Ischaemic heart disease shows important differences between men and women, requiring an understanding of sex and gender dissimilarities to improve outcomes. This Scientific Statement provides an updated review of the current knowledge from risk factors to prognosis. It discusses the unequal impact of certain traditional risk factors between men and women, along with additional factors, such as hormonal changes and treatments (including those for transgender people and cancer), pregnancy-related complications, and autoimmune diseases, which contribute to the sex-specific risk profiles. Moreover, it outlines functional and structural sex differences in the pathophysiology (e.g. coronary atheroma plaques and burden, coronary dissection, vasospasm, and microvascular disease) with women being more prone to microvascular disease and endothelial dysfunction, while paradoxically experiencing less severe myocardial ischaemia at similar levels of coronary stenosis. The document further addresses the evaluation of diagnostic tools, which often have a male-centric bias, resulting in underdiagnosis in women who also tend to receive less guideline-recommended treatment. Additionally, women can have different responses and side effects to various preventive and therapeutic treatments, potentially contributing to the worse prognosis documented in acute coronary syndromes with obstructive coronary artery disease, particularly at a young age. Considering all these sex and gender differences and the low enrolment of women in randomized controlled trials, questions arise regarding the optimal treatment for women. Addressing sex differences requires conducting sex-specific research to close the knowledge gap. Overall, the Scientific Statement highlights all relevant sex- and gender-specific dissimilarities to advance clinical practice and identify directions for future research to improve guideline recommendations for equitable care.

Although prompt primary percutaneous coronary intervention (PCI) reduces mortality in patients with ST-elevation myocardial infarction (STEMI), the burden of post-infarction heart failure remains considerable and is expected to increase. A major contributory factor is suboptimal myocardial reperfusion, which persists in up to 60% of cases even with timely revascularization. This is largely driven by microvascular obstruction and ischaemia-reperfusion injury, culminating in the no-reflow phenomenon, a critical prognostic factor associated with impaired infarct healing, adverse left ventricular remodelling, and increased risk of heart failure and death. No-reflow is a complex and heterogeneous phenomenon, identifiable through different invasive and noninvasive technologies. When observed post-PCI, after excluding residual epicardial stenosis, it indicates poor microvascular perfusion and necessitates urgent management. Identifying patients at high risk and implementing early targeted interventions are essential to improving outcomes. Pharmacological therapies, including intracoronary adenosine and nitroprusside, have shown unclear benefit in improving microvascular flow. Non-pharmacological strategies, such as ischaemic postconditioning, intracoronary supersaturated oxygen therapy, stent-retriever thrombectomy, and mechanical left ventricular unloading, have demonstrated promise but require further validation in large-scale clinical trials. This clinical consensus statement summarizes current strategies for the prevention and treatment of no-reflow and underscores the need for improved risk stratification and novel microvasculature-targeted therapies. Addressing this persistent and significant unmet clinical need is crucial for improving care for STEMI patients and for mitigating its long-term complications, including heart failure and mortality.

Recent advances in anti-amyloid therapies for Alzheimer's disease have been promising, but they have also highlighted critical challenges, including increased vascular complications, such as amyloid-related imaging abnormalities. Emerging evidence suggests that the soluble epoxide hydrolase may be a promising therapeutic target due to the involvement of sEH-derived diols in inflammation, oxidative stress, and vascular destabilization. APPPS1 mice, a model of amyloidosis, were crossed with an inducible soluble epoxide hydrolase knock-out mouse line. The knock-out was induced before onset of amyloid deposition, and then the mice were analyzed using histological, molecular, and RNA sequencing techniques. Here, we identify astrocytic soluble epoxide hydrolase as a key mediator of vascular instability in amyloid pathology. Targeted astrocyte-specific deletion of soluble epoxide hydrolase in APPPS1 mice dramatically mitigated vascular changes, reducing the vascular amyloid burden by 67.95% and preserving VE-cadherin architecture. Importantly, vasomotion was markedly impaired in the Alzheimer's disease model and was preserved in soluble epoxide hydrolase-deficient animals. Transcriptomic profiling of vasculature in APPPS1xsEHΔAC mice revealed upregulated expression of genes critical for neurovascular protection. These findings identify soluble epoxide hydrolase as a central regulator of neurovascular dysfunction and underscore its therapeutic potential in increasing vascular stability in amyloidosis-associated diseases, such as Alzheimer's disease.

BACKGROUND AND AIMS:Fulminant myocarditis (FM) is a life-threatening inflammatory cardiomyopathy with high mortality. Soluble ST2 (sST2), traditionally regarded as a decoy receptor for interleukin-33 (IL-33), is markedly elevated in FM, yet its mechanistic and translational roles remain unclear. METHODS:A Coxsackievirus B3-induced FM mouse model was used to define the cellular source and function of sST2 through histological, molecular, and integrated single-cell and single-nucleus transcriptomic analyses. Cardiomyocyte responses were assessed in neonatal murine cardiomyocytes and human engineered heart tissues. The therapeutic efficacy and safety of sST2-neutralizing antibodies were evaluated in vivo, with clinical relevance examined in a cohort of FM patients. RESULTS:sST2 originated predominantly from infiltrating CCR2+ macrophages in FM hearts and aggravated cardiac damage by amplifying inflammation, mitochondrial dysfunction, and contractile failure. Mechanistically, sST2 acted independently of IL-33. It entered cardiomyocytes via IGF2R and bound the transcription factor YY1, preventing its nuclear translocation and repressing mitochondrial electron transport chain gene expression, thereby reducing ATP synthesis. Neutralizing antibodies targeting sST2 effectively restored mitochondrial function, improved hemodynamics, and reduced mortality without evident short-term systemic toxicity. Integrated single-cell and single-nucleus transcriptomic analyses revealed broad therapeutic effects across cardiomyocytes, fibroblasts, endothelial cells, and macrophages. Combined glucocorticoid and anti-sST2 therapy provided additive benefit. Clinically, elevated plasma sST2 independently predicted 30-day mortality or extracorporeal membrane oxygenation requirement in FM patients, outperforming N-terminal pro-B-type natriuretic peptide and cardiac troponin I for prognostic discrimination. CONCLUSIONS:sST2 drives FM by disrupting cardiomyocyte mitochondrial homeostasis independently of IL-33 and represents both a clinically prognostic biomarker and a therapeutic target.

AIMS:A subset of endothelial cells referred to as immunomodulatory endothelial cells (IMEC) has been proposed to regulate T-cell responses in atherosclerosis and after myocardial infarction. Here, we studied the inflammation-induced emergence of IMEC and characterized their crosstalk with T cells. METHODS AND RESULTS:An in vitro model to study IMEC was characterized using flow cytometry and proteomics. Endothelial cell-specific translatome and single-cell transcriptome data from a murine atherogenesis model and single-cell transcriptome data from human atherosclerotic arteries were used to determine pathophysiological relevance. Immunopeptidomics was performed to detect antigen presentation. T-cell chemotaxis, adhesion, and activation were assessed through flow cytometry and microscopy. IMEC were induced by treating human endothelial cells with interleukin-1β, interferon-γ, and transforming growth factor-β2 and expressed lower levels of classical endothelial cell markers and disrupted VE-cadherin expression accompanied by impaired barrier function. IMEC expressed major histocompatibility complex (MHC) class II, proteins involved in antigen processing and presentation (CD83, CD80, and CD86) and pro-inflammatory cytokines as well as chemokines, including CXCL9. An IMEC-like subpopulation was identified in the lumen of carotid arteries in a mouse model of accelerated atherogenesis as well as in human atheromas. Conditioned medium from IMEC enhanced the migration of peripheral blood mononuclear cells and induced T-cell chemotaxis, which was partially inhibited by antagonizing CXCL9. IMEC exhibited a significant down-regulation of proteins related to glycosaminoglycan degradation, consistent with the key role of the glycocalyx in the establishment of chemokine gradients. Indeed, the accumulation of heparan sulphates in IMEC contributed to the adhesion of T cells. Notably, IMEC that had been exposed to monocyte lysates presented 627 peptide antigens on MHC class II and induced T-cell expansion. CONCLUSION:Our data highlight the role of IMEC as non-professional antigen-presenting cells that potentially contribute to T cell-mediated immune responses in cardiovascular disease.

BACKGROUND:Endothelial dysfunction is an early event in atherosclerosis development and is centrally linked with insufficient endothelial NO production. However, chronically increased NO levels, including NO from other cellular sources, may induce endothelial dysfunction. Here, we studied how chronically elevated NO production from erythrocytes, achieved by genetic deletion of ARG1 (arginase-1), impacts smooth muscle cell (SMC) lipid accumulation and atherosclerosis progression. METHODS:Primary aortic SMCs from mice lacking ARG1 in red blood cell (RBC.ARG1-knockout [KO]) were subjected to RNA-sequencing, lipidomic, metabolic, and molecular analyses; atherosclerosis burden was quantified en face and at the aortic root. RESULTS:Increased lipid droplet formation in SMCs from RBC.ARG1-KO mice was observed using brightfield and electron microscopy and confirmed by Oil Red O and boron-dipyrromethene lipid dye staining. RNA sequencing revealed the simultaneous overexpression of genes regulating lipid uptake (Cd36), catabolism (Cpt1a), and de novo lipogenesis (Acaca, Fasn [Fatty acid synthase]) in RBC.ARG1-KO SMCs, and inhibiting fatty acid translocase (CD36), ACC (acetyl-CoA [coenzyme A] carboxylase), or fatty acid synthase prevented the lipid accumulation in RBC.ARG1-KO SMCs. Increased expression of CD36 downstream of NO and overactivated sGC (soluble guanylyl cyclase)-cyclic guanosine monophosphate signaling was identified as a mediator of increased lipid uptake in RBC.ARG1-KO SMCs. Loss of PDE (phosphodiesterase) 2A, coupling cyclic guanosine monophosphate with cyclic adenosine monophosphate and PKA (protein kinase A) activation, was also observed, resulting in AMPK (5' AMP-activated protein kinase) inhibition, thus unlocking acetyl-CoA carboxylase, catalyzing the rate-limiting step in fatty acid synthesis. Inhibiting PDE2A recapitulated the RBC.ARG1-KO SMC phenotype, while inhibiting PKA or ATP generation from cyclic adenosine monophosphate abrogated the lipid droplet accumulation in RBC.ARG1-KO SMCs. Increased Oil Red O-positive aortic atherosclerosis burden in hypercholesterolemic apolipoprotein E-deficient RBC.ARG1-KO mice was confirmed by histology and elevated levels of polyunsaturated long-chain cholesterol esters in aortic atheroma by mass spectrometry lipidomics. CONCLUSIONS:Our findings show the importance of erythrocyte-derived NO for metabolically reprogramming SMCs toward increased fatty acid uptake and lipogenesis, and identify PDE2A as a molecular switch linking chronically activated NO signaling with lipid accumulation and atheroma progression.

Tumor-associated macrophages (TAMs) possess both tumor-promoting and tumor-inhibiting roles. Here, we explore TAMs' anti-tumor functions, focusing on the immune responsive gene 1 (IRG1) and its product, itaconate, in lung cancer development. Spatial metabolomics reveals that endogenous itaconate is markedly depleted within lung tumor regions compared with adjacent non-tumor tissue. Single-cell RNA sequencing shows that macrophages are the primary cells expressing IRG1 in human and mouse lung tumors. Both IRG1 knockout and transplantation of IRG1-depleted bone marrow leads to increased lung tumor growth in various mouse lung tumor models. Additionally, 4-octyl itaconate (Octyl Ita) reduces tumor growth in vitro, in vivo, and in ex vivo human tumor precision-cut lung slices. An integrated multi-omics analysis shows that IRG1/itaconate causes a metabolic shift in cancer cell and pro-tumor macrophages, mainly by inhibiting the pentose phosphate pathway (PPP) through targeting glucose-6-phosphate dehydrogenase (G6PD) activity, thereby suppressing cancer cell growth and transforming pro-tumor macrophages into anti-tumor macrophages. Thus, leveraging IRG1/itaconate's tumor-suppressive effects or using Octyl Ita could be a novel lung cancer therapy.

Spatiotemporal changes in the nuclear lamina and cell metabolism shape cell fate, yet their interplay is poorly understood. Here we identify lamin A/C as a key regulator of cysteine catabolic flux essential for proper cell fate and longevity. Its loss in naive mouse pluripotent stem cells leads to upregulation of the cysteine-generating and catabolizing enzymes, cystathionine γ-lyase (CTH) and cystathionine β-synthase (CBS), thereby promoting de novo cysteine synthesis. Increased cysteine flux into acetyl-CoA fosters histone H3K9 and H3K27 acetylation, triggering a transition from naive to primed pluripotency and abnormal cell fate and function. Conversely, the toxic gain-of-function mutation of Lmna, encoding lamin A/C and associated with premature ageing, reduces CTH and CBS levels. This reroutes cysteine catabolic flux and alters the balance between H3K9 acetylation and methylation, crucially impacting germ layer formation and genome stability. Notably, modulation of Cth and Cbs rescues the abnormal cell fate and function, restores the DNA damage repair capacity and alleviates the senescent phenotype caused by lamin A/C mutations, highlighting the potential of modulating cell metabolism to mitigate epigenetic diseases. Lamin A/C in the nuclear lamina is identified as a regulator of cysteine catabolic flux, necessary for cell fate decisions and function.

Aims:Angiotensin II (AngII) causes hypertension and vascular inflammation and is essential in neurohumoral activation promoting the development of heart failure. The role of the adaptor protein myeloid factor of differentiation 88 (MyD88) driving this pathology remains incompletely understood. Methods and results:Male C57BL/6JMyD88-/-, LysMCre/wtMyD88LSL/LSL, LysMCre/wt, TLR2-/-, TLR4-/-, TLR7-/-, and TLR9-/- mice were investigated (1 mg/AngIIkg/d for 7 days). Additionally, we performed biodata analyses from a population-based cohort study and human protein network interactome analyses to understand the role of MyD88 in hypertension. MyD88 deficiency attenuated AngII-induced hypertension and endothelial dysfunction in conductance and resistance vessels, surpassing the effect of single TLR deficiencies. Vascular mRNA expression levels of vcam-1, nos2, nox2, cd62L, cd68, ccl2, il12, and il1b and accumulation of CD11b+Ly6Chi inflammatory monocytes and interferon-g+ NK cells were significantly dampened in MyD88-/-. Vascular protection was conferred by MyD88 deficiency in bone marrow-derived cells. Re-expression of MyD88 in LysMCre/wtMyD88LSL/LSL mice restored AngII-induced pathology, revealing that myeloid cells drive vascular dysfunction in a MyD88-dependent manner. Computational analyses of the human protein interactome demonstrated that MyD88 expression significantly associates with proteins encoded by genetic loci associated with blood pressure traits in multiple GWAS. In hypertensive individuals of the Gutenberg Health Study, monocytic MyD88 mRNA expression was associated with prevalent heart failure and all-cause mortality after a median follow-up of 16.5 years. Conclusion:MyD88 promotes AngII-induced vascular dysfunction and arterial hypertension and might serve as both an inflammatory diagnostic marker and a drug target to tackle the risk of death and incident heart failure in hypertensive patients.

Abstract Background Endothelial cells express numerous microproteins (miPs) encoded by small open reading frames (smORFs), yet the biological function of most remains unknown. This study set out to characterize a novel 69 amino acid miP encoded within the FERM domain containing kindlin-3 transcript (miP-FERMT3), which is upregulated under inflammatory conditions. Methods Confocal microscopy was used to determine miP-FERMT3 localization, and its interaction partners were determined by mass spectrometry and immunoblotting. RNA sequencing and quantitative mass spectrometry were performed to assess transcriptional and proteomic alterations. Cell proliferation and cell cycle progression were examined by live cell imaging, EdU incorporation and flow cytometry, while senescence was determined by β-galactosidase staining, live cell imaging and RT-qPCR-based analysis of telomere length. Results In endothelial cells, miP-FERMT3 localized mainly to centriole subdistal appendages, where it colocalized with ninein and CEP170 and induced centrosome amplification. The expression of miP-FERMT3 caused cell cycle arrest and DNA damage, evidenced by γ-H2AX foci and nuclear p53 accumulation. Consistent with this, miP-FERMT3-expressing endothelial cells exhibited downregulation of genes required for cell-cycle progression and upregulation of genes involved in cell cycle inhibition and senescence. However, canonical p53 target genes were not induced and cell cycle arrest occurred independently of p53. Mechanistically, miP-FERMT3 interacted with proteins involved in ubiquitin/proteasome-dependent protein catabolism, including PSMD9, CUL2 and TRIM8, and its expression increased protein ubiquitination, centrosomal neddylation and proteasomal activity. Notably, enhanced proteasomal turnover of p21 in miP-FERMT3-expressing endothelial cells resulted in replication stress, as evidenced by increased CHK1 phosphorylation. These alterations culminated in rapid induction of cellular senescence, characterized by enlarged cell size, β-galactosidase activity, telomere shortening and a paracrine pro-inflammatory activation of naïve endothelial cells. Analyses of independent murine and human transcriptomic and proteomic aging datasets further revealed that FERMT3 expression and protein abundance increase with age. Conclusions miP-FERMT3 is a novel regulator of protein catabolism that promotes p21 degradation, replication stress and p53-independent cell cycle arrest and senescence in endothelial cells. Given the aging-associated upregulation of FERMT3 in mouse and human endothelial cells, increased miP-FERMT3 expression may contribute to the onset of vascular senescence as a hallmark of aging.

Immunotherapy with immune checkpoint blockade (ICB) in epithelial ovarian carcinoma (EOC) shows limited clinical benefit only for a small subset of patients. Overall response rates are low, so that overcoming immunotherapy resistance and improved stratification are key. In this study, we investigated the immunometabolic landscape of EOC with a focus on omental metastases, identifying lipid-laden macrophages as central elements for actionable therapeutic vulnerabilities and giving rise to biomarkers for improved patient stratification. Using patient-derived explants, we demonstrated a functional dichotomy inside the typically lipid-rich microenvironment of omental metastases: augmented maintenance of effector T cell function, while lipid uptake and processing by tumor-associated macrophages (TAMs) induces oxidative stress-dependent signaling programs, which drive macrophage dysfunction and immune suppression. Pharmacological modulation of lipid-driven signaling pathways through CCR5 inhibition (inflammation modulation through maraviroc) or blockade of the lipid scavenger receptor CD36 reprograms TAMs, restores T cell activity, and enhances antitumor immune responses within lipid-rich tumor niches. Mechanistically, studies in humanized mouse models reveal that maraviroc-mediated CCR5 inhibition induces transcriptional programs associated with immune activation in stressed, lipid-laden human TAMs. Consistent with these mechanistic insights, we demonstrated that the specific immunometabolic niche in omental metastases is clinically associated with responsiveness to ICB. We propose a non-invasive radiomics and machine-learning-based analysis of imaging data to assess omental involvement for patient stratification.

AIMS:Microproteins (miPs) translated from small open reading frames (smORFs) are crucial regulators of cell function. However, the expression and function of miPs in endothelial cells and alterations in miP expression linked with inflammation and cardiovascular disease, remain largely unexplored. METHODS AND RESULTS:An optimized proteogenomic approach combining RiboTag RNA-sequencing and mass spectrometry of the small molecular mass proteome was utilized to identify endothelial cell-specific miPs. Heart, lung, and blood vessels from endothelial cell-specific RiboTag mice and human endothelial cells were studied under homeostatic and inflammatory conditions. We identified 2739 murine as well as 1365 intracellular and 607 extracellular human endothelial cell miPs encoded from previously non-canonical (unannotated) smORFs. Vascular inflammation induced in vitro by interleukin-1β (IL-1β) and in vivo through PCSK9 overexpression, high-fat diet, and partial carotid artery ligation significantly altered smORF expression. An additional 347 miPs were detected in human serum, 23 decreasing and 31 increasing, after cardiac damage. The expression of an inflammation-induced miP encoded by an internal smORF within the proline-serine-threonine phosphatase interacting protein 2 (PSTPIP2) transcript, that is, miP-PSTPIP2, was assessed using a custom antibody. miP-PSTPIP2 expression was upregulated in IL-1β-treated human endothelial cells, in pre-atherosclerotic murine carotid arteries and detected in carotid arteries from patients with atherosclerosis. The relevance of 250 miPs for endothelial cell growth and viability was demonstrated using a high-throughput clustered regularly interspaced Short palindromic Repeats (CRISPR)/Cas9 screen. CONCLUSION:Taken together, we document the existence of a large number of human and murine miPs encoded by non-canonical smORFs and their altered expression in inflammatory conditions. The identification of secreted miPs suggests that they may also exert autocrine or paracrine functions. These novel small peptides modulate cell proliferation and survival in endothelial cells and may play a significant role in human cardiovascular disease.

Recent advances in anti-amyloid therapies for Alzheimer's disease have been promising, but they have also highlighted critical challenges, including increased vascular complications, such as amyloid-related imaging abnormalities. Emerging evidence suggests that the soluble epoxide hydrolase may be a promising therapeutic target due to the involvement of sEH-derived diols in inflammation, oxidative stress, and vascular destabilization. APPPS1 mice were crossed with an inducible soluble epoxide hydrolase knock-out mouse line. The knock-out was induced before onset of amyloid deposition, and then the mice were analyzed using histological, molecular, and RNA sequencing techniques. Here, we identify astrocytic soluble epoxide hydrolase as a key mediator of vascular instability in Alzheimer's disease. Targeted astrocyte-specific deletion of soluble epoxide hydrolase in APPPS1 mice dramatically mitigated vascular changes, reducing the vascular amyloid burden by 67.95% and preserving VE-cadherin architecture. Importantly, vasomotion was markedly impaired in the Alzheimer's disease model and was preserved in soluble epoxide hydrolase-deficient animals. Transcriptomic profiling of vasculature in APPPS1xsEHΔAC mice revealed upregulated expression of genes critical for neurovascular protection. These findings identify soluble epoxide hydrolase as a central regulator of neurovascular dysfunction and underscore its therapeutic potential in increasing vascular stability in Alzheimer's disease. ### Competing Interest Statement The authors have declared no competing interest. Deutsche Forschungsgemeinschaft, 4b03813475, 419157387 Emmy Noether Award, HE 6867/3-1 SFB 1531, 456687919 Alzheimer's Association, AARF-17-529810 Alzheimer Forschung Initiative, 20041 BMBF, FK:01EW2308A Neuron-ERANET Cardio-Pulmonary Institute EXC 2026, 390649896 CRC1080, 221828878 Josef Buchmann PhD Starter Scholarship

Endothelial-to-mesenchymal transition (EndMT) is a crucial, dual-phase process in cardiac repair after myocardial infarction (MI), driving both initial scar stabilization and subsequent pathological fibrosis. Therapeutic targeting requires precise temporal control rather than complete inhibition. This study identifies the matricellular protein SPARC-related modular calcium-binding protein 1 (SMOC1) as a novel regulator of EndMT. Analysis of single-cell RNA sequencing data from post-MI mouse hearts revealed that SMOC1 is highly enriched in a subpopulation of endothelial cells undergoing late EndMT. In vitro, SMOC1 expression was upregulated during cytokine-induced EndMT in human endothelial cells. Its siRNA-mediated knockdown exacerbated the EndMT phenotype, increasing mesenchymal marker expression and cell morphology changes, effects rescued by recombinant SMOC1 (rSMOC1). Mechanistically, SMOC1 deficiency enhanced TGF-β2-induced SMAD2 phosphorylation, while rSMOC1 attenuated this pathway and promoted a shift from the short to the long, signaling-competent isoform of endoglin. In vivo, endothelial-specific SMOC1 deficiency (SMOC1 ΔEC ) in mice promoted age-associated EndMT and profoundly worsened post-MI outcomes. After MI, SMOC1 ΔEC mice exhibited exacerbated cardiac dysfunction, ventricular dilation, pathological fibrosis, increased inflammatory cell infiltration, reduced survival, and a higher incidence of cardiac rupture compared to controls. Collectively, these findings establish SMOC1 as a critical endogenous modulator of EndMT that restrains its pathological progression. SMOC1 coordinates endothelial cell phenotype, in part by fine-tuning TGF-β/endoglin signaling, and its loss accelerates maladaptive remodeling post-MI. Thus, SMOC1 represents a potential therapeutic target for spatially and temporally controlling EndMT to improve cardiac repair

Oxidative stress is a major driver of cardiovascular disease; however, the fast changes in cellular metabolism caused by short-lived reactive oxygen species (ROS) remain ill-defined. Here, we characterized changes in the endothelial cell metabolome in response to acute oxidative challenges and identified novel redox-sensitive metabolic enzymes. H2O2 selectively increased the amount of α-ketoglutaramate (αKGM), a largely uncharacterized metabolite produced by glutamine transamination and an unrecognized intermediate of endothelial glutamine catabolism. In addition, H2O2 impaired the catalytic activity of nitrilase-like 2 ω-amidase (NIT2), the enzyme that converts αKGM to α-ketoglutarate (αKG), by the reversible oxidation of specific cysteine residues. Moreover, a NIT2 gene variant exhibited decreased expression in humans and was associated with increased plasma αKGM concentration. Endothelial-specific knockout of NIT2 in mice increased cellular αKGM levels and impaired angiogenesis. Further, NIT2 depletion impaired endothelial cell proliferation, sprouting, and induced senescence. In conclusion, we uncover NIT2 as a redox-sensitive enzyme of the glutamine transaminase-ω-amidase pathway that acts as a metabolic switch modulating endothelial glutamine metabolism in mice and humans.

Background Human endothelial cells express numerous microproteins (miPs) encoded by small open reading frames (smORFs) distributed throughout the genome, yet the biological functions of most remain unknown. This study set out to characterize a novel 69 amino acid miP encoded by a smORF located within the coding sequence of the FERM domain containing kindlin-3 transcript (miP-FERMT3). Methods Confocal microscopy was used to determine the subcellular localization of miP-FERMT3 in endothelial cells and its interaction partners were determined by mass spectrometry and immunoblotting. RNA sequencing identified transcriptional alterations induced by miP-FERMT3 overexpression. Cell proliferation and cell cycle stages were assessed by live cell imaging, EdU incorporation and flow cytometry, while senescence was examined by senescence-associated β-galactosidase staining, live cell imaging and RT-qPCR-based measurement of telomere length. Results In endothelial cells miP-FERMT3 localized mainly to centriole subdistal appendages, where it interacted with proteins involved in ubiquitin- and proteasome-dependent protein catabolism, including PSMD9, CUL2 and TRIM8. Consistent with these interactions, cells expressing miP-FERMT3 exhibited increased global protein ubiquitination, enhanced centrosomal neddylation and elevated proteasomal activity. MiP-FERMT3 also promoted the nuclear accumulation of p53, which subsequently repressed FOXM1 expression, leading to the downregulation of genes required for cell-cycle progression and upregulation of genes involved in cell cycle inhibition, resulting in cell-cycle arrest. Cells expressing the miP also demonstrated multiple hallmarks of cellular senescence, including enlarged size, DNA damage, increased senescence-associated β-galactosidase activity, telomere shortening and paracrine pro-inflammatory activation of naïve endothelial cells. Analyses of independent murine and human transcriptomic and proteomic aging datasets further revealed that FERMT3 expression and protein abundance increase with age. Conclusions These findings identify miP-FERMT3 as a novel regulator of protein catabolism and p53-dependent cell cycle arrest and cellular senescence in endothelial cells. Given the aging-associated upregulation of FERMT3 in mouse and human endothelial cells, increased miP-FERMT3 expression may contribute to the onset of vascular senescence as a hallmark of aging. ### Competing Interest Statement The authors have declared no competing interest. German Research Foundation, SFB1531/1, 456687919 German Research Foundation, Excellence Cluster Cardio-Pulmonary Institute, EXC 2026, 390649896

Whether, when, and how lymphatic vessels undergo cell death remains poorly understood. Here we identify ferroptosis as a physiological, cell-intrinsic regulator of the lymphatic endothelial cell survival during development and following injury, in stark contrast to the resilient organotypic blood endothelial cells. The lymphatic susceptibility to ferroptosis stems from tampered cystine/ hydropersulfide metabolism, alongside reduced glutathione availability triggered by an SH3RF3 E3 ligase mediated GPX4 degradation, and enhanced integration of polyunsaturated fatty acid enriched membrane phospholipids. Inducing ferroptosis genetically or pharmacologically elevated lymphatic lipid peroxidation, halted embryonic lymphangiogenesis and prevented post-injury lymphatic overgrowth while simultaneously shaped immune responses. Conversely, ferroptosis inhibition through saturated fatty acid supplementation led to pathological lymphatic hyperplasia. Targeting lymphatic ferroptotic mechanisms holds promise against pathological lymphatic growth in response to injury. ### Competing Interest Statement The authors have declared no competing interest.

The bifunctional soluble epoxide hydrolase (sEH) represents a promising target for inflammation-related diseases. Although potent inhibitors targeting each domain are available, sEH-PROTACs offer the unique ability to simultaneously block both enzymatic functions, mimicking the sEH knockout phenotype, which has been associated with reducing inflammation, including neuroinflammation, and delaying the progression of Alzheimer's disease. Herein, we report the structure-based development of a potent sEH-PROTAC as a useful pharmacological tool. In order to facilitate a rapid testing of the PROTACs, a cell-based sEH degradation assay was developed utilizing HiBiT technology. We designed and synthesized 24 PROTACs. Furthermore, cocrystallization of sEH with two selected PROTACs allowed us to explore the binding mode and rationalize the most optimal linker length. After comprehensive biological and physicochemical characterization of this series, the most optimal PROTAC 23 was identified in primary human and murine cells, highlighting the potential of using 23 in disease-relevant cell and tissue models.