BACKGROUND: Sodium-glucose co-transporter 2 inhibitors (SGLT2i), when combined with metformin (COMBI), offer multi-organ protective effects in patients with type 2 diabetes (T2D), particularly those at high risk of cardiovascular or renal complications. However, the underlying molecular mechanisms remain poorly understood. METHODS: We profiled 303 targeted serum metabolites in 1494 participants of the KORA study, including T2D patients treated with COMBI therapy, metformin monotherapy, or no glucose-lowering medication. Additionally, metabolomic profiling was quantified on seven tissues (plasma, liver, adrenal glands, adipose tissue, testis, lung, and cerebellum), and related hepatic transcripts were evaluated in 40 mice. Multivariable linear regression analyses, adjusted for age, sex, BMI, lifestyle, glycemic, and cardiovascular risk factors, were applied to human data; tissue-specific regression analyses were conducted for murine samples. Identified metabolites were further investigated using biochemical pathway analyses and literature review. RESULTS: COMBI therapy was associated with significant changes in metabolite profiles. In humans, 10 metabolites were significantly altered compared to metformin monotherapy. In mice, 82 altered metabolites were identified in plasma, 52 in liver, 30 in adrenal glands, 12 in adipose tissue, seven in testis, seven in lung, and six in cerebellum. COMBI therapy lowered threonine concentrations in both human serum and murine plasma but raised threonine, glycine, and urea cycle metabolites (citrulline, asymmetric dimethyl arginine (ADMA), and ornithine) in murine liver. This was accompanied by enhanced hepatic expression of Slc38a2, a threonine transporter gene. In humans, urea cycle metabolites correlated strongly with the fibrosis-4 index, a marker of liver fibrosis. Additionally, COMBI therapy elevated ketone body markers, such as hydroxybutyrylcarnitine, across murine liver, plasma, adrenal glands, adipose tissue, and testis. CONCLUSIONS: COMBI therapy modulates amino acid metabolism, the urea cycle, and ketone body production, suggesting potential mechanisms underlying its protective effects against liver fibrosis and male subfertility. These findings provide novel insights into the systemic metabolic actions of COMBI therapy and highlight its translational potential to improve clinical outcomes in T2D patients.

The prevalence of metabolic diseases, including obesity and type 2 diabetes, continues to rise. Although GLP-1 receptor agonists (GLP-1RAs) now provide the first effective treatment options for patients with obesity, many still fail to reach their target weight. Interleukin (IL)-22 has emerged as a promising therapeutic due to its ability to modulate key metabolic factors. This study evaluated the potential of a novel long-acting lipidated IL-22 analogue as a complementary treatment to GLP-1RAs in mouse models. Lipidated IL-22 induced up to 20% weight reduction as a monotherapy and up to 40% in combination with GLP-1RAs, demonstrating additive efficacy. Lipidated IL-22 preserved lean body mass with less than half the lean mass loss of GLP-1RAs or caloric restriction. Glycemic control was also enhanced, with lipidated IL-22 normalizing blood glucose, and improving insulin sensitivity independent of food intake. Mechanistically, lipidated IL-22 enhanced intestinal secretion of anorectic factors like PYY and doubled fecal energy loss through reduced intestinal calorie absorption. These findings demonstrate the novel intestinal mechanisms of action of lipidated IL-22 and its additive potential to GLP-1RA treatment. Therefore, lipidated IL-22 is strongly positioned as a novel anti-obesity treatment that can address critical unmet needs in the treatment of metabolic diseases.

The FAIR principles guide data stewardship towards maximizing the value of scientific data while offering a high level of flexibility to accommodate differences in standards and scientific practices. Research communities have developed and implemented domain-specific workflows to make their data FAIR. This work compares the implementation of two externally developed structured FAIRification workflows-a generic workflow and a domain-specific workflow- using the example of metadata captured in diabetes research in Germany and applying the FAIR data maturity model developed by the Research Data Alliance. Interestingly, the implementation of both workflows required similar resources and led us to achieve the same FAIRness rating. We therefore conclude that the adaptations made in the FAIRification workflow for health research data improve efficiency but do not necessarily lead to higher FAIRness scores when applied to core data sets. Based on the results of our workflow comparison, we identified a list of requirements that should be met for the FAIRification of a core data set regardless of the workflow employed. In the future, FAIR data strategies and infrastructure should be planned and implemented as early as possible in the FAIRification journey. It is anticipated that this comparative analysis will help establish standard operating procedures for the FAIRification of core data sets for health studies.

In recent decades, obesity and diabetes have reached pandemic levels, with obesity now recognised as a major health risk factor. Evidence shows that metabolic diseases are more pronounced in the offspring of malnourished parents, suggesting that predisposition can be inherited via epigenetic information in gametes. This has sparked growing interest in small regulatory RNAs in sperm as carriers of epigenetic inheritance. However, the functional annotation of dysregulated sperm microRNAs (miRNAs) in obesity and diabetes remains limited. This work addresses this gap by analysing publicly available datasets of diet-regulated sperm miRNAs and linking them to genes functionally associated with obesity and diabetes. We systematically identified diet-responsive sperm miRNAs and overlapped their predicted targets with genes associated with metabolic phenotypes, as catalogued by the International Mouse Phenotyping Consortium (IMPC). First, in a sequence-based approach, we uncovered 11,272 and 6528 potential target genes for miRNAs regulated by the acute and chronic HFD interventions, respectively. Second, by overlapping these predicted target genes of sperm miRNAs with our IMPC-derived list of 889 genes associated with obesity and diabetes, we identified 805 acute- and 546 chronic-HFD predicted response genes. This approach thus associates function with regulated miRNAs and revealed distinct miRNA-gene networks in acute versus chronic HFD models, including shared nodes in pathways related to insulin signalling, lipid metabolism, and β-cell function. To support further research, we provide the field with the ShinyFatSperm App (https://reproproteomics.shinyapps.io/ShinyFatSperm/), which facilitates the functional interpretation of diet-regulated sperm miRNAs and enables users to explore their roles in the intergenerational transmission of metabolic disease risk. Taken together, our findings reinforce the concept that paternal dietary exposures can influence offspring health through epididymal- and sperm-borne miRNAs, and related epigenetic mechanisms. This work provides a roadmap for hypothesis-driven investigation into the intergenerational inheritance of metabolic diseases and highlights the urgent need for translational strategies to interrupt this cycle.

Lay summary The aim of this study is to highlight potential differences between embryos conceived naturally and those conceived via in vitro fertilisation (IVF). While the current scientific literature generally assumes that differences between these two modes of conception exist, many studies do not provide detailed phenotypic data, e.g. bodyweight, blood glucose and other observational metabolic health parameters. In addition, comparisons are often complicated by variations in choosing different strains of foster mothers to carry embryos. By addressing these limitations, our short summary and overview provide a well-defined comparison within a controlled experimental setup including a high-fat diet feeding period as metabolic challenge. We make the resulting data publicly available to offer a reference point for researchers using a specific mouse strain as fosters and to improve transparency regarding the specific differences in metabolic health observed between natural conception and IVF in this context.

Ferroptosis, driven by uncontrolled peroxidation of membrane phospholipids, is distinct from other cell death modalities because it lacks an initiating signal and is surveilled by endogenous antioxidant defenses. Glutathione peroxidase 4 (GPX4) is the guardian of ferroptosis, although its membrane-protective function remains poorly understood. Here, structural and functional analyses of a missense mutation in GPX4 (p.R152H), which causes early-onset neurodegeneration, revealed that this variant disrupts membrane anchoring without considerably impairing its catalytic activity. Spatiotemporal Gpx4 deletion or neuron-specific GPX4R152H expression in mice induced degeneration of cortical and cerebellar neurons, accompanied by progressive neuroinflammation. Patient induced pluripotent stem cell (iPSC)-derived cortical neurons and forebrain organoids displayed increased ferroptotic vulnerability, mirroring key pathological features, and were sensitive to ferroptosis inhibition. Neuroproteomics revealed Alzheimer's-like signatures in affected brains. These findings highlight the necessity of proper GPX4 membrane anchoring, establish ferroptosis as a key driver of neurodegeneration, and provide the rationale for targeting ferroptosis as a therapeutic strategy in neurodegenerative disease.

PURPOSE: The purpose of this project was to identify novel Usher syndrome (USH) candidate genes from phenotyping data of 9,139 knockout (KO) mouse lines. METHODS: We evaluated phenotype data for concurrent retinopathy and hearing abnormalities in single-gene KO mice generated by the International Mouse Phenotyping Consortium (IMPC). A search was performed to determine if each gene had been previously established in retinopathy and/or deafness in humans. Bioinformatic tools were used to predict protein interactions, molecular functions, signaling pathways, and expression of human orthologs of candidate genes in retina and inner ear. RESULTS: We identified 18 single-gene KO lines exhibiting hearing abnormality and retinopathy after ear and eye examination, respectively, and/or by histopathology. The molecular functions and signaling pathways of the human orthologues of 18 candidate genes partially overlapped with USH genes. Particularly, FER and DYRK1B proteins were predicted to interact with proteins encoded by known ciliopathy genes. ADIPOR1, ATP8B1 and MPDZ were associated with retinal degeneration in humans. CHSY1 and IDUA may be a pathogenic cause of hearing impairment in people. Additionally, CHSY1, CSTB and SPRED1 were located adjacent to unsolved genetic loci related to USH. CONCLUSIONS: A screen of 9,139 KO mouse lines revealed 18 candidate genes exhibiting both retinal and inner ear abnormality consistent with principle clinical features associated with USH. As the observed phenotypes are attributed to gene deletion in mice, these genes warrant further study to determine causation of retinal degeneration and hearing loss in patients.

Heart weight (HW) is a critical parameter in cardiology and mouse research, commonly normalized to body weight (BW) or tibia length (TL) to account for size differences. Ratio-based normalization, however, assumes strict proportionality between variables, an assumption that is rarely tested and may bias group comparisons. We analysed HW, BW, and TL measurements from over 25,000 C57BL/6N wildtype mice generated by the International Mouse Phenotyping Consortium. Sex- and age-stratified analyses were combined with simulation-based modelling to evaluate empirical scaling relationships and the statistical behaviour of ratio-based normalization. Across all age and sex groups, correlations between HW, BW, and TL were negligible to weak, indicating substantial deviations from proportionality. Simulations demonstrated that ratio-based normalization can generate misleading results, including spurious or reversed group differences, when proportionality assumptions are violated. Ratios were consistent with linear and allometric models only under strictly proportional conditions, characterized by regression lines passing through the origin. Linear models with covariate adjustment and allometric scaling provide more robust and biologically meaningful frameworks for organ weight analysis. Ratio-based normalization should be avoided unless key mathematical assumptions are met.

[This corrects the article DOI: 10.3389/fcvm.2025.1695034.].

Hypertrophic cardiomyopathy (HCM) is driven by sarcomeric mutations that cause energetic failure and secondary inflammation. This study demonstrates that targeting this metabolic-inflammatory axis with pioglitazone or its peroxisome proliferator-activated receptor gamma inactive enantiomer, R-pioglitazone, reverses disease progression in a murine HCM model. Both agents restored mitochondrial function (including Mitochondrial Pyruvate Carrier 1 [MPC1] levels) and resolved inflammation. Notably, R-pioglitazone showed superior efficacy, reducing interstitial fibrosis by >95% and hypertrophy by 33% without affecting healthy control hearts. These findings identify R-pioglitazone as a promising, mechanism-based candidate for disease-modifying therapy in HCM.

Glutaric aciduria type 1 is caused by inherited deficiency of glutaryl-CoA dehydrogenase and subsequent accumulation of neurotoxic metabolites. Clinically, the disease is characterized by striatal damage and dystonic movement disorder in untreated infants. Despite newborn screening and pre-symptomatic therapy start, about one-third of patients still develop neurological symptoms. Furthermore, progressive white matter changes and chronic kidney disease highlights the need for improved therapies. To elucidate the potential of substrate reduction therapy for GA1 we investigated whether aminoadipate-semialdehyde synthetase, the first enzyme of the lysine oxidation pathway, could serve as therapeutic target. Therefore, we studied whether Gcdh knockout (KO) mice, a known animal model for GA1, were rescued by additional knockout of Aass. Gcdh/Aass KO mice were clinically indistinguishable from wild-type mice and showed a marked reduction of glutaric acid in brain (20.9 µg/mg protein vs. 59.2 µg/mg protein; p = 0.001), liver (23.5 µg/mg protein vs. 104.8 µg/mg protein; p = 0.001), and urine (11.9 mol/mol creatinine vs. 166.5 mol/mol creatinine; p = 0.001). The effect was less pronounced for 3-hydroxyglutaric acid. Unlike Gcdh KO mice, Gcdh/Aass KO mice did not develop a severe phenotype under high-lysine diet. In conclusion, knockout of Aass partially rescues the severe phenotype of Gcdh KO mice, providing a potential therapeutic target.

Down syndrome (DS) is the most prevalent form of intellectual disability (ID) globally, with an incidence rate of approximately 1 in 1000 births, affecting over 5 million individuals worldwide. DS is characterized by a genetic profile that predisposes individuals to a range of medical and cognitive conditions, including ID and obesity, which place considerable demands on healthcare systems and families alike. Mouse models carrying DS-related genetic mutations offer valuable tools for investigating the pathophysiological mechanisms underlying DS-associated behavioral and metabolic alterations. These models also allow for an evaluation of the impact of both intrinsic and extrinsic environmental factors, aiding in the development of biomarkers and personalized therapies for individuals with DS. In this article, we establish a detailed and comprehensive phenotyping pipeline designed to incorporate high-resolution assessments of cognitive, metabolic, and behavioral variables. Using advanced phenotyping techniques alongside standardized protocols in DS mouse models, this approach systematically captures the variability of DS-associated traits. Our phenotyping pipeline aims to cover the pathways leading to cognitive dysfunction and metabolic imbalances in DS, paving the way for targeted intervention strategies. © 2026 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Diet challenge (chow diet vs. high-fat diet). Basic Protocol 2: Fecal or saliva microbiota analysis. Basic Protocol 3: Body composition assessment by quantitative nuclear magnetic resonance. Basic Protocol 4: Indirect calorimetry. Basic Protocol 5: Blood collection and processing. Basic Protocol 6: Oral glucose tolerance test. Basic Protocol 7: Long-term monitoring of social groups. Alternate Protocol 1: Analysis of short-term dyadic interactions between unfamiliar mice of the same genotype. Alternate Protocol 2: Analysis of short-term dyadic interactions of mice from the tested strain with an unfamiliar C57BL/6J mouse. Basic Protocol 8: Intraperitoneal insulin sensitivity test. Basic Protocol 9: Y-maze spontaneous alternation test. Alternate Protocol 3: Y-maze spontaneous alternation test version 2. Basic Protocol 10: Marble-burying analysis. Alternate Protocol 4: Marble-burying analysis version 2. Basic Protocol 11: Object location memory/novel object recognition. Alternate Protocol 5: Novel object recognition in the Y-maze apparatus. Basic Protocol 12: Nest-building test. Basic Protocol 13: Sucrose preference analysis. Basic Protocol 14: Histopathology © 2026 by John Wiley & Sons, Inc.

BACKGROUND & AIMS: Obesity and type 2 diabetes are global health challenges driven by genetic and environmental factors, including diet. While intermittent fasting improves metabolic health, the hepatic mechanisms linking feeding transitions to systemic metabolic regulation remain unclear. We investigated whether Indian Hedgehog (Ihh), a liver-derived hepatokine, coordinates metabolic responses to nutritional transitions. METHODS: We employed genetic and epigenetic tools, including liver-specific deletion of the PRC2 component Eed, to study Ihh regulation. In vivo metabolic phenotyping, thermogenic gene profiling, and Ihh immunoneutralization assessed its function. VLDL-associated Ihh levels were measured and their correlations with metabolic traits were analyzed in humans. RESULTS: Ihh is induced upon feeding and promotes adipose thermogenesis, enhancing metabolic flexibility. The Ihh locus in hepatocytes resides in a bivalent chromatin state; hepatic Eed deletion derepresses Ihh, conferring resistance to diet-induced obesity and insulin resistance. Immunoneutralization of Ihh reverses this protection, confirming its necessity. Ihh circulates in complex with VLDL. Human Ihh-VLDL levels decline with age and correlate with improved metabolic parameters, including insulin sensitivity, HDL/LDL ratio, and reduced adiposity. CONCLUSIONS & IMPLICATIONS: Ihh is a liver-derived, epigenetically regulated hepatokine that links nutrient timing to systemic metabolic control by stimulating thermogenesis and promoting glucose homeostasis. These findings identify Ihh as a key inter-organ signal coupling hepatic chromatin dynamics to energy balance. The age-related decline in circulating Ihh and its strong association with metabolic health suggest that enhancing Ihh signaling may represent a novel therapeutic avenue for obesity and type 2 diabetes.

The epididymis is a highly specialised organ essential for promoting the post-testicular functional maturation of spermatozoa, a process underpinning male fertility. This review examines the latest proteomics advances that have been used to unravel the complex molecular landscape of the epididymis, revealing the dynamic protein networks that shape sperm function beyond their genomic and transcriptomic blueprints. Here, we highlight how high-resolution mass spectrometry has helped to map the proteomic signatures of epididymal tissue, luminal extracellular vesicles (epididymosomes), and spermatozoa at different maturation stages, pinpointing key regulators of motility, capacitation, fertilisation competence, and immune regulation. However, critical knowledge gaps remain, including deep protein characterisation of the cytoplasmic droplet, epididymal fluid, and relatively underexplored anatomical tissue segments such as the corpus and cauda epididymis. We discuss how integrating global proteomic insights with complementary omics, single cell proteomics and advanced imaging is poised to reveal the spatial and temporal refinement of the sperm proteome, providing insights into how its disruption may contribute to idiopathic infertility. To promote data accessibility and accelerate discovery in epididymal biology, we introduce ShinyEpididymis (https://reproproteomics.shinyapps.io/ShinyEpididymis/), an interactive, web-based resource integrating publicly available proteomic datasets from spermatozoa, epididymosomes, and epididymal tissue. This platform enables researchers to rapidly query proteins of interest, explore spatial patterns of expression, and identify potential biomarkers or therapeutic targets. By consolidating current knowledge and defining future priorities, this review positions proteomics at the forefront of understanding epididymal biology, emphasising its clinical relevance and untapped potential for diagnosing and treating male infertility.

Understanding the complex factors influencing mammalian metabolism and body weight homeostasis is a long-standing challenge requiring knowledge of energy intake, absorption and expenditure. Using measurements of respiratory gas exchange, indirect calorimetry can provide non-invasive estimates of whole-body energy expenditure. However, inconsistent measurement units and flawed data normalization methods have slowed progress in this field. This guide aims to establish consensus standards to unify indirect calorimetry experiments and their analysis for more consistent, meaningful and reproducible results. By establishing community-driven standards, we hope to facilitate data comparison across research datasets. This advance will allow the creation of an in-depth, machine-readable data repository built on shared standards. This overdue initiative stands to markedly improve the accuracy and depth of efforts to interrogate mammalian metabolism. Data sharing according to established best practices will also accelerate the translation of basic findings into clinical applications for metabolic diseases afflicting global populations.

Mutations in the gene encoding Tectonic β-propeller repeat-containing repeat protein 2 (TECPR2) cause hereditary sensory and autonomic neuropathy subtype 9 (HSAN9) which is a fatal neurodevelopmental and neurodegenerative disorder involving the sensory and peripheral nervous system. TECPR2 is ubiquitously expressed and linked to trafficking and sorting within the cell, however, its functional role remains poorly defined. Moreover, molecular insights into pathogenic mechanisms underlying HSAN9 are lacking. Here, we report a novel mouse model which harbors a HSAN9-associated nonsense mutation that causes loss of TECPR2 expression. Mice show altered gait, highly region-specific axonal dystrophy, and extensive local gliosis. The affected medulla area prominently features swollen axons filled with amorphous protein aggregates, glycogen granules, single and double membrane vesicles as well as aberrant organelles including ER and mitochondria whose proteome is distinctly altered. Despite the locally restricted pathology the neuronal demise is detectable in the cerebrospinal fluid and responded to by damage-associated microglia. However, their capacity to clear neuronal debris seems attenuated. Overall, neuronal and microglia phenotypes point to a dysfunctional endolysosomal system when TECPR2 is missing. This was confirmed in TECPR2 knockout cells and linked to TECPR2's interaction with the homotypic fusion and protein sorting (HOPS)-tethering complex. Collectively, we uncovered a role of TECPR2 in endolysosome maintenance which seems relevant for healthy neurons in a particular brain region.

PURPOSE: This study investigates genes contributing to late-adult corneal dystrophies (LACDs) in aged mice, with potential implications for late-onset corneal dystrophies (CDs) in humans. METHODS: The International Mouse Phenotyping Consortium (IMPC) database, containing data from 8901 knockout mouse lines, was filtered to include late-adult mice (49+ weeks) with significant (P < 0.0001) CD phenotypes. Candidate genes were mapped to human orthologs using the Mouse Genome Informatics group, with expression analyzed via PLAE and a literature review for prior CD associations. Comparative analyses of LACD genes from IMPC and established human CD genes from IC3D included protein interactions (STRING), biological processes (PANTHER), and molecular pathways (KEGG). RESULTS: Analysis identified 14 genes linked to late-adult abnormal corneal phenotypes. Of these, 2 genes were previously associated with CDs in humans, while 12 were novel. Seven of the 14 genes (50%) were expressed in the human cornea based on single-cell transcriptomics. Protein-protein interactions via STRING showed several significant interactions with known human CD genes. PANTHER analysis identified six biological processes shared with established human CD genes. Two genes (Rgs2 and Galnt9) were involved in pathways related to human corneal diseases, including cGMP-PKG signaling, mucin-type O-glycan biosynthesis, and oxytocin signaling. Other candidates were implicated in pathways such as pluripotency of stem cells, MAPK signaling, WNT signaling, actin cytoskeleton regulation, and cellular senescence. CONCLUSIONS: This study identified 14 genes linked to LACD in knockout mice, 12 of which are novel in corneal biology. These genes may serve as potential therapeutic targets for treating corneal diseases in aging human populations.

Endurance exercise reduces the risk of metabolic diseases by improving skeletal muscle metabolism, particularly in individuals with overweight and obesity. As biological sex impacts glucose and fatty acid handling in skeletal muscle, we hypothesized sex differences at the transcriptomic and proteomic level in the acute response to exercise and after an 8-week exercise intervention. We analyzed skeletal muscle biopsies from 25 sedentary subjects (16f/9m) with overweight and obesity using transcriptomics and proteomics at baseline, after acute exercise, and following an 8-week endurance training program. Regulation of sex-specific differences was studied in primary myotubes from the donors. At baseline, differentially methylated CpG-sites potentially explain up to 59% of transcriptomic and 67% of proteomic sex differences. Differences were dominated by higher abundance of fast-twitch fiber type proteins, and transcripts and proteins regulating glycogen degradation and glycolysis in males. Females showed higher abundance of proteins regulating fatty acid uptake and storage. Acute exercise induced stress-responsive transcripts and serum myoglobin predominantly in males. Both sexes adapted to 8-week endurance training by upregulating mitochondrial proteins involved in TCA cycle, oxidative phosphorylation, and β-oxidation. Training equalized fast-twitch fiber type protein levels, mainly by reducing them in males. In vivo sex differences in autosomal genes were poorly retained in myotubes but partially restored by sex hormone treatment. In conclusion, our findings highlight sex-specific molecular signatures that reflect known differences in glucose and lipid metabolism between female and male skeletal muscle. After just 8 weeks of endurance training, these sex differences were attenuated, suggesting a convergence towards a shared beneficial adaptation at the molecular level.

The pig is a valuable animal model in diabetes research; however, standardized protocols are essential for evaluating in vivo metabolism. Here, we present a protocol for in vivo assessment of glucose control and insulin secretion and sensitivity in the pig. We describe steps for catheter implantation, testing of intravenous glucose tolerance, performance of hyperinsulinemic-euglycemic clamps (HECs) and hyperglycemic clamps (HGCs), and blood processing. We then detail procedures for analysis of plasma glucose, insulin, glucagon, and C-peptide concentrations as well as data analysis. For complete details on the use and execution of this protocol, please refer to Renner et al.1 and Renner et al.2.

Ensuring the quality and reproducibility of biological resources is essential for advancing biomedical research and upholding animal welfare standards. The European Mouse Mutant Archive (EMMA), part of the INFRAFRONTIER research infrastructure, plays a key role in this effort by cryopreserving scientifically validated mutant mouse and rat strains and making them accessible to the global scientific community. To further enhance its processes and promote transparency, INFRAFRONTIER/EMMA has developed a set of ten Quality Principles specifically tailored to the unique requirements of cryopreserved rodent mutant strains. These principles guide EMMA's workflows by providing a structured yet flexible quality framework across its distributed nodes. They encompass both general standards-such as adherence to the 3Rs (Replace, Reduce, Refine), staff competence, and continuous improvement-and more specific areas including scientific evaluation, data curation, and intellectual property rights. Each principle is presented with contextual background, defined requirements, practical recommendations, and key references. This initiative aims to strengthen the reliability, ethical integrity, and reproducibility of preclinical research resources.