Consensus Statement provides a nomenclature framework and experimental recommendations for studying mitochondrial transfer and transplantation.

Macrophages are key regulators of adipose tissue plasticity. Obesity impairs brown adipose tissue (BAT) function in humans, yet macrophage-mediated mechanisms remain elusive. Here, we introduce MACanalyzeR, a single-cell RNA sequencing (scRNAseq) tool designed for comprehensive monocyte/macrophage metabolic profiling. Applying MACanalyzeR to BAT from obese male murine models (db/db and HFD-fed mice), we identify lipid-associated macrophages (LAMs) with foamy characteristics. Unlike db/db BAT LAMs, those in HFD BAT correlate with thermogenic gene expression and PPAR signaling activation. A distinct PpargHIGH LAM subcluster progressively accumulates in thermogenically active BAT. Macrophage-specific Pparg depletion disrupts BAT thermogenesis, inducing a white-like phenotype and metabolic dysfunctions. Mechanistically, PpargHIGH LAMs secrete GDF15, a key regulator of BAT identity and lipid metabolism under high-energy demand. Our study establishes MACanalyzeR as a powerful tool for immunometabolic interrogation and identifies PpargHIGH LAMs as critical mediators of BAT homeostasis.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the selective loss of motor neurons. The contribution of peripheral organs remains incompletely understood. We focused our attention on brown adipose tissue (BAT) and its secreted extracellular vesicles (EVs) given their role in regulating systemic energy balance. In this study, we employed a multi-omics approach, including RNA sequencing (GEO identifier GSE273052) and proteomics (ProteomeXchange identifier PXD054147), to investigate the alterations in BAT and its EVs in the SOD1-G93A mouse model of ALS. Our results revealed consistent changes in the proteomic and transcriptomic profiles of BAT from SOD1-G93A mice, highlighting alterations such as mitochondrial dysfunction and impaired differentiation capacity. Specifically, primary brown adipocytes (PBAs) from SOD1-G93A mice exhibited differentiation impairment, respiratory defects, and alterations in mitochondrial dynamics. Furthermore, the BAT-derived EVs from SOD1-G93A mice displayed distinct changes in size distribution and cargo content. In parallel, such EVs negatively impacted the differentiation and homeostasis of C2C12 murine myoblasts, as well as induced atrophy in C2C12-derived myotubes. These findings suggest that BAT undergoes pathological perturbations in ALS mouse model and could impact on skeletal muscle homeostasis through the secretion of dysfunctional EVs.

Macrophages in brown adipose tissue (BAT) play a complex role in regulating its activity. However, the role of macrophages in regulating BAT activation/deactivation has not yet been comprehensively characterized. To elucidate this, we developed MACanalyzeR, a scRNAseq-based tool specifically designed to explore the macrophage features at molecular and metabolic level. MACanalyzeR was applied in scRNA-seq datasets obtained from BAT with thermogenic loss (db/db mice) and activation (High Fat Diet, HFD). Our computational approach revealed that macrophages accumulating in BAT upon these conditions resemble lipid-associated macrophages (LAMs) with foaming-like features. BAT LAMs also show a significant enrichment of genes associated with mitochondria and lysosomes. Interestingly, LAMs identified in BAT from HFD mice positively correlate with thermogenic genes and exhibit an enrichment in PPARγ signaling pathway, with an activated mitochondrial metabolism. Cell dynamic strategy, revealed that LAM with high Pparg expression levels (PpargHIGH) progressively accumulate during skeletal muscle regeneration, suggesting a potential role for this LAM subcluster in maintaining tissue homeostasis. Our findings suggest PpargHIGH LAMs as a subclass of macrophages potentially contributing in preserving tissue homeostasis associated with high energy demand conditions such as thermogenic and regenerative stimuli. ### Competing Interest Statement The authors have declared no competing interest.

Obesity and type 2 diabetes cause a loss in brown adipose tissue (BAT) activity, but the molecular mechanisms that drive BAT cell remodeling remain largely unexplored. Using a multilayered approach, we comprehensively mapped a reorganization in BAT cells. We uncovered a subset of macrophages as lipid-associated macrophages (LAMs), which were massively increased in genetic and dietary model of BAT expansion. LAMs participate in this scenario by capturing extracellular vesicles carrying damaged lipids and mitochondria released from metabolically stressed brown adipocytes. CD36 scavenger receptor drove LAM phenotype, and CD36-deficient LAMs were able to increase brown fat genes in adipocytes. LAMs released transforming growth factor β1 (TGF-β1), which promoted the loss of brown adipocyte identity through aldehyde dehydrogenase 1 family member A1 (Aldh1a1) induction. These findings unfold cell dynamic changes in BAT during obesity and identify LAMs as key responders to tissue metabolic stress and drivers of loss of brown adipocyte identity.

Brown adipose tissue (BAT) is mitochondria rich, enabling high oxidative metabolism for non-shivering thermogenesis. The release of large/small extracellular vesicles (EVs) containing mitochondria or mitochondrial fragments, termed mito-EVs, may support mitochondrial quality control or intercellular communication. We present a protocol to isolate and characterize mito-EVs. We detail steps for BAT processing, cell debris removal, differential centrifugation (dC), and mito-EV analysis by flow cytometry and immunoblotting assays.For complete details on the use and execution of this protocol, please refer to Rosina et al.1

This study aims to obtain a cyto-compatible 3D printable bio-resin for the manufacturing of meshes designed from acquired real patients’ bone defect to be used in future for guided bone regeneration (GBR), achieving the goal of personalized medicine, decreasing surgical, recovery time, and patient discomfort. To this purpose, a biobased, biocompatible, and photo-curable resin made of acrylated epoxidized soybean oil (AESO) diluted with soybean oil (SO) is developed and 3D printed using a commercial digital light processing (DLP) 3D printer. 3D printed samples show good thermal properties, allowing for thermally-based sterilization process and mechanical properties typical of crosslinked natural oils (i.e., E = 12 MPa, UTS = 1.5 MPa), suitable for the GBR application in the oral surgery. The AESO-SO bio-resin proves to be cytocompatible, allowing for fibroblast cells proliferation (viability at 72 h > 97%), without inducing severe inflammatory response when co-cultured with macrophages, as demonstrated by cytokine antibody arrays, that is anyway resolved in the first 24 h. Moreover, accelerated degradation tests prove that the bio-resin is biodegradable in hydrolytic environments.

Biorefinery co-products obtained from biomass of the field isolated diatom Staurosirella pinnata have been investigated for their bioactivity on selected human and murine cell lines. Biomass grown in indoor photobioreactor, collected at the stationary phase, was subjected to methanolic extraction to produce a crude extract, sequentially fractionated (hydrophilic-hydrophobic gradient) to obtain six fractions (A4, A5, A7; B4, B5, B6). Fractions' bioactivity was tested on BRAFwt and BRAFV600E human melanoma cell lines, compared to normal keratinocytes. All fractions showed cytotoxic activity, but only fraction A4 showed a remarkable cell-type selectivity, with cell death induction up to 70 % on melanoma cells. Further characterization allowed to identify and purify four apocarotenoids from fraction A4, representing the first report of such class of compound s in mass cultivated diatoms. In addition, fraction A5 resulted to be a mixture of oxylipins and fraction B4 of purine nucleosides, with adenosine as main component. Residual biomass was further processed to obtain an enriched lipidic extract, characterized by a high content of poly-unsaturated fatty acids. Anti-diabetic and anti-obesity activities were assessed by evaluating the expression levels of key proteins involved into thermogenesis (UCP1), lipolysis (Perilipin, HSL660), and mitochondrial dynamics (pDRP1, VDAC), on murine white adipocyte cell line. Overall, the data here reported confirmed S. pinnata as a platform for the discovery and purification of bioactive compounds with biomedical potential, and the biorefinery pipeline allow their combined isolation, thus advancing the sustainability of diatom exploitation for the discovery and production of bioactive molecules.

Immunometabolism investigates the intricate relationship between the immune system and cellular metabolism. This study delves into the consequences of mitochondrial frataxin (FXN) depletion, the primary cause of Friedreich’s ataxia (FRDA), a debilitating neurodegenerative condition characterized by impaired coordination and muscle control. By using single-cell RNA sequencing, we have identified distinct cellular clusters within the cerebellum of an FRDA mouse model, emphasizing a significant loss in the homeostatic response of microglial cells lacking FXN. Remarkably, these microglia deficient in FXN display heightened reactive responses to inflammatory stimuli. Furthermore, our metabolomic analyses reveal a shift towards glycolysis and itaconate production in these cells. Remarkably, treatment with butyrate counteracts these immunometabolic changes, triggering an antioxidant response via the itaconate-Nrf2-GSH pathways and suppressing the expression of inflammatory genes. Furthermore, we identify Hcar2 (GPR109A) as a mediator involved in restoring the homeostasis of microglia without FXN. Motor function tests conducted on FRDA mice underscore the neuroprotective attributes of butyrate supplementation, enhancing neuromotor performance. In conclusion, our findings elucidate the role of disrupted homeostatic function in cerebellar microglia in the pathogenesis of FRDA. Moreover, they underscore the potential of butyrate to mitigate inflammatory gene expression, correct metabolic imbalances, and improve neuromotor capabilities in FRDA.

Brown adipose tissue (BAT) controls mammalian core body temperature by non-shivering thermogenesis. BAT is extraordinarily rich in mitochondria, which have the peculiarity of generating heat by uncoupled respiration. Since the mitochondrial activity of BAT is subject to cycles of activation and deactivation in response to environmental temperature changes, an integrated mitochondrial quality control (MQC) system is of fundamental importance to ensure BAT physiology. Here, we provide an overview of the conventional and alternative mechanisms through which thermogenic adipocytes selectively remove damaged parts of mitochondria and how macrophages participate in the MQC system by removing extracellular mitochondrial waste to maintain the thermogenic function of BAT.

EDITORIAL article Front. Physiol., 24 January 2023Sec. Integrative Physiology Volume 14 - 2023 | https://doi.org/10.3389/fphys.2023.1145165

Objective: Accumulating evidence suggests that dysfunctional adipose tissue (AT) plays a major role in the risk of developing multiple sclerosis (MS), the most common immune-mediated and demyelinating disease of the central nervous system. However, the contribution of adipose tissue to the etiology and progression of MS is still obscure. This study aimed at deciphering the responses of AT in experimental autoimmune encephalomyelitis (EAE), the best characterized animal model of MS.Results and Methods: We observed a significant AT loss in EAE mice at the onset of disease, with a significant infiltration of M1-like macrophages and fibrosis in the AT, resembling a cachectic phenotype. Through an integrative and multilayered approach, we identified lipocalin2 (LCN2) as the key molecule released by dysfunctional adipocytes through redox-dependent mechanism. Adipose-derived LCN2 shapes the pro inflammatory macrophage phenotype, and the genetic deficiency of LCN2 specifically in AT reduced weight loss as well as inflammatory macrophage infiltration in spinal cord in EAE mice. Mature adipocytes downregulating LCN2 reduced lipolytic response to inflammatory stimuli (e.g. TNFa) through an ATGL-mediated mechanism.Conclusions: Overall data highlighted a role LCN2 in exacerbating inflammatory phenotype in EAE model, suggesting a pathogenic role of dysfunctional AT in MS.& COPY; 2023 The Author(s). Published by Elsevier GmbH. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).