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Development and validation of an LC-MS/MS method for the quantification of the KRASG12C inhibitor divarasib.

Divarasib is a newly developed covalent KRASG12C inhibitor, currently under clinical investigation in a phase 3 trial in patients with non-small cell lung cancer (NSCLC). At the moment, very limited pharmacokinetic data are publicly known. However, obtaining more insight into the pharmacokinetic properties of divarasib is important, since this may provide a better understanding of its efficacy and safety risks. Pre-clinical studies have been performed in mouse models to evaluate the effect of drug transporters and drug-metabolizing enzymes on the plasma exposure and tissue distribution of divarasib. Therefore, a reliable quantification method is required. To our knowledge, no bioanalytical assay of divarasib has been published yet. Therefore, in this study we developed and validated an assay to quantify divarasib in human plasma and in eight different mouse-related matrices, and partially in mouse plasma, using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was initially evaluated over a concentration range of 1-10,000 nM. However, due to carry-over observed at 10,000 nM, the validated calibration range was established at 1-2000 nM, with matrix-dependent LLOQs of 1-10 nM. Erlotinib was used as an internal standard and acetonitrile was utilized to perform protein precipitation as sample pretreatment. Divarasib demonstrated stability in human plasma and in mouse plasma and tissue homogenates under various experimental conditions. A pilot in vivo study showed the applicability of our validated LC-MS/MS method. Ongoing clinical trials may collect plasma samples, and this developed method enables quantification of divarasib in both mouse and human plasma samples.

Animals

Effects of CPAP on endothelial activation and fibrinolytic balance in coronary artery disease with obstructive sleep apnea: The RICCADSA randomized controlled trial.

BACKGROUND: Obstructive sleep apnea (OSA) promotes endothelial activation and a prothrombotic milieu through intermittent hypoxia, oxidative stress, and systemic inflammation, mechanisms closely linked to atherosclerosis progression. The vascular effects of continuous positive airway pressure (CPAP) therapy in patients with established coronary artery disease (CAD) remain incompletely understood. OBJECTIVE: To evaluate the longitudinal effects of CPAP treatment on endothelial adhesion molecules and fibrinolytic balance in patients with CAD and OSA. METHODS: In this randomized controlled analysis from the RICCADSA trial, 210 revascularized CAD patients with moderate-to-severe OSA were assigned to CPAP (n = 104) or no-CPAP (n = 106) and had available biomarker measurements at baseline and 12 months. Circulating intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and plasminogen activator inhibitor-1 (PAI-1) were assessed. Linear mixed-effects models were used to examine longitudinal changes and time-by-treatment interactions adjusted for cardiometabolic covariates. RESULTS: For ICAM-1, no significant time-by-treatment interaction was observed. For PAI-1, a borderline time-by-treatment interaction suggested a numerically smaller increase in the CPAP group compared with no-CPAP (p = 0.09). CPAP treatment was associated with a significantly greater reduction in VCAM-1 over time compared with no-CPAP (time-by-treatment interaction p = 0.045 in adjusted models). CONCLUSIONS: CPAP treatment was associated with selective modulation of vascular biomarkers in patients with CAD and OSA, characterized by attenuation of endothelial activation reflected by reduced VCAM-1 levels, while fibrinolytic imbalance appeared largely resistant to intervention. These findings support pathway-specific vascular responses to CPAP and provide mechanistic insight into residual atherosclerotic risk in this high-risk population.

Aged

Epigenetic Gene Networks Governing Immune State Transitions Across the Lifespan.

Immune function across development, tissue repair, aging, and disease depends not only on signaling pathways but also on epigenetic architectures that determine whether coordinated transcriptional programs can be accessed and resolved. Increasing evidence indicates that epigenetic gene networks regulate the accessibility and reversibility of semi-stable immune states, shaping plastic, homeostatic, reparative, and degenerative configurations. We propose the concept of epigenetic transition windows, defined as temporally and contextually restricted intervals during which epigenetic constraints are relaxed, permitting coordinated and reversible transitions between immune states. During development, these windows are broad and support immune tolerance and adaptive plasticity. In adulthood they become spatially and temporally restricted, preserving stability while enabling conditional adaptation. With aging, they progressively narrow, contributing to chronic inflammation, impaired repair, and increased vulnerability to neurodegeneration. Conversely, pathological persistence of regulatory permissiveness may underlie immune evasion and sustained plasticity in cancer. We outline operational genomic readouts for quantifying transition windows, including chromatin accessibility variance, enhancer switching dynamics, reversibility metrics, and cross-cell coordination indices, and derive experimentally testable predictions that distinguish this model from pathway-centric or damage-centric explanations. By reframing immune dysfunction as a failure of regulated state transition rather than excessive signaling alone, this framework integrates inflammaging, trained immunity, immune resolution failure, and tumor immune escape within a unified regulatory architecture and provides a systems-level perspective on immune adaptability across the lifespan.

Epigenesis, Genetic

Efficacy, Safety, and Pharmacokinetics of Upadacitinib Among Patients in East Asia With Moderately to Severely Active Ulcerative Colitis: A Post Hoc Subanalysis of Randomized Phase 3 Studies.

BACKGROUND AND AIM: Upadacitinib, a selective Janus kinase 1 inhibitor, is approved to treat moderately to severely active ulcerative colitis (UC). This post hoc subanalysis evaluated the efficacy, safety, and pharmacokinetics of upadacitinib in patients in East Asia. METHODS: U-ACHIEVE (UC1; NCT02819635) and U-ACCOMPLISH (UC2; NCT03653026) were Phase 3, multicenter, randomized, double-blind, induction studies evaluating upadacitinib 45 mg or placebo daily in adults with moderately to severely active UC. Clinical responders to 8 weeks of upadacitinib induction were eligible to receive upadacitinib 15 mg, upadacitinib 30 mg, or placebo daily in the 52-week U-ACHIEVE maintenance study (UC3; NCT02819635). Efficacy outcomes, safety, and pharmacokinetics were evaluated among East Asian patients. RESULTS: A higher proportion of East Asian patients achieved clinical remission with upadacitinib than placebo at induction Week 8 (UC1: n = 127, 31.4% vs. 7.3%; UC2: n = 114, 31.2% vs. 2.7%) and maintenance Week 52 (UC3: n = 184, upadacitinib 15 mg, 52.4%; upadacitinib 30 mg, 53.8%; placebo, 10.7%). Rates of endoscopic outcomes were higher with upadacitinib than with placebo across studies. No new safety signals were identified. Herpes zoster occurrences were low (UC1 and UC2: upadacitinib 45 mg, two events [in one patient]; placebo, zero events; UC3: upadacitinib 15 mg, five events; upadacitinib 30 mg, eight events; placebo, zero events). Pharmacokinetics and trends in the relationship between upadacitinib exposure and efficacy were consistent in the East Asian and global populations. CONCLUSION: Upadacitinib was generally well tolerated and effective for treating moderately to severely active UC in patients in East Asia, with a favorable benefit-risk profile consistent with the global population. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02819635, NCT03653026.

Humans

New Evidence in Heart Failure: 2026 Update.

Heart failure (HF) remains a major cause of morbidity, mortality, impaired quality of life and healthcare expenditure worldwide. The global burden of HF continues to increase due to population aging, improved survival, and the growing prevalence of cardiovascular, renal, and metabolic comorbidities. Simultaneously, the pace of scientific progress in HF has accelerated considerably. Recent advances have refined our understanding of HF epidemiology, prognosis, and disease trajectories, including emerging concepts of HF improvement, remission, and recovery. The Second Universal Definition of HF has also updated the classification framework, moving beyond the traditional ejection fraction-based categories. HF is now broadly classified into two major phenotypes: heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). Novel mechanistic insights highlight the role of inflammation, immune activation, metabolic dysfunction, mitochondrial biology, and multisystem interactions in HF progression. There has also been significant progress in the characterization and management of major comorbidities, including chronic kidney disease (CKD), diabetes, obesity, atrial fibrillation (AF), pulmonary hypertension, frailty, malnutrition, and cancer. Diagnostic innovations include novel biomarkers, multi-omics technologies, artificial intelligence-based approaches, advanced imaging techniques, congestion assessment tools, and emerging digital health solutions. Important advances have occurred in specific HF aetiologies, including cardiomyopathies, cardiac amyloidosis (CA), myocarditis, arrhythmia-induced cardiomyopathy (AiCM), and Chagas cardiomyopathy. Therapeutic developments continue to reshape HF management across the spectrum of left ventricular ejection fraction. Recent evidence has focused on optimization of guideline-directed medical therapy in HFrEF, expansion of evidence-based therapies in HFpEF, and growing roles for sodium-glucose cotransporter-2 inhibitors, finerenone, incretin-based therapies, and transcatheter valve interventions. Collectively, these advances support the transition from a predominantly phenotype-based approach towards a more personalized and biologically informed model of HF care, with the potential to further improve outcomes across the entire HF spectrum.

Journal Article

LitCTL1: A novel C-type lectin involved in the mucosal and cellular immunity of the common periwinkle Littorinalittorea.

C-type lectins (CTLs) are vital pattern-recognition receptors (PRRs) that mediate innate immune responses in mollusks, yet their characterization in Caenogastropoda, the largest gastropod group, remains limited. This study characterizes LitCTL1, a novel secreted single-domain C-type lectin from the common periwinkle, Littorina littorea. The 199-amino acid polypeptide contains a conserved carbohydrate recognition domain with canonical QPD and WND motifs and is predicted to form a homodimer. Uniquely, LitCTL1 was localized in both circulating hemocytes and mucus-secreting epithelial cells of the foot, mantle, and hypobranchial gland - the first report of such dual localization for a molluscan lectin, linking systemic and mucosal defense. Expression analysis revealed that LitCTL1 is constitutively expressed in hemocytes. Functional assays with recombinant LitCTL1 demonstrated its role as a potent opsonin with hemagglutinating activity, significantly enhancing hemocyte spreading and the phagocytosis of zymosan. Genomic analysis reveals that LitCTL1 belongs to a rapidly diversifying, genus-specific expansion distinct from conserved perlucin-like lineages. These results identify LitCTL1 as a key effector molecule in both systemic and mucosal innate immunity, likely reflecting an evolutionary adaptation to the microbial challenges of the intertidal environment.

Animals

Multi-omics analysis reveals stage-associated differences in gut immunity and microbiota between juvenile and adult common carp (Cyprinus carpio).

In vertebrates, the development of intestinal immunity is closely associated with dynamic changes in the gut microbiota. However, stage-associated differences in intestinal immunity and gut microbial communities remain poorly characterized in teleost fish. In this study, transcriptomic analysis combined with 16S rRNA gene sequencing was employed to characterize intestinal immunity and gut microbial communities in juvenile and adult common carp (Cyprinus carpio). Transcriptomic profiling revealed marked developmental differences in intestinal immune function. Juvenile carp exhibited a predominantly innate immune phenotype, characterized by elevated expression of pro-inflammatory cytokines, antimicrobial peptides, and lysozyme-related genes. This immune profile was accompanied by enhanced mucosal barrier function and a relatively pro-inflammatory intestinal environment. In contrast, adult carp displayed increased expression of genes associated with adaptive immunity, suggesting that adult common carp exhibit relatively stronger adaptive immune characteristics than juvenile fish. Gut microbiota analysis demonstrated significant stage-dependent differences in microbial diversity and community composition. Juvenile fish were enriched with bacterial taxa potentially associated with innate immune activation, whereas adult fish harbored distinct microbial communities linked to intestinal homeostasis and barrier maintenance. Furthermore, correlation analyses identified significant associations between specific microbial taxa and innate immune-related gene expression, suggesting a close association between gut microbiota composition and intestinal immune characteristics in juvenile and adult common carp. Collectively, these findings reveal stage-associated differences in intestinal immunity and gut microbial communities between juvenile and adult common carp, thereby providing insights into intestinal immune characteristics at different developmental stages in teleost fish.

Animals

Comparative safety of lipid-lowering drugs alone or in combination: insights from a systematic review and network meta-analysis.

BACKGROUND AND AIMS: Although the safety profile of lipid-lowering therapies (LLTs) is known, there are no comprehensive comparative assessments. We aimed to compare the risk of muscle-related events, diabetes, liver dysfunction, and cognitive disorders among LLTs through a network meta-analysis. METHODS AND RESULTS: Databases were searched from inception to May 2025. Eligible studies included adult patients, using statins, ezetimibe, PCSK9 monoclonal antibodies (PCSK9mAbs), inclisiran, bempedoic acid, or their combinations as intervention, reporting the information about any of the selected adverse events, a total sample size of ≥200 subjects, and had ≥1 month of intervention. Pooled estimates were assessed by fixed effects model within a frequentist setting. Pooled relative risks (RR) and their 95% confidence interval were estimated. A total of 303,397 subjects from 153 RCTs were included. Bempedoic acid ranked the lowest risk of myalgia (vs PCSK9mAbs, RR 0.80 [0.69, 0.93]). PCSK9mAbs were associated with lower incidence of creatine kinase (CK) elevation, diabetes, and liver dysfunction comparing to statins (statins vs PCSK9mAbs, RR 1.44 [1.14, 1.81], RR 1.13 [1.05, 1.22], and RR 1.38 [1.17, 1.62], respectively). In terms of muscle-related events and cognitive disorders, no significant risk differences were found among treatments and their combinations. CONCLUSIONS: PCSK9mAbs appear to have a more favourable safety profile regarding the risk of CK elevation, diabetes, and liver dysfunction. Bempedoic acid seem to be a better choice for subjects with high risk of myalgia. This information can be valuable when selecting therapy for specific patient subgroups at higher risk of certain adverse events.

Humans

Maternal age as a driver of genome instability: mechanisms linking aneuploidy, mutagenesis and mitochondrial dysfunction.

Advanced maternal age is a well-established risk factor for adverse reproductive outcomes due to increased rates of aneuploidy. However, emerging evidence indicates that the genetic consequences of maternal aging extend well beyond chromosome mis-segregation. Aging oocytes acquire a broad spectrum of genetic abnormalities, including maternally derived nuclear de novo mutations (DNMs) and mitochondrial DNA mutations, together with epigenetic dysregulation of DNA methylation and post-translational modification levels. These changes reflect the unique biology of the female germline in which oocytes remain arrested in meiotic prophase I for decades. Age-related deterioration of key processes, such as erosion of cohesion complexes, altered meiotic recombination, and weakened spindle assembly checkpoint surveillance collectively destabilize meiotic chromosome architecture, directly driving chromosome mis-segregation. At the same time, accumulation of endogenous DNA damage and declining DNA damage and repair processes increase the chances of transmitting lesions that can be converted into sequence-level mutations during the earliest embryonic divisions, when genome maintenance relies exclusively on maternal factors. High-resolution sequencing studies further demonstrate that maternal aging is associated with increased DNMs burden in both nuclear and mitochondrial DNA. Together, these findings support a model in which maternal aging is a driver of genome-wide instability that links aneuploidy and mutagenesis through shared defects in meiotic surveillance, declining DNA repair efficiency, and mitochondrial function. This framework positions delayed childbearing as a multifaceted genetic risk factor that extend beyond aneuploidy to include mutations and other genomic alterations that can impact intergenerational genetic risk.

Aneuploidy

How the microbiome shapes epigenetic trained memory in neuroinflammation: Implications for neurodegenerative diseases.

Neurodegenerative diseases are increasingly recognized as disorders involving immune dysregulation. However, the mechanisms underlying this dysfunction remain poorly characterized. Trained immunity has recently emerged as a potential contributor to immune dysregulation, particularly in neuroinflammation and neurodegenerative diseases, where trained immunity is the epigenetic reprogramming of innate immune responses following an initial inflammatory stimulus, which increases responses to subsequent exposures. In parallel, although the brain has traditionally been viewed as an immune-privileged organ, growing evidence indicates that peripheral immune activity exerts significant influence on neuroinflammation in the brain. A major driver of peripheral immunity is the microbiome. Therefore, this perspective aims to present a conceptual framework for a relationship between the microbiome, trained immunity, and neurodegenerative diseases. We first summarize evidence of trained immunity in the brain and its role in neurodegeneration. Next, we highlight the role of the microbiome in peripheral immune modulation and in trained immunity. Finally, we propose potential mechanisms through which the microbiome may induce or modulate trained immunity in the brain. These include: 1) immunogenic microbial metabolites that cross the blood-brain barrier and alter host cell epigenetics; 2) migration of peripherally trained myeloid cells into the brain; 3) viral infection-induced trained immunity that may predispose to neurodegeneration. Together, this perspective suggests that microbiome-induced trained immunity offers a novel mechanism linking peripheral immune regulation with neuroinflammation and neurodegeneration with implications for therapeutic targeting of epigenetic modification as a molecular prevention strategy for progression of neurodegeneration.

Humans

Integrin-Linked Kinases 1, 4, and 5 participate in cell wall-mediated innate immunity to leaf and root pathogens.

The cell wall integrity (CWI) pathway is triggered by plasma membrane-localized receptors in plant cells and serves to orchestrate responses to cell wall damage by initiating compensatory changes under stressful environments. The essential role of CWI maintenance as part of plants' interactions with pests or pathogens and during growth is well known. Nevertheless, CWI pathways remain to be fully characterized. Here, we show that altered Integrin-Linked Kinase 1 (ILK1) expression causes widespread defects in the transcriptional program activated by the bacterial elicitor flg22, primarily in genes associated with cell wall integrity and immunity. These transcriptional deficiencies are recapitulated in mutant lines with altered ILK4 or ILK5 expression. Analysis of molecular and cellular defenses in ilk mutants revealed reduced callose accumulation in leaves treated with bacterial (elf18) and plant (pep1) elicitors and increased pathogen susceptibility. Histochemical analysis of cell-wall-associated staining across diverse cells and organs of ilk mutants revealed modified lignin-associated patterns in the root xylem and altered calcofluor staining patterns in the seed coat. All ilk mutants exhibited altered root morphology due to mechano-touch and high-NaCl stress. Based on these results, we propose that ILKs contribute to pathways connecting elicitor-triggered immune signaling with cell-wall-associated stress responses and that ILK-related defense functions may extend to the cotton root-nematode interaction, while the mechanism remains to be elucidated.

Cell Wall

Efficacy of dapagliflozin on hepatic steatosis and fibrosis in patients with type 2 diabetes mellitus and metabolic dysfunction-associated steatotic liver disease: a pre-specified single-arm analysis from a randomized controlled trial.

AIM: To evaluate the association of dapagliflozin therapy with changes in hepatic steatosis and non-invasive fibrosis surrogate markers in patients with type 2 diabetes mellitus (T2DM) and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) over 12&#xa0;months. METHODS: This is a pre-specified single-arm analysis from a randomised, open-label, parallel-group trial. Of 54 participants randomised to dapagliflozin 10&#xa0;mg daily, 50 (92.6%) completed the 12-month follow-up and were included in the per-protocol analysis. Assessments at baseline, 3, 6, and 12&#xa0;months included transient elastography (CAP and LSM), ultrasonography, and biochemical tests. Primary endpoints were changes in hepatic steatosis (CAP) and non-invasive fibrosis surrogates (LSM). RESULTS: Significant reductions were observed in hepatic steatosis (CAP: 316.7 to 245.7&#xa0;dB/m; mean change&#xa0;-&#xa0;71.02&#xa0;dB/m, 95% CI: -63.4 to&#xa0;-&#xa0;78.6; p&#xa0;<&#xa0;0.001) and in liver stiffness as a non-invasive fibrosis surrogate (LSM: 8.59 to 7.28&#xa0;kPa; mean change&#xa0;-&#xa0;1.31&#xa0;kPa, 95% CI: -0.92 to&#xa0;-&#xa0;1.70; p&#xa0;<&#xa0;0.001). Improvements were also observed in glycaemic control, body weight, lipid profile, liver enzymes, ultrasonographic steatosis grading, and serum fibrosis markers. Genitourinary infections were the most frequently reported adverse events (32%); no serious adverse events were recorded. CONCLUSIONS: Dapagliflozin was associated with significant improvements in hepatic steatosis, non-invasive fibrosis surrogate markers, metabolic parameters, and liver function in T2DM patients with MASLD over 12&#xa0;months. These findings provide region-specific evidence for an Indian population and support further controlled investigation. However, these findings should be interpreted in light of the pre-specified single-arm design of this analysis, the open-label methodology, relatively small sample size, and the absence of liver biopsy confirmation.

Humans

GATA2 deficiency: enhancer deregulation, immune surveillance failure, and clonal evolution.

Germline mutations in GATA2 cause a syndromic inborn error of immunity characterized by cytopenia, infections, immune dysregulation, and a marked predisposition to myelodysplastic syndrome and acute myeloid leukemia. Initially defined by the DCML phenotype-dendritic cell, monocyte, B- and NK-cell deficiency-GATA2 deficiency is now recognized as a disorder of global immune-hematopoietic homeostasis. Recent multi-omics and experimental models reveal enhancer-driven inflammatory rewiring, IRF8-dependent lineage imbalance, and premature hematopoietic aging. In parallel, adaptive immune defects, including impaired B- and T-cell development and function, contribute to defective immune surveillance. These alterations not only explain susceptibility to infection but also shape clonal evolution and malignant transformation. Clinically, improved risk stratification and transplant outcomes underscore the importance of early recognition and monitoring of immune dysfunction. GATA2 deficiency thus represents a paradigm linking immune dysregulation, inflammatory stress, and cancer predisposition.

Humans

Efficacy and Safety of Rivaroxaban in Patients with Peripheral Artery Disease: A GRADE-assessed Systematic Review and Meta-Analysis.

BACKGROUND: Peripheral artery disease (PAD) is a common atherosclerotic disorder characterized by progressive arterial narrowing in the limbs. This study aims to determine the efficacy and safety of rivaroxaban, focusing on major cardiovascular events, limb outcomes, and bleeding risks. METHODS: PubMed, Cochrane, and EMBASE were searched for randomized controlled trials (RCTs) and nonrandomized comparative studies that compared rivaroxaban, either alone or in combination with aspirin, to placebo or standard care such as antiplatelet therapy. Risk ratios and hazard ratios with 95% confidence intervals were pooled using R v4.5.1 with an appropriate random-effects model applied. Subgroup analyses were performed according to rivaroxaban plus aspirin versus rivaroxaban alone. RESULTS: A total of 39,991 participants across 6 studies were included. Compared with control, use of rivaroxaban was linked to a significant reduction in composite efficacy outcomes (relative risk [RR] = 0.84, 95% confidence interval [CI] 0.78-0.91, P < 0.001), risk of acute limb ischemia (RR = 0.65, 95% CI 0.55-0.78, P < 0.001), and thromboembolism (RR = 0.60, 95% CI 0.38-0.97, P = 0.037). Although rivaroxaban plus aspirin failed to show a significant reduction in the risk of amputation, rivaroxaban alone reported a significant risk reduction (RR = 0.50, 95% CI 0.30-0.85, P = 0.003). However, its use was associated with a significantly higher risk of major bleeding (hazard ratio [HR] = 1.54, 95% CI 1.38-1.72, P < 0.001) and International Society on Thrombosis and Hemostasis-defined bleeding (RR = 1.45, 95% CI 1.19-1.76, P < 0.001). No significant differences were observed for stroke, myocardial infarction, major adverse limb events, fatal bleeding, mortality, or cardiovascular mortality. CONCLUSION: Rivaroxaban-based therapy reduced the trial-defined composite efficacy outcome, acute limb ischemia, and thromboembolism in patients with PAD, but increased the risk of major bleeding. These findings support individualized use of rivaroxaban-based therapy in carefully selected patients, balancing ischemic and limb-protective benefits against bleeding risk.

Humans

Immune dysregulation in depression and psychosis: summary of current evidence and future perspectives.

Despite compelling epidemiological, genetic and cellular evidence linking immune dysregulation to depression and schizophrenia (and other psychotic disorders), causality remains contested and no immune biomarker has yet demonstrated robust clinical utility. Emerging methodological approaches - from target trial emulation on observational data to functional genomics - offer a potential path towards precision immunopsychiatry and stratified immunomodulatory treatment.

Neuroimmunology

TNF-NF-&#x3ba;B signaling mediates immune-biomineralization crosstalk during shell repair under ocean acidification in Mytilus edulis.

Ocean acidification (OA) impairs biomineralization in bivalves, but its effects on immune-biomineralization crosstalk during shell repair remain unknown. Here, we exposed adult Mytilus edulis bearing standardized shell perforations to three pH levels (8.1, 7.9, and 7.7) for up to 40 days. OA slowed early repair and caused microstructural disorganization and an approximately 87% reduction of compressive strength at pH 7.7, yet the damaged area appeared largely closed by day 15, suggesting a decoupling between morphological closure and functional recovery. In addition, transcriptomic profiling of hemocytes and mantle tissue, based on an average of 6.5&#x202f;Gb of clean reads per sample mapped to the M. edulis reference genome (NCBI Assembly GCF_000511035.1), revealed that these shell-level defects were accompanied by coordinated immune and metabolic reprogramming. Hemocytes, the primary immune effector cells of bivalves, exhibited pH- and time-dependent shifts with moderate acidification (pH 7.9) promoting inflammatory transcripts, whereas severe acidification (pH 7.7) suppressed these signals while upregulating stress-associated pathways; both treatments consistently downregulated lysosomal proteases and NF-&#x3ba;B negative regulators. The mantle, a primarily mineralizing organ, paradoxically upregulated immune-related genes while suppressing oxidative phosphorylation and extracellular matrix pathways. This tissue-level imbalance, with hemocytes recruited but functionally constrained and mantle metabolically suppressed yet immunologically activated, points to TNF-NF-&#x3ba;B pathway modulation as a key mediator of shell repair under acidification. Our findings demonstrate that visible shell closure masks underlying structural and mechanical failure, and that immune regulation, rather than simple suppression or activation, critically shapes the repair outcome. These results advocate for multifunctional indicators beyond closure area to assess shell integrity in acidified marine environments.

Animals

Transcriptomic changes in the gut mucosa of fasting northern elephant seal pups reveal immune modulation during early microbiome establishment.

Fasting is an integral component of the life-history of many species. Following abrupt weaning, northern elephant seal pups (Mirounga angustirostris) undergo an extended post-weaning fast of approximately 60&#xa0;days. During this period, enteric bacterial diversity increases, suggesting that host immune regulation may facilitate the establishment of microbial communities. However, the molecular processes occurring within the intestinal mucosa during this transition remain poorly understood. To investigate these mechanisms, we characterized transcriptional changes in the enteric mucosa of male and female northern elephant seal pups sampled at weaning and after one month of fasting. Total RNA isolated from rectal swabs was sequenced and aligned to the Mirounga angustirostris reference genome. Differential gene expression and gene set enrichment analyses were used to identify genes and pathways associated with fasting and sex-specific responses. Fasting was accompanied primarily by transcriptional downregulation, including genes involved in antimicrobial defense, inflammation, protein turnover, and epithelial remodeling. In contrast, several genes associated with B-cell activity and immune recognition were upregulated. Gene Set Enrichment Analysis revealed coordinated activation of immune-regulatory pathways indicating dynamic modulation of intestinal immunity rather than generalized immune suppression. Pronounced sex-specific differences were also observed. Male pups exhibited transcriptional patterns consistent with enhanced immune tolerance, whereas females showed broader immune-pathway activation, including enrichment of pro-inflammatory and stress-response pathways. Several non-coding RNAs also displayed sex-specific changes in expression. Together, these findings suggest that fasting induces transcriptional remodeling of the gut and may contribute to immune regulation during a critical period of microbiome establishment in northern elephant seal pups.

Animals