Tissue-specific Effects Research Articles

P0088 3D tissue-level analysis of intestinal T cell dynamics reveals dual effects of etrasimod on recruitment and tissue exit in experimental colitis

Abstract Background Sphingosin-1-phosphate (S1P) receptor (S1PR) agonists are a novel class of anti-trafficking agents approved for the treatment of ulcerative colitis. These compounds induce T lymphocyte sequestration in secondary lymphoid organs, reducing their availability in peripheral blood and presumably in inflamed intestinal tissue. However, direct evidence for their effects on T cell dynamics within intestinal tissue is lacking. Moreover, while S1PR-dependent mechanisms regulate T cell egress from the gut, it remains unclear whether S1PR agonists modulate this process. This limited understanding of tissue-specific effects presents a crucial barrier to comprehending their full therapeutic mechanism. Methods We developed a comprehensive volumetric imaging platform to investigate tissue-level mechanisms of colitis within the complex three-dimensional architecture of the intestine. Using the T cell transfer colitis model, mice were treated with etrasimod or vehicle control. Full-thickness colon samples underwent tissue clearing and whole-mount immunofluorescence for T cell markers. Advanced light-sheet and volumetric confocal microscopy, combined with machine learning-based image analysis, enabled three-dimensional reconstruction of T cell distributions and lymphatic networks, allowing for quantitative histocytometry and spatial mapping of immune cell dynamics. Results T cell transfer colitis induced substantial lymphocyte infiltration in the colon, with T cells forming both distinct clusters and diffuse distributions throughout the tissue. The presence of numerous T cells within lymphatic vessels indicated active tissue egress, suggesting that T cell accumulation reflects a dynamic balance between recruitment and exit (Figure 1). Etrasimod treatment not only reduced overall T cell infiltration but also markedly altered their spatial distribution pattern. Notably, we observed a decreased proportion of T cells within lymphatic vessels, coupled with increased accumulation of T cells in proximity to lymphatic structures, indicating a previously unrecognized effect on tissue exit dynamics. Conclusion Our advanced volumetric imaging approach revealed novel insights into a potential dual mechanism of etrasimod in inflammatory bowel disease. Beyond reducing lymphocyte recruitment, etrasimod appears to create a tissue exit block, effectively trapping T cells within the intestinal compartment. These findings raise important questions about how enforced tissue residency influences local inflammatory circuits and may guide optimization of therapeutic strategies.

Tissue-specific effects of dietary protein on cellular senescence are mediated by branched-chain amino acids.

Dietary protein is a key regulator of healthy aging in both mice and humans. In mice, reducing dietary levels of the branched-chain amino acids (BCAAs) recapitulates many of the benefits of a low protein diet; BCAA-restricted diets extend lifespan, reduce frailty, and improve metabolic health, while BCAA supplementation shortens lifespan, promotes obesity, and impairs glycemic control. Recently, high protein diets have been shown to promote cellular senescence, a hallmark of aging implicated in many age-related diseases, in the liver of mice. Here, we test the hypothesis that the effects of high protein diets on metabolic health and on cell senescence are mediated by BCAAs. We find that reducing dietary levels of BCAAs protects male and female mice from the negative metabolic consequences of both normal and high protein diets. Further, we identify tissue-specific effects of BCAAs on cellular senescence, with restriction of all three BCAAs - but not individual BCAAs - protecting from hepatic cellular senescence while potentiating cell senescence in white adipose tissue. We find that the effects of BCAAs on hepatic cellular senescence are cell-autonomous, with lower levels of BCAAs protecting cultured cells from antimycin-A induced senescence. Our results demonstrate a direct effect of a specific dietary component on a hallmark of aging and suggest that cellular senescence may be highly susceptible to dietary interventions.

Tissue-specific modulation of NADH consumption as an anti-aging intervention in Drosophila.

Aging is characterized by extensive metabolic dysregulation. Redox coenzyme nicotinamide adenine dinucleotide (NAD) can exist in oxidized (NAD+) or reduced (NADH) states, which together form a key NADH/NAD+ redox pair. Total levels of NAD decline with age in a tissue-specific manner, thereby playing a significant role in the aging process. Supplementation with NAD precursors boosts total cellular NAD levels and provides some therapeutic benefits in human clinical trials. However, supplementation studies cannot determine tissue-specific effects of an altered NADH/NAD+ ratio. Here, we created transgenic Drosophila expressing a genetically encoded xenotopic tool LbNOX to directly manipulate the cellular NADH/NAD+ ratio. We found that LbNOX expression in Drosophila impacts both NAD(H) and NADP(H) metabolites in a sex-specific manner. LbNOX rescues neuronal cell death induced by the expression of mutated alpha-B crystallin in the Drosophila eye, a widely used system to study reductive stress. Utilizing LbNOX, we demonstrate that targeting redox NAD metabolism in different tissues may have drastically different outcomes, as the expression of LbNOX solely in the muscle is much more effective for rescuing paraquat-induced oxidative stress compared to whole-body expression. Excitingly, we demonstrate that perturbing NAD(P) metabolism in non-neuronal tissues is sufficient to rejuvenate sleep profiles in aged flies to a youthful state. In summary, we used xenotopic tool LbNOX to identify tissues and metabolic processes which benefited the most from the modulation of the NAD metabolism thereby highlighting important aspects of rebalancing the NAD and NADP pools, all of which can be translated into novel designs of NAD-related human clinical trials.

Multi-omic analysis of biological aging biomarkers in long-term calorie restriction and endurance exercise practitioners: A cross-sectional study.

Calorie restriction (CR) and physical exercise (EX) are well-established interventions known to extend health span and lifespan in animal models. However, their impact on human biological aging remains unclear. With recent advances in omics technologies and biological age (BioAge) metrics, it is now possible to assess the impact of these lifestyle interventions without the need for long-term follow-up. This study compared BioAge biomarkers in 41 middle-aged and older adult long-term CR practitioners, 41 age- and sex-matched endurance athletes (EX), and 35 sedentary controls consuming Western diets (WD), through PhenoAge: a composite score derived from nine blood-biomarkers. Additionally, a subset of participants (12 CR, 11 EX, and 12 WD) underwent multi-omic profiling, including DNA methylation and RNAseq of colon mucosa, blood metabolomics, and stool metagenomics. A group of six young WD subjects (yWD) served as a reference for BioAge calculation using Mahalanobis distance across six omic layers. The results demonstrated consistently lower BioAge biomarkers in both CR and EX groups compared to WD controls across all layers. CR participants exhibited lower BioAge in gut microbiome and blood-derived omics, while EX participants had lower BioAge in colon mucosa-derived epigenetic and transcriptomic markers, suggesting potential tissue-specific effects. Multi-omic pathway enrichment analyses suggested both shared and intervention-specific mechanisms, including oxidative stress and basal transcription as common pathways, with ether lipid metabolism uniquely enriched in CR. Despite limitations due to sample size, these findings contribute to the broader understanding of the potential anti-aging effects of CR and EX, offering promising directions for further research.

Intestinal Cyp24a1 regulates vitamin D locally independent of systemic regulation by renal Cyp24a1 in mice.

Vitamin D regulates mineral homeostasis. The most biologically active form of vitamin D, 1,25-dihydroxyvitamin D (1,25D), is synthesized by CYP27B1 from 25-dihydroxyvitamin D (25D) and inactivated by CYP24A1. Human monogenic diseases and genome-wide association studies support a critical role for CYP24A1 in regulation of mineral homeostasis, but little is known about its tissue-specific effects. Here, we describe the responses of mice with inducible global deletion, kidney-specific, and intestine-specific deletion of Cyp24a1 to dietary calcium challenge and chronic kidney disease (CKD). Global and kidney-specific Cyp24a1 deletion caused similar syndromes of systemic vitamin D intoxication: elevated circulating 1,25D, 25D and fibroblast growth factor 23 (FGF23), activation of vitamin D target genes in the kidney and intestine, hypercalcemia, and suppressed parathyroid hormone (PTH). In contrast, mice with intestine-specific Cyp24a1 deletion demonstrated activation of vitamin D target genes exclusively in the intestine despite no changes in systemic vitamin D levels. In response to a high calcium diet, PTH was suppressed despite normal serum calcium. In mice with CKD, intestinal Cyp24a1 deletion decreased PTH and FGF23 without precipitating hypercalcemia. These results implicate kidney CYP24A1 in systemic vitamin D regulation while independent local effects of intestinal CYP24A1 could be targeted to treat secondary hyperparathyroidism in CKD.

Assessment of ComBat Harmonization Performance on Structural Magnetic Resonance Imaging Measurements.

Data aggregation across multiple research centers is gaining importance in the context of MRI research, driving diverse high-dimensional datasets to form large-scale heterogeneous sample, increasing statistical power and relevance of machine learning and deep learning algorithm. Site-related effects have been demonstrated to introduce bias in MRI features and confound subsequent analyses. Although Combating Batch (ComBat) technique has been recently reported to successfully harmonize multi-scale neuroimaging features, its performance assessments are still limited and largely based on qualitative visualizations and statistical analyses. In this study, we stand out by using a robust cross-validation approach to assess ComBat performances applied on volume- and surface-based measures acquired across three sites. A machine learning approach based on Multi-Class Gaussian Process Classifier was applied to predict imaging site based on raw and harmonized brain features, providing quantitative insights into ComBat effectiveness, and verifying the association between biological covariates and harmonized brain features. Our findings showed differences in terms of ComBat performances across measures of regional brain morphology, demonstrating tissue specific site effect modeling. ComBat adjustment of site effects also varied across regional level of each specific volume-based and surface-based measures. ComBat effectively eliminates unwanted data site-related variability, by maintaining or even enhancing data association with biological factors. Of note, ComBat has demonstrated flexibility and robustness of application on unseen independent gray matter volume data from the same sites.

Multielectrode catheter-based pulsed electric field vs. cryoballoon for atrial fibrillation ablation: a systematic review and meta-analysis.

Pulsed field ablation (PFA) is an innovative technology recently adopted for the treatment of atrial fibrillation (AF). Preclinical and clinical studies have reported a remarkable safety profile, as a result of its tissue-specific effect targeting cardiomyocytes and sparing adjacent tissues. Single-shot pentaspline system was the first PFA device to receive regulatory approval. We performed a meta-analysis to compare the efficacy and safety of PFA with the single-shot pentaspline system vs. currently available second-/third-/fourth-generation cryoballoon ablation (CRYO) technologies. We systematically searched electronic databases for studies focusing on AF ablation employing the PFA single-shot pentaspline system or second-/third-/fourth-generation CRYO technologies. The primary endpoints were acute procedural success assessed on a vein and patient basis. Safety endpoints included overall periprocedural complications and major periprocedural complications. We also compared procedural, fluoroscopy times, and freedom from atrial tachyarrhythmias (ATs) at follow-up (secondary endpoints). Twenty and 70 studies were included for PFA and CRYO, respectively. Pulsed field ablation demonstrated greater acute procedural success on a vein basis (99.9% vs. 99.1%; P < 0.001), as well as per patient (99.5% vs. 98.4%; P < 0.001). Pulsed field ablation yielded lower overall periprocedural complications (3.1% vs. 5.6%; P < 0.001), shorter procedural time (75.9 min vs. 105.6 min; P < 0.001), and fluoroscopy time (14.2 min vs. 18.9 min; P < 0.001) compared with CRYO. No differences were found for major periprocedural complications (1.2% vs. 1.0%; P = 0.46) and freedom from ATs at 1 year (82.3% vs. 80.3%; log-rank P = 0.61). Pulsed field ablation contributed to higher acute procedural success and safety compared with CRYO. No statistically significant differences in AT recurrence at 1-year follow-up were observed.

Tissue-Specific Effects of Aging on Repeat-Mediated Mutation Hotspots In Vivo.

Aging constitutes complex and dynamic alterations in molecular and physiological processes and is associated with numerous disorders, in part due to increased genetic instability. The aging population is projected to double by 2050, underscoring the urgent need to better understand the relationships between aging and age-related disorders. Repetitive DNA elements are intrinsic sources of genetic instability and have been found to co-localize with mutation hotspots in human cancer genomes. In this study, we explored the relationship between aging and DNA repeat-mediated genetic instability in vivo using an H-DNA-forming mirror-repeat sequence from the cancer-associated human c-MYC gene. Utilizing a unique mutation-reporter mouse model, we observed tissue-specific effects of aging on H-DNA-induced genetic instability, with mutation frequencies increasing in spleen tissues and remaining unchanged in testis tissues. Analysis of the mutation spectra revealed large deletion mutations as the primary contributor to increasing H-DNA-induced mutations, supported by increased cleavage activity of H-DNA structures in aged spleen tissues. Our findings demonstrate that aging has distinct tissue-specific effects on repeat-mediated, cancer-associated mutations, providing insights into the complex relationship between aging and cancer.

The impact of inactivation of the GH/IGF axis during aging on healthspan.

Several mouse lines with congenital growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis disruption have shown improved health and extended lifespan. The current study investigated how inactivating this axis, specifically during aging, impacts the healthspan. We used a tamoxifen-inducible global GH receptor (GHR) knockout mouse model starting at 12 months and followed the mice until 24 months of age (iGHRKO12-24 mice). We found sex- and tissue-specific effects, with some being pro-aging and others anti-aging. Measuring an array of cytokines in serum revealed that inactivation of the GH/IGF-1 axis at 12 months did not affect systemic inflammation during aging. On the other hand, hypothalamic inflammation was significantly reduced in iGHRKO12-24 mice, evidenced by GFAP+ (glial fibrillary acidic protein, a marker of astrocytes) and Iba-1+ (a marker for microglia). Liver RNAseq analysis indicated feminization of the male transcriptome, with significant changes in the expression of monooxygenase, sulfotransferase, and solute-carrier-transporter gene clusters. Finally, we found impaired bone morphology, more pronounced in male iGHRKO12-24 mice and correlated with GH/IGF-1 inactivation onset age. We conclude that inhibiting the GH/IGF-1 axis during aging only partially preserves the beneficial healthspan effects observed with congenital GH deficiency.

Deciphering the tissue-specific functional effect of Alzheimer risk SNPs with deep genome annotation

Alzheimer’s disease (AD) is a highly heritable brain dementia, along with substantial failure of cognitive function. Large-scale genome-wide association studies (GWASs) have led to a set of SNPs significantly associated with AD and related traits. GWAS hits usually emerge as clusters where a lead SNP with the highest significance is surrounded by other less significant neighboring SNPs. Although functionality is not guaranteed even with the strongest associations in GWASs, lead SNPs have historically been the focus of the field, with the remaining associations inferred to be redundant. Recent deep genome annotation tools enable the prediction of function from a segment of a DNA sequence with significantly improved precision, which allows in-silico mutagenesis to interrogate the functional effect of SNP alleles. In this project, we explored the impact of top AD GWAS hits around APOE region on chromatin functions and whether it will be altered by the genetic context (i.e., alleles of neighboring SNPs). Our results showed that highly correlated SNPs in the same LD block could have distinct impacts on downstream functions. Although some GWAS lead SNPs showed dominant functional effects regardless of the neighborhood SNP alleles, several other SNPs did exhibit enhanced loss or gain of function under certain genetic contexts, suggesting potential additional information hidden in the LD blocks.

Considerations for Cell Type Heterogeneity in Pediatric Salivary DNA Methylation Analyses: Comparison of Reference Panels & Stratification by Estimated Cell Type Proportion.

Saliva is a widely used sample in epigenetic research with children due to its non-invasive nature. Since DNA methylation (DNAm) profile is cell type (CT) specific, salivary DNAm associations with exposures may be influenced by CT compositions, which is highly variable in saliva as it contains immune and buccal epithelial cells (BEC). Reference-based CT deconvolution and statistically adjusting estimated CT in DNAm analyses have become an increasingly common practice. However, careful examinations of how different reference panels may affect DNAm results and alternative approaches (e.g., stratification) are lacking. To scrutinize the best analytical strategies on pediatric salivary DNAm, the current study used 529 salivary DNAm samples obtained from children (mean age = 7.26 years, SD = 0.26 years) in the Family Life Project. Our results showed higher estimated CT variability with child than adult reference panels and highlighted the impact of these estimated CT discrepancies on DNAm associations with social variables (socioeconomic status). Stratifying salivary DNAm samples by BEC proportions detected a larger number of significant associations with biological variables (sex) and tissue-specific effect with cotinine level, a tobacco smoke-exposure biomarker. We provide analytical recommendations for future epigenetic research involving pediatric saliva samples.

ApoE Receptor-2 R952Q Variant in Macrophages Elevates Soluble LRP1 to Potentiate Hyperlipidemia and Accelerate Atherosclerosis in Mice.

apoER2 (apolipoprotein E receptor-2) is a transmembrane receptor in the low-density lipoprotein receptor (LDLR) family with unique tissue expression. A single-nucleotide polymorphism that encodes the R952Q sequence variant has been associated with elevated plasma cholesterol levels and increased myocardial infarction risk in humans. The objective of this study was to delineate the mechanism underlying the association between the apoER2 R952Q variant and increased atherosclerosis risk. An apoER2 R952Q mouse model was generated using a CRISPR/Cas9 strategy, intercrossed with LDLR knockout mice, followed by feeding a Western-type high-fat high-cholesterol diet for 16 weeks. Atherosclerosis was investigated by immunohistology. Plasma lipids and lipid distributions among the various lipoprotein classes were analyzed by colorimetric assay. Tissue-specific effects of the R952Q sequence variant on atherosclerosis were analyzed by bone marrow transplant studies. sLRP1 (soluble low-density lipoprotein receptor-related protein 1) was measured in plasma and conditioned media from bone marrow-derived macrophages by ELISA and GST-RAP (glutathione S-transferase-receptor-associated protein) pull-down, respectively. P38 MAPK (mitogen-activated protein kinase) phosphorylation in VLDL (very-low-density lipoprotein)-treated macrophages was determined by Western blot analysis. Consistent with observations in humans with this sequence variant, the apoER2 R952Q mutation exacerbated diet-induced hypercholesterolemia, via impediment of plasma triglyceride-rich lipoprotein clearance, to accelerate atherosclerosis in Western diet-fed LDLR knockout mice. Reciprocal bone marrow transplant experiments revealed that the apoER2 R952Q mutation in bone marrow-derived cells instead of non-bone marrow-derived cells was responsible for the increase in hypercholesterolemia and atherosclerosis. Additional data showed that the apoER2 R952Q mutation in macrophages promotes VLDL-induced LRP1 (low-density lipoprotein receptor-related protein 1) shedding in a p38 MAPK-dependent manner. The apoER2 R952Q mouse model recapitulates characteristics observed in human disease. The underlying mechanism is that the apoER2 R952Q mutation in macrophages exacerbates VLDL-stimulated sLRP1 production in a p38 MAPK-dependent manner, resulting in its competition with cell surface LRP1 to impede triglyceride-rich lipoprotein clearance, thereby resulting in increased hypercholesterolemia and accelerated atherosclerosis.

Acute kidney injury after catheter ablation of atrial fibrillation: comparison between different energy sources

Abstract Introduction Pulsed field ablation (PFA) is an innovative technology recently adopted for the treatment of atrial fibrillation (AF). Preclinical and clinical studies have reported a reassuring safety profile, because of its tissue specific effect, sparing adjacent tissues. However, two cases of acute kidney injury (AKI) secondary to hemolysis after PFA have recently been reported. Purpose To compare the incidence of AKI and hemolysis after catheter ablation of AF using radiofrequency energy (RFA), cryo-balloon energy (CBA) and PFA using a pentaspline catheter. Method Patients undergoing catheter ablation of AF were consecutively enrolled in a prospective registry in a tertiary referral center between April 2010 and January 2024. Blood samples including renal parameters and hemolysis indicators were obtained prior to the procedure and the day after the procedure. AKI was defined as an increase in serum creatinine by 26.5 µmol/L within up to 10 days after the procedure . Results A total of 2602 patients (median age 64 years, 29.4% female) underwent catheter ablation for AF. 1707 (66.4%) were treated with RFA, 557 (21.7%) using CBA and 306 (11.9%) using PFA. Median net duration of ablation was 1669 (IQR 1207, 2164) seconds for RFA, 1046 (IQR 840, 1451) seconds for CBA and, 80 (IQR 48, 85) seconds (32 (IQR 19, 34) applications) for PFA. AKI was found in 21 (0.012%), 1 (0.002%) and 1 (0.003%) patients treated with RFA, CBA and PFA, respectively, p=0.245. The case with AKI after PFA received a total of 86 PFA applications. There was a significant positive correlation for the RFA group between the ablation duration and the creatinine level after the procedure, while there was no positive correlation for the CBA and PFA group (Figure). At least one hemolysis indicator (Bilirubin, LDH or Urea levels) was elevated the day after the procedure in 53.1%, 50.1% and 46.5% in the RFA, CBA and PFA group, respectively, p=0.12. Conclusion AKI appears to be very rare after PFA and comparable to thermal energy forms. Hemolysis does not seem to be dependent on the used energy source for pulmonary vein isolation. Minimal hemolysis occurs when PFA is applied as recommended by the manufacturer.Graphical Abstract

A multi-omics study of brain tissue transcription and DNA methylation revealing the genetic pathogenesis of ADHD.

Attention-deficit/hyperactivity disorder (ADHD) is a chronic psychiatric disease that often affects a patient's whole life. Research has found that genetics plays an important role in the development of ADHD. However, there is still a lack of knowledge about the tissue-specific causal effects of biological processes beyond gene expression, such as alternative splicing (AS) and DNA methylation (DNAm), on ADHD. In this paper, a multi-omics study was conducted to investigate the causal effects of the transcription and the DNAm on ADHD, by integrating ADHD genome-wide association data with quantitative trait loci data of gene expression, AS, and DNAm across 14 different brain tissues. The causal effects were estimated using four different two-sample Mendelian randomization methods. Finally, we also prioritized the expression of 866 genes showing significant causal effects, including COMMD5, ENSG00000271904, HYAL3, etc., within at least one brain tissue. We prioritized 966 unique genes that have statistically significant causal AS events, within at least one of the 14 different brain tissues. These genes include PPP1R16A, GGT7, TREM2, etc. Furthermore, through mediation analysis, 106 regulatory pathways were inferred where DNAm influences ADHD through gene expression or AS processes. Our research findings provide guidance for future experimental studies on the molecular mechanisms of ADHD development, and also put forward valuable knowledge for the prevention, diagnosis, and treatment of ADHD.

Insights on estetrol, the native estrogen: from contraception to hormone replacement therapy.

Estetrol (E4) is a natural estrogen that has recently emerged as new option for contraception and hormone replacement therapy (HRT). Unlike other estrogens, E4 primarily stimulates nuclear estrogen receptor alpha (ERα) and does not activate membrane ERα. For this reason, this novel estrogen has tissue-specific effects across various organs such as liver, vascular endothelium, mammary glands, brain, vagina, and uterus. The selective activation of the nuclear ERα results in distinct pharmacological properties that contribute to its unique therapeutic profile. Moreover, E4 shows minimal interaction with the hepatic cytochrome P450 enzyme system, leading to a favorable pharmacokinetic profile and a reduced potential for drug-drug interactions. Currently, E4 is commercially available in combination with drospirenone as a combined oral contraceptive and its application in HRT is undergoing late-stage clinical development. Many studies have demonstrated that E4 has a lower impact on hemostatic and metabolic parameters compared to other estrogens, potentially reducing the risk of adverse effects commonly associated with hormonal therapies such as thromboembolic events or dyslipidemia. Beyond its role in contraception and HRT, E4 shows promising therapeutic potential in other medical fields, including neuroprotection in neonatal hypoxic-ischemic encephalopathy, enhancement of hematopoietic stem cell transplantation outcomes and prostate cancer management. This review synthesizes the latest evidence on E4 primarily focusing on its pharmacological characteristics and clinical applications. The findings suggest that E4 versatility and peculiar mechanism of action may represent an important therapeutic option for a broad spectrum of medical conditions.

Recruitment of CXCR4+ type 1 innate lymphoid cells distinguishes sarcoidosis from other skin granulomatous diseases.

Sarcoidosis is a multiorgan granulomatous disease that lacks diagnostic biomarkers and targeted treatments. Using blood and skin from patients with sarcoid and non-sarcoid skin granulomas, we discovered that skin granulomas from different diseases exhibit unique immune cell recruitment and molecular signatures. Sarcoid skin granulomas were specifically enriched for type 1 innate lymphoid cells (ILC1s) and B cells and exhibited molecular programs associated with formation of mature tertiary lymphoid structures (TLSs), including increased CXCL12/CXCR4 signaling. Lung sarcoidosis granulomas also displayed similar immune cell recruitment. Thus, granuloma formation was not a generic molecular response. In addition to tissue-specific effects, patients with sarcoidosis exhibited an 8-fold increase in circulating ILC1s, which correlated with treatment status. Multiple immune cell types induced CXCL12/CXCR4 signaling in sarcoidosis, including Th1 T cells, macrophages, and ILCs. Mechanistically, CXCR4 inhibition reduced sarcoidosis-activated immune cell migration, and targeting CXCR4 or total ILCs attenuated granuloma formation in a noninfectious mouse model. Taken together, our results show that ILC1s are a tissue and circulating biomarker that distinguishes sarcoidosis from other skin granulomatous diseases. Repurposing existing CXCR4 inhibitors may offer a new targeted treatment for this devastating disease.

Spermidine supplementation influence on protective enzymes of Apis mellifera (Hymenoptera: Apidae).

Dietary supplementation has been proposed as a sustainable way to improve the health and resilience of honey bees (Apis mellifera, L.), as the decline in their numbers in recent decades has raised scientific, environmental, and economic concerns. Spermidine, a natural polyamine, has been shown to be a promising substance for honey bee supplementation, as its health-promoting effects have been demonstrated in numerous studies and in different organisms. As already shown, supplementation with spermidine at a certain concentration prolonged lifespan, reduced oxidative stress, and increased antioxidative capacity in honey bees. The aim of the present study was to investigate whether spermidine supplementation affects gene expression and/or enzyme activity of antioxidative and detoxification enzymes and immune response markers in honey bee workers. The different gene expression and enzyme activity patterns observed in abdominal and head tissues in response to spermidine supplementation suggest tissue-specific and concentration-dependent effects. In addition, the immune response markers suggest that spermidine has the ability to boost honey bee immunity. The observed changes make a valuable contribution to understanding the molecular mechanisms by which spermidine may exert its beneficial effects on the bee's health and lifespan. These results support the idea of the use of spermidine supplementation to promote bee health and resilience to environmental stressors, emphasizing that the dose must be carefully chosen to achieve a balance between the pro- and antioxidant effects of spermidine.

Adipose ADM2 ameliorates NAFLD via promotion of ceramide catabolism

The adipose tissue of mammals represents an important energy-storing and endocrine organ, and its dysfunction is relevant to the onset of several health problems, including non-alcoholic fatty liver disease (NAFLD). However, whether treatments targeting adipose dysfunction could alleviate NAFLD has not been well-studied. Adrenomedullin 2 (ADM2), belonging to the CGRP superfamily, is a protective peptide that has been shown to inhibit adipose dysfunction. To investigate the adipose tissue-specific effects of ADM2 on NAFLD, adipose-specific ADM2-overexpressing transgenic (aADM2-tg) mice were developed. When fed a high-fat diet, aADM2-tg mice displayed decreased hepatic triglyceride accumulation compared to wild-type mice, which was attributable to the inhibition of hepatic de novo lipogenesis. Results from lipidomics studies showed that ADM2 decreased ceramide levels in adipocytes through the upregulation of ACER2, which catalyzes ceramide catabolism. Mechanically, activation of adipocyte HIF2α was required for ADM2 to promote ACER2-dependent adipose ceramide catabolism as well as to decrease hepatic lipid accumulation. This study highlights the role of ADM2 and adipose-derived ceramide in NAFLD and suggests that its therapeutic targeting could alleviate disease symptoms.

Pervasive tissue-, genetic background-, and allele-specific gene expression effects in Drosophila melanogaster.

The pervasiveness of gene expression variation and its contribution to phenotypic variation and evolution is well known. This gene expression variation is context dependent, with differences in regulatory architecture often associated with intrinsic and environmental factors, and is modulated by regulatory elements that can act in cis (linked) or in trans (unlinked) relative to the genes they affect. So far, little is known about how this genetic variation affects the evolution of regulatory architecture among closely related tissues during population divergence. To address this question, we analyzed gene expression in the midgut, hindgut, and Malpighian tubule as well as microbiome composition in the two gut tissues in four Drosophila melanogaster strains and their F1 hybrids from two divergent populations: one from the derived, European range and one from the ancestral, African range. In both the transcriptome and microbiome data, we detected extensive tissue- and genetic background-specific effects, including effects of genetic background on overall tissue specificity. Tissue-specific effects were typically stronger than genetic background-specific effects, although the two gut tissues were not more similar to each other than to the Malpighian tubules. An examination of allele specific expression revealed that, while both cis and trans effects were more tissue-specific in genes expressed differentially between populations than genes with conserved expression, trans effects were more tissue-specific than cis effects. Despite there being highly variable regulatory architecture, this observation was robust across tissues and genetic backgrounds, suggesting that the expression of trans variation can be spatially fine-tuned as well as or better than cis variation during population divergence and yielding new insights into cis and trans regulatory evolution.

Activation of Nrf2 at Critical Windows of Development Alters Tissue-Specific Protein S-Glutathionylation in the Zebrafish (Danio rerio) Embryo.

Activation of Nrf2-the master regulator of antioxidative response-at different stages of embryonic development has been shown to result in changes in gene expression, but the tissue-specific and downstream effects of Nrf2 activation during development remain unclear. This work seeks to elucidate the tissue-specific Nrf2 cellular localization and the downstream changes in protein S-glutathionylation during critical windows of zebrafish (Danio rerio) development. Wild-type and mutant zebrafish embryos with a loss-of-function mutation in Nrf2a were treated with two canonical activators, sulforaphane (SFN; 40 µM) or tert-butylhydroquinone (tBHQ; 1 µM), for 6 h at either pharyngula, hatching, or the protruding-mouth stage. Nrf2a protein and S-glutathionylation were visualized in situ using immunohistochemistry. At the hatching stage, Nrf2a protein levels were decreased with SFN, but not tBHQ, exposure. Exposure to both activators, however, decreased downstream S-glutathionylation. Stage- and tissue-specific differences in Nrf2a protein and S-glutathionylation were identified in the pancreatic islet and liver. Protein S-glutathionylation in Nrf2a mutant fish was increased in the liver by both activators, but not the islets, indicating a tissue-specific and Nrf2a-dependent dysregulation. This work demonstrates that critical windows of exposure and Nrf2a activity may influence redox homeostasis and highlights the importance of considering tissue-specific outcomes and sensitivity in developmental redox biology.