Metabolic Programming Research Articles

Heme catabolism and heme oxygenase-1-expressing myeloid cells in pathophysiology

Although the pathological significance of myeloid cell heterogeneity is still poorly understood, new evidence indicates that distinct macrophage subsets are characterized by specific metabolic programs that influence disease onset and progression. Within this scenario, distinct subsets of macrophages, endowed with high rates of heme catabolism by the stress-responsive enzyme heme oxygenase-1 (HO-1), play critical roles in physiologic and pathological conditions. Of relevance, the substrates of HO-1 activity are the heme groups that derive from cellular catabolism and are converted into carbon monoxide (CO), biliverdin and Fe2+, which together elicit anti-apoptotic, anti-inflammatory activities and control oxidative damage. While high levels of expression of HO-1 enzyme by specialized macrophage populations (erythrophagocytes) guarantee the physiological disposal of senescent red blood cells (i.e. erythrocateresis), the action of HO-1 takes on pathological significance in various diseases, and abnormal CO metabolism has been observed in cancer, hematological diseases, hypertension, heart failure, inflammation, sepsis, neurodegeneration. Modulation of heme catabolism and CO production is therefore a feasible therapeutic opportunity in various diseases. In this review we discuss the role of HO-1 in different pathological contexts (i.e. cancer, infections, cardiovascular, immune-mediated and neurodegenerative diseases) and highlight new therapeutic perspectives on the modulation of the enzymatic activity of HO-1.

Sustained carbon import supports sugar accumulation and anthocyanin biosynthesis during fruit development and ripening in blueberry (Vaccinium ashei)

Fruit ripening is a highly coordinated process involving molecular and biochemical changes that collectively determine fruit quality. The underlying metabolic programs and their transitions leading to fruit ripening remain largely under-characterized in blueberry (Vaccinium sp.), which exhibits atypical climacteric behavior. In this study, we focused on sugar, acid and anthocyanin metabolism in two rabbiteye blueberry cultivars, Premier and Powderblue, during fruit development and ripening. Concentrations of the three major sugars, sucrose (Suc), glucose (Glc), and fructose (Fru) increased steadily during fruit development leading up to ripening, and increased dramatically by around 2-fold in ‘Premier’ and 2- to 3-fold in ‘Powderblue’ during the final stage of fruit ripening. Starch concentration was very low throughout fruit development in both cultivars indicating that it does not serve the role of a major transitory carbon (C) storage form in blueberry fruit. Together, these patterns indicate continued import of C, likely in the form of Suc, throughout blueberry fruit development. Concentrations of the predominant acids, malate and quinate, decreased during ripening, and may contribute to increased shikimate biosynthesis which, in-turn, allows for downstream phenylpropanoid metabolism leading to anthocyanin synthesis. Consistently, anthocyanin concentrations were highest in fully ripened blue fruit. Weighted gene co-expression network analysis (WGCNA) was performed using a ‘Powderblue’ fruit ripening transcriptome and targeted fruit metabolite concentration data. A ‘dark turquoise’ module positively correlated with sugars and anthocyanins, and negatively correlated with acids (malate, quinate), was identified. Gene Ontology (GO) enrichment analysis of this module identified transcripts related to sugar, acid, and phenylpropanoid metabolism pathways. Among these, increased transcript abundance of a VACUOLAR INVERTASE during ripening was consistent with sugar storage in the vacuole. In general, transcript abundance of the glycolysis pathway genes was upregulated during ripening. The transcript abundance of PHOSPHOENOLPYRUVATE (PEP) CARBOXYKINASE increased during fruit ripening and was negatively correlated with malate concentration, suggesting increased malate conversion to PEP, which supports anthocyanin production during fruit ripening. This was further supported by the co-upregulation of several anthocyanin biosynthesis-related genes. Together, this study provides insights into important metabolic programs, and their underlying gene expression patterns during fruit development and ripening in blueberry.

Early Life Energy Balance: The Development of Infant Energy Expenditure and Intake in the Context of Obesity.

This review aims to provide a summary of the current knowledge on measurement tools and most recent evidence for prenatal and postnatal modulators of energy balance in young infants. The prevention of pediatric obesity depends upon curating the perfect imbalance of energy intake to energy expenditure, taking into consideration the energy needs for healthy growth. We summarize the recent evidence for the programming of fetal and infant metabolism influenced by maternal preconception health, prenatal metabolic milieu, and physical activity behaviors. In the early postnatal environment, caregiver feeding behaviors shape the extent of energy imbalance through dictating quantity and modality of infant energy intake. There are biological and behavioral contributors to improper infant energy imbalance. Furthermore, caregiver and clinician education on overfeeding and clinical tools to prescribe and monitor infant overgrowth are absent. Ultimately, the lack of high-quality and modern research of infant energy expenditure underpins the lack of advancement in clinical guidelines and the needed prevention of pediatric obesity.

Transgelin 2 guards T cell lipid metabolism and antitumour function.

Mounting effective immunity against pathogens and tumours relies on the successful metabolic programming of T cells by extracellular fatty acids1-3. Fatty-acid-binding protein 5 (FABP5) has a key role in this process by coordinating the efficient import and trafficking of lipids that fuel mitochondrial respiration to sustain the bioenergetic requirements of protective CD8+ T cells4,5. However, the mechanisms that govern this immunometabolic axis remain unexplored. Here we report that the cytoskeletal organizer transgelin 2 (TAGLN2) is necessary for optimal fatty acid uptake, mitochondrial respiration and anticancer function in CD8+ T cells. TAGLN2 interacts with FABP5 to facilitate its cell surface localization and function in activated CD8+ T cells. Analyses of ovarian cancer specimens revealed that endoplasmic reticulum (ER) stress responses induced by the tumour microenvironment repress TAGLN2 in infiltrating CD8+ T cells, thereby enforcing their dysfunctional state. Restoring TAGLN2 expression in ER-stressed CD8+ T cells increased their lipid uptake, mitochondrial respiration and cytotoxic capacity. Accordingly, chimeric antigen receptor T cells overexpressing TAGLN2 bypassed the detrimental effects of tumour-induced ER stress and demonstrated therapeutic efficacy in mice with metastatic ovarian cancer. Our study establishes the role of cytoskeletal TAGLN2 in T cell lipid metabolism and highlights the potential to enhance cellular immunotherapy in solid malignancies by preserving the TAGLN2-FABP5 axis.

Decoding Apelin: Its Role in Metabolic Programming, Fetal Growth, and Gestational Complications.

Placental insufficiency and gestational diabetes, which are both serious pregnancy complications, are linked to altered fetal growth, whether restricted or excessive, and result in metabolic dysfunction, hypoxic/oxidative injury, and adverse perinatal outcomes. Although much research has been carried out in this field, the underlying pathogenetic mechanisms have not as yet been fully elucidated. Particularly because of the role it plays in cardiovascular performance, glucose metabolism, inflammation, and oxidative stress, the adipokine apelin was recently shown to be a potential regulator of fetal growth and metabolic programming. This review investigated the numerous biological actions of apelin in utero and aimed to shed more light on its role in fetal growth and metabolic programming. The expression of the apelinergic system in a number of tissues indicates its involvement in many physiological mechanisms, including angiogenesis, cell proliferation, energy metabolism, inflammation, and oxidative stress. Moreover, it appears that apelin has a major function in disorders such as diabetes mellitus, fetal growth abnormalities, fetal hypoxia, and preeclampsia. We herein describe in detail the regulatory effects exerted by the adipokine apelin on fetal growth and metabolic programming while stressing the necessity for additional research into the therapeutic potential of apelin and its mechanisms of action in pregnancy-related disorders.

Therapeutic targeting of differentiation-state dependent metabolic vulnerabilities in diffuse midline glioma

H3K27M diffuse midline gliomas (DMG), including diffuse intrinsic pontine gliomas (DIPG), exhibit cellular heterogeneity comprising less-differentiated oligodendrocyte precursors (OPC)-like stem cells and more differentiated astrocyte (AC)-like cells. Here, we establish in vitro models that recapitulate DMG-OPC-like and AC-like phenotypes and perform transcriptomics, metabolomics, and bioenergetic profiling to identify metabolic programs in the different cellular states. We then define strategies to target metabolic vulnerabilities within specific tumor populations. We show that AC-like cells exhibit a mesenchymal phenotype and are sensitized to ferroptotic cell death. In contrast, OPC-like cells upregulate cholesterol biosynthesis, have diminished mitochondrial oxidative phosphorylation (OXPHOS), and are accordingly more sensitive to statins and OXPHOS inhibitors. Additionally, statins and OXPHOS inhibitors show efficacy and extend survival in preclinical orthotopic models established with stem-like H3K27M DMG cells. Together, this study demonstrates that cellular subtypes within DMGs harbor distinct metabolic vulnerabilities that can be uniquely and selectively targeted for therapeutic gain.

Brown fat ATP-citrate lyase links carbohydrate availability to thermogenesis and guards against metabolic stress.

Brown adipose tissue (BAT) engages futile fatty acid synthesis-oxidation cycling, the purpose of which has remained elusive. Here, we show that ATP-citrate lyase (ACLY), which generates acetyl-CoA for fatty acid synthesis, promotes thermogenesis by mitigating metabolic stress. Without ACLY, BAT overloads the tricarboxylic acid cycle, activates the integrated stress response (ISR) and suppresses thermogenesis. ACLY's role in preventing BAT stress becomes critical when mice are weaned onto a carbohydrate-plentiful diet, while removing dietary carbohydrates prevents stress induction in ACLY-deficient BAT. ACLY loss also upregulates fatty acid synthase (Fasn); yet while ISR activation is not caused by impaired fatty acid synthesis per se, deleting Fasn and Acly unlocks an alternative metabolic programme that overcomes tricarboxylic acid cycle overload, prevents ISR activation and rescues thermogenesis. Overall, we uncover a previously unappreciated role for ACLY in mitigating mitochondrial stress that links dietary carbohydrates to uncoupling protein 1-dependent thermogenesis and provides fundamental insight into the fatty acid synthesis-oxidation paradox in BAT.

Adaptations and metabolic evolution of myzozoan protists across diverse lifestyles and environments.

SUMMARYMyzozoans encompass apicomplexans and dinoflagellates that manifest diverse lifestyles in highly varied environments. They show enormous propensity to employ different metabolic programs and exploit different nutrient resources and niches, and yet, they share much core biology that underlies this evolutionary success and impact. This review discusses apicomplexan parasites of medical significance and the traits and properties they share with non-pathogenic myzozoans. These include the versatility of myzozoan plastids, which scale from fully photosynthetic organelles to the site of very select key metabolic pathways. Pivotal evolutionary innovations, such as the apical complex, have allowed myzozoans to shift from predatory to parasitic and other symbiotic lifestyles multiple times in both apicomplexan and dinoflagellate branches of the myzozoan evolutionary tree. Such traits, along with shared mechanisms for nutrient acquisition, appear to underpin the prosperity of myzozoans in their varied habitats. Understanding the mechanisms of these shared traits has the potential to spawn new strategic interventions against medically and veterinary relevant parasites within this grouping.

Study protocol for a single-arm pilot trial investigating the feasibility of a multimodal digital technology for managing metabolic syndrome in patients with chronic obstructive pulmonary disease

Individuals diagnosed with Chronic Obstructive Pulmonary Disease (COPD) are exposed to an increased risk of metabolic syndrome (MetS), which negatively affects their health outcomes and quality of life. Lifestyle interventions have shown promise in managing MetS. This study outlines the protocol for a web-based multimodal self-care program, Digital Metabolic Rehabilitation, for managing MetS in patients with COPD. The Digital Metabolic Rehabilitation is a single-arm pilot trial that integrates the Canadian Health Advanced by Nutrition and Graded Exercise (CHANGE) Program and a web-based wellness platform. The web-based wellness platform employed in this study is My Viva Plan (MVP)®, which integrates a holistic, multicomponent approach to promote wellness. The intervention will primarily focus on lifestyle changes for patients with COPD. Over 6 months, participants will use the web-based wellness platform and engage in weekly online support group sessions. Fifty patients diagnosed with stage I-II COPD and MetS will participate. Blood tests, anthropometrics, body composition, physical function, muscle strength, physical activity, energy metabolism, quality of life and mental health will be assessed at baseline, 3, and 6 months. The Digital Metabolic Rehabilitation program aims to explore whether a multimodal integrative intervention delivered through a web-based wellness platform can be implemented by patients with COPD with MetS. By combining the expertise of the CHANGE Program with the digital delivery format, the intervention seeks to enhance self-monitoring and foster better self-management practices. The protocol outlines a novel and potentially impactful intervention for managing MetS in patients with COPD.

Functional inversion of circadian regulator REV-ERBα leads to tumorigenic gene reprogramming

Profound functional switch of key regulatory factors may play a major role in homeostasis and disease. Dysregulation of circadian rhythm (CR) is strongly implicated in cancer with mechanisms poorly understood. We report here that the function of REV-ERBα, a major CR regulator of the orphan nuclear receptor subfamily, is dramatically altered in tumors in both its genome binding and functional mode. Loss of CR is linked to a functional inversion of REV-ERBα from a repressor in control of CR and metabolic gene programs in normal tissues to a strong activator in different cancers. Through changing its association from NCoR/HDAC3 corepressor complex to BRD4/p300 coactivators, REV-ERBα directly activates thousands of genes including tumorigenic programs such as MAPK and PI3K-Akt signaling. Functioning as a master transcriptional activator, REV-ERBα partners with pioneer factor FOXA1 and directly stimulates a large number of signaling genes, including multiple growth factors, receptor tyrosine kinases, RASs, AKTs, and MAPKs. Moreover, elevated REV-ERBα reprograms FOXA1 to bind new targets through a BRD4-mediated increase in local chromatin accessibility. Pharmacological targeting with SR8278 diminishes the function of both REV-ERBα and FOXA1 and synergizes with BRD4 inhibitor in effective suppression of tumorigenic programs and tumor growth. Thus, our study revealed a functional inversion by a CR regulator in driving gene reprogramming as an unexpected paradigm of tumorigenesis mechanism and demonstrated a high effectiveness of therapeutic targeting such switch.

Microbiota-derived short chain fatty acids in pediatric health and diseases: from gut development to neuroprotection.

The infant gut microbiota undergoes significant changes during early life, which are essential for immune system maturation, nutrient absorption, and metabolic programming. Among the various microbial metabolites, short-chain fatty acids (SCFAs), primarily acetate, propionate, and butyrate, produced through the fermentation of dietary fibers by gut bacteria, have emerged as critical modulators of host-microbiota interactions. SCFAs serve as energy sources for colonic cells and play pivotal roles in regulating immune responses, maintaining gut barrier integrity, and influencing systemic metabolic pathways. Recent research highlights the potential neuroprotective effects of SCFAs in pediatric populations. Disruptions in gut microbiota composition and SCFA production are increasingly associated with a range of pediatric health issues, including obesity, allergic disorders, inflammatory bowel disease (IBD), and neurodevelopmental disorders. This review synthesizes current knowledge on the role of microbiota-derived SCFAs in pediatric health, emphasizing their contributions from gut development to neuroprotection. It also underscores the need for further research to unravel the precise mechanisms by which SCFAs influence pediatric health and to develop targeted interventions that leverage SCFAs for therapeutic benefits.

8347 EARLY CHILDHOOD GROWTH FOLLOWING PRE-PREGNANCY METABOLIC AND BARIATRIC SURGERY

Abstract Disclosure: M.J. Hilaire: None. A. Babcock: None. G. White: None. C. Masson: None. C.A. LeDuc: None. V. Thaker: None. Background and Aims: Metabolic and bariatric surgery (MBS) is known to improve metabolic profile. There is conflicting data on the effects of pre-pregnancy MBS on the offspring growth. We aimed to assess offspring early life growth trajectory born to mothers with MBS before conception compared to those who did not. Methods: Records from pregnancies of women who gave birth at Columbia University Irving Medical Center between January 2020 and March 2023 were collected from the clinical databases and electronic health records. The gestational conditions and offspring early life weight, length and BMI trajectory were compared for: pre-pregnancy BMI < 25, BMI 25-35, BMI > 35 and prior MBS. Mixed effect models were used to compare the longitudinal anthropometric trajectories. Sensitivity analyses was done with propensity matching of the pre-pregnancy MBS group by maternal age, parity, pre-pregnancy BMI and race/ethnicity. Results: Of the 22,111 deliveries with data (51% Hispanic/Latino), 455 (76% Hispanic/Latino) had pre-pregnancy MBS- predominantly sleeve gastrectomy (SG, 57%) or Roux-en-Y Gastric Bypass (RYGB, 41%). Antepartum BMI was 32.5 kg/m2 (SD 6.3) for those with pre-pregnancy MBS with 89.8% pregnancies occurring 1-10 years after surgery. There was a higher proportion of multiparous individuals (42% vs 19-31%) in the MBS group. Pre-pregnancy MBS was associated with lower gestational weight-gain, diabetes, and hypertension compared to those with BMI > 35. For offspring, there was no difference in the birth weight, proportion of SGA was higher (6.6% vs 2.5-2.7%, p < 0.01), LGA was lower (2.0% vs 3.6-5.6%, p < 0.01) and NICU admission rate was comparable (20% vs 15-25%). Offspring anthropometric data till age 36 months was available for approximately 50% of the births. Comparison of longitudinal weight trajectories showed no difference in the offspring between those born after RYGB and BMI < 25 kg/m2 (p =0.8), while those born after SG had persistent rise (p =0.04), adjusting for maternal age, parity, time since surgery and race/ethnicity. In the SG group, boys had higher weight trajectories compared to girls. (p < 0.001). The length trajectories and head circumference at birth were similar across groups. Conclusions: Gestational conditions improved with pre-pregnancy MBS. Pre-pregnancy RYGB, but not SG, was followed by favorable offspring weight trajectory that may have a role in long-term metabolic programming. This study is limited by lack of availability of information on pregnancy glycemic profiles, eating behaviors, dietary patterns, and other social determinants of health. Presentation: 6/3/2024

The Metabolic Programming of Pubertal Onset.

There is increasing evidence that maternal factors such as nutritional status (both under and over-nutrition) and diabetes, alongside prenatal exposure to endocrine disrupting chemicals (EDCs), are associated with early pubertal onset in offspring. Such children are also at increased risk of the metabolic syndrome during adolescence and young adulthood. This literature review focuses on the role of the prenatal environment in programming pubertal onset, and the impact of prenatal metabolic stressors on the declining average age of puberty. A review of all relevant literature was conducted in PubMed by the authors. The mechanism for this appears to be mediated through metabolic signals, such as leptin and insulin, on the kisspeptin-neuronal nitric oxide-gonadotropin releasing hormone (KiNG) axis. Exposed children have an elevated risk of childhood obesity and display a phenotype of hyperinsunlinaemia and hyperleptinaemia. These metabolic changes permit an earlier attainment of the nutritional "threshold" for puberty. Unfortunately, this cycle may be amplified across subsequent generations, however early intervention may help "rescue" progression of this programming.

Key questions and gaps in understanding adipose tissue macrophages and early-life metabolic programming.

The global obesity epidemic, with its associated comorbidities and increased risk of early mortality, underscores the urgent need for enhancing our understanding of the origins of this complex disease. It is increasingly clear that metabolism is programmed early in life and that metabolic programming can have life-long health consequences. As a critical metabolic organ sensitive to early-life stimuli, proper development of adipose tissue (AT) is crucial for life-long energy homeostasis. Early-life nutrients, especially fatty acids (FAs), significantly influence the programming of AT and shape its function and metabolism. Of growing interest are the dynamic responses during pre- and postnatal development to proinflammatory omega-6 (n6) and anti-inflammatory omega-3 (n3) FA exposures in AT. In the US maternal diet, the ratio of "pro-inflammatory" n6- to "anti-inflammatory" n3-FAs has grown dramatically due to the greater prevalence of n6-FAs. Notably, AT macrophages (ATMs) form a significant population within adipose stromal cells, playing not only an instrumental role in AT formation and maintenance but also acting as key mediators of cell-to-cell lipid and cytokine signaling. Despite rapid advances in ATM and immunometabolism fields, research has focused on responses to obesogenic diets and during adulthood. Consequently, there is a significant gap in identifying the mechanisms contributing metabolic health, especially regarding lipid exposures during the establishment of ATM physiology. Our review highlights the current understanding of ATM diversity, their critical role in AT, their potential role in early-life metabolic programming, and the broader implications for metabolism and health.

Integrative omics reveals the metabolic patterns during oocyte growth

Well-controlled metabolism is associated with high quality of oocytes and optimal development of a healthy embryo. However, the metabolic framework that controls mammalian oocyte growth remains unknown. In the present study, we comprehensively depict the temporal metabolic dynamics of mouse oocytes during in vivo growth through the integrated analysis of metabolomics and proteomics. A number of novel metabolic features are discovered during this process. Of note, glycolysis is enhanced and oxidative phosphorylation capacity is reduced in the growing oocytes, presenting a Warburg-like metabolic program. For the nucleotide biosynthesis, the salvage pathway is markedly activated during oocyte growth, whereas the de novo pathway is evidently suppressed. Fatty acid synthesis and channeling into phosphoinositides are specifically elevated in oocytes accompanying primordial follicle activation; nevertheless, fatty acid oxidation is reduced in these oocytes simultaneously. Our data establish the metabolic landscape during in vivo oocyte growth and serve as a broad resource for probing mammalian oocyte metabolism.

Telomere Reprogramming and Cellular Metabolism: Is There a Link?

Telomeres-special DNA-protein structures at the ends of linear eukaryotic chromosomes-define the proliferation potential of cells. Extremely short telomeres promote a DNA damage response and cell death to eliminate cells that may have accumulated mutations after multiple divisions. However, telomere elongation is associated with the increased proliferative potential of specific cell types, such as stem and germ cells. This elongation can be permanent in these cells and is activated temporally during immune response activation and regeneration processes. The activation of telomere lengthening mechanisms is coupled with increased proliferation and the cells' need for energy and building resources. To obtain the necessary nutrients, cells are capable of finely regulating energy production and consumption, switching between catabolic and anabolic processes. In this review, we focused on the interconnection between metabolism programs and telomere lengthening mechanisms during programmed activation of proliferation, such as in germ cell maturation, early embryonic development, neoplastic lesion growth, and immune response activation. It is generally accepted that telomere disturbance influences biological processes and promotes dysfunctionality. Here, we propose that metabolic conditions within proliferating cells should be involved in regulating telomere lengthening mechanisms, and telomere length may serve as a marker of defects in cellular functionality. We propose that it is possible to reprogram metabolism in order to regulate the telomere length and proliferative activity of cells, which may be important for the development of approaches to regeneration, immune response modulation, and cancer therapy. However, further investigations in this area are necessary to improve the understanding and manipulation of the molecular mechanisms involved in the regulation of proliferation, metabolism, and aging.

Brown fat fuels the fire in fever

Fever is a host-pathogen defense mechanism in which the immune system drives a physiologic increase in core body temperature. For over 50 years, it has been known that the temperature of brown adipose tissue (BAT) is increased during the febrile response. However, recent studies suggested that the primary thermogenic protein Uncoupling protein 1 in brown adipocytes does not contribute to fever induction in mice, casting doubt about the functional contribution of BAT to fever. In a new set of studies, Li et al. (2024) provide compelling evidence that fatty acid oxidation is markedly increased in BAT in a Salmonella infection model of fever and strongly suggest that metabolic adaptation in BAT may play a critical role in the febrile response. This article re-opens the debate about how thermogenic and metabolic programs in BAT contribute to fever and raises new questions about whether BAT contributes to host defense against pathogens.

Rap1A Modulates Store-Operated Calcium Entry in the Lung Endothelium: A Novel Mechanism Controlling NFAT-Mediated Vascular Inflammation and Permeability.

Store-operated calcium entry mediated by STIM (stromal interaction molecule)-1-Orai1 is essential in endothelial cell (EC) functions, affecting signaling, NFAT (nuclear factor for activated T cells)-induced transcription, and metabolic programs. While the small GTPase Rap1 isoforms, including the predominant Rap1B, are known for their role in cadherin-mediated adhesion, EC deletion of Rap1A after birth uniquely disrupts lung endothelial barrier function. Here, we elucidate the specific mechanisms by which Rap1A modulates lung vascular integrity and inflammation. The role of EC Rap1A in lung inflammation and permeability was examined using in vitro and in vivo approaches. We explored Ca2+ signaling in human ECs following siRNA-mediated knockdown of Rap1A or Rap1B. Rap1A knockdown, unlike Rap1B, significantly increased store-operated calcium entry in response to a GPCR (G-protein-coupled receptor) agonist, ATP (500 µmol/L), or thapsigargin (250 nmol/L). This enhancement was attenuated by Orai1 channel blockers 10 μmol/L BTP2, 10 μmol/L GSK-7975A, and 5 μmol/L Gd3+. Whole-cell patch clamp measurements revealed enhanced Ca2+ release-activated Ca2+ current density in siRap1A ECs. Rap1A depletion in ECs led to increased NFAT1 nuclear translocation and activity and elevated levels of proinflammatory cytokines (CXCL1, CXCL11, CCL5 [chemokine (C-C motif) ligand 5], and IL-6 [interleukin-6]). Notably, reducing Orai1 expression in siRap1A ECs normalized store-operated calcium entry, NFAT activity, and endothelial hyperpermeability in vitro. EC-specific Rap1A knockout (Rap1AiΔEC) mice displayed an inflammatory lung phenotype with increased lung permeability and inflammation markers, along with higher Orai1 expression. Delivery of siRNA against Orai1 to lung endothelium using lipid nanoparticles effectively normalized Orai1 levels in lung ECs, consequently reducing hyperpermeability and inflammation in Rap1AiΔEC mice. Our findings uncover a novel role of Rap1A in regulating Orai1-mediated Ca2+ entry and expression, crucial for NFAT-mediated transcription and endothelial inflammation. This study distinguishes the unique function of Rap1A from that of the predominant Rap1B isoform and highlights the importance of normalizing Orai1 expression in maintaining lung vascular integrity and modulating endothelial functions.

Migratory lifestyle carries no added overall energy cost in a partial migratory songbird.

Seasonal bird migration may provide energy benefits associated with moving to areas with less physiologically challenging climates or increased food availability, but migratory movements themselves may carry high costs. However, time-dynamic energy profiles of free-living migrants-especially small-bodied songbirds-are challenging to measure. Here we quantify energy output and thermoregulatory costs in partially migratory common blackbirds using implanted heart rate and temperature loggers paired with automated radio telemetry and energetic modelling. Our results show that blackbirds save considerable energy in preparation for migration by decreasing heart rate and body temperature 28 days before departure, potentially dwarfing the energy costs of migratory flights. Yet, in warmer wintering areas, migrants do not appear to decrease total daily energy expenditure despite a substantially reduced cost of thermoregulation. These findings indicate differential metabolic programmes across different wintering strategies despite equivalent overall energy expenditure, suggesting that the maintenance of migration is associated with differences in energy allocation rather than with total energy expenditure.

Crosstalk between FTH1 and PYCR1 dysregulates proline metabolism and mediates cell growth in KRAS-mutant pancreatic cancer cells.

Ferritin, comprising heavy (FTH1) and light (FTL) chains, is the main iron storage protein, and pancreatic cancer patients exhibit elevated serum ferritin levels. Specifically, higher ferritin levels are correlated with poorer pancreatic ductal adenocarcinoma (PDAC) prognosis; however, the underlying mechanism and metabolic programming of ferritin involved in KRAS-mutant PDAC progression remain unclear. Here, we observed a direct correlation between FTH1 expression and cell viability and clonogenicity in KRAS-mutant PDAC cell lines as well as with in vivo tumor growth through the control of proline metabolism. Our investigation highlights the intricate relationship between FTH1 and pyrroline-5-carboxylate reductase 1 (PYCR1), a crucial mitochondrial enzyme facilitating the glutamate-to-proline conversion, underscoring its impact on proline metabolic imbalance in KRAS-mutant PDAC. This regulation is further reversed by miR-5000-3p, whose dysregulation results in the disruption of proline metabolism, thereby accentuating the progression of KRAS-mutant PDAC. Additionally, our study demonstrated that deferasirox, an oral iron chelator, significantly diminishes cell viability and tumor growth in KRAS-mutant PDAC by targeting FTH1-mediated pathways and altering the PYCR1/PRODH expression ratio. These findings underscore the novel role of FTH1 in proline metabolism and its potential as a target for PDAC therapy development.