Deficient Mice Research Articles

Early growth response-1, a dynamic conduit in cardiovascular disease

The transcription factor, early growth response-1 (Egr-1) is the product of a prototypic immediate-early gene that plays an integral role in the pathogenesis of multiple cardiovascular diseases. Egr-1 has been linked with atherogenesis, myocardial ischemia-reperfusion injury, cardiac fibrosis and heart failure. Egr-1 expression is triggered by a host of factors including cytokines, hormones, growth factors, hyperglycaemia, biomechanical forces and oxygen deprivation. Egr-1 is a molecular conduit that links changes in the cellular environment with the inducible expression of genes whose products play a causative role in this inflammatory disease. It is rapidly synthesised, undergoes post-translational modification, interacts with a range of cofactors and drives gene expression. Studies in Egr-1 deficient mice, animal models using DNAzymes, RNA interference, oligodeoxynucleotide decoys, antisense oligonucleotides, and new insights provided by technologies such as single cell RNA sequencing, have shaped our understanding of the importance of Egr-1 in the initiation and progression of cardiovascular disease. This article describes Egr-1's role in various cardiovascular settings and discusses potential mechanisms of action. Given the range of conditions linked to Egr-1, this zinc finger protein may serve as a therapeutic target for intervention.

A novel function for α-synuclein as a regulator of NCK2 in olfactory bulb: implications for its role in olfaction.

To investigate physiological function of α-synuclein is important for understanding its pathophysiological mechanism in synucleinopathies including Parkinson's disease. Employing knockout mice, we found that Snac/α-synuclein deletion induced aberrant projection of olfactory sensory neurons and hyposmia. We identified 9 axon guidance associated differentially expressed proteins using iTRAQbased Liquid Chromatograph Mass Spectrometer. NCK2 is most significantly down-regulated protein among them. We further found that either α-synuclein deletion or NCK2 deficiency induced Eph A4 inactivation. Re-expressing Snac/α-synuclein in its knockout neurons reversed the down-regulation of NCK2, as well as the inactivation of EphA4. Overexpression of Snac/α-synuclein in α-synuclein deleted mice reversed the down-regulation of NCK2 and pEphA4, and improved the olfactory impairment of mice. Correlation analysis showed that there is a significant correlation between the protein level of α-synuclein, NCK2, and pEphA4, respectively. Nonetheless, immunoprecipitation analysis showed that NCK2 was associated with both EphA4 and Rho A, suggesting that NCK2 as a scaffolding protein to modulate Eph A4/Rho A pathway. Moreover, Rho A activity was significantly lower in α-synuclein deficient mice. Thus, α-synuclein regulates olfactory neurons projection through NCK2 dependent EphA4/Rho A pathway. Malfunction of α-synuclein because of deletion may cause aberrant olfactory neurons projection. This extended our knowledge of α-synuclein functions, which may explain why olfaction is usually impaired in some synucleinopathies.

Abstract 4134975: ROS-Traf6-Yap Promotes the Development of Cardiac Hypertrophy

Introduction: Heart failure (HF) is caused by structural and functional abnormalities of the heart and is associated with high morbidity and mortality. Pathological myocardial hypertrophy accounts for a significant portion heart failure. The Yap protein was found to be responsive to mechanotransduction signals and can limit organ size by inducing cell cycle arrest during development. In the heart, pathological activation of Yap has been shown to drive cardiac hypertrophy, but regenerative activation of Yap can promote myocardial cell-cycle re-entry. However, how Yap is pathologically activated in the beating cardiomyocyte remains elusive. Hypothesis: ROS-Traf6 promotes the development of cardiac hypertrophy by activating Yap in a non-canonical fashion. Methods: Traf6 protein levels in heart failure patients biopsies as well as in various murine failing hearts were examined by immunofluorescence. Molecular interrogation of ROS-Traf6-Yap signaling axis was performed in primary neonatal rat cardiomyocytes (NRCM) and human induced pluripotent stem cell derived cardiomyocytes. Yap protein stability and activation by Traf6 was examined by immunoprecipitation, CHX induction, and point mutation. Myocardial specific Traf6 knockout and Yap mutant animals were used to evaluate Traf6-Yap signaling in vivo . Results: We found that Traf6 expression was significantly elevated in multiple heart failure models. Using the transverse aortic constriction (TAC)-induced cardiac hypertrophy model, pressure overload increased ROS levels which activated Traf6. Traf6 overexpression induced myocardial hypertrophy while knockdown blocked myocardial hypertrophy in Ang II treated NRCMs. Mechanistically, Traf6 binds to and ubiquitinates Yap-K234 – this promotes Yap protein stability and nuclear translocation evidenced by increase in phosphorylated Yap. Myocardial Traf6 deficiency prevents TAC-induced cardiac hypertrophy. Moreover, overexpression of Yap-K237 mutant did not restore TAC-induced cardiac hypertrophy in myocardial Yap deficient mice. Conclusions: Our results demonstrate that non-canonical Yap activation is responsible for pressure overload induced cardiac hypertrophy. Targeting of the newly identified ROS-Traf6-Yap signaling axis may provide a new approach to prevent pathogenic cardiac hypertrophy.

Abstract 4137996: Effects of Empagliflozin on diuresis in heart failure: Results from the CINNAMON-study and in-vivo experiments

Background and Purpose: Heart failure is associated with renal dysfunction suggesting a pathophysiological link between heart and kidney. Empagliflozin, a SGLT2 inhibitor, showed beneficial effects on both cardiovascular and renal endpoints. However, mechanistically, it is unclear if empagliflozin-dependent kidney protection is mediated via inhibition of tubular SGLT2 or more indirectly via improved cardiac function. We hypothesized that Empagliflozin treatment improves left ventricular ejection fraction (LVEF) independent of diuretic effect of renal SGLT2 inhibition. Methods: We evaluated NTproBNP, hematocrit, hemoglobin and bodyweight in patients with HF with reduced (n=32) and preserved ejection fraction (n=59) after 30 and 180 days (prospective, single-arm CINNAMON-study, DRKS00031101). Furthermore, we conducted transverse aortic constriction (TAC) or sham surgery in C57BL/6J (wildtype, WT) and SGLT2 deficient mice (SGLT2 -/- ). Animals received either Empagliflozin (10 mg/kg bodyweight) or vehicle by daily oral gavage. Water intake and output was evaluated by metabolic cages at 10 weeks and cardiac function by echocardiography. Results: Empagliflozin treatment reduced NT-proBNP levels and increased hematocrit and hemoglobin levels especially in patients with reduced ejection fraction (Fig. A-C). Surprisingly, there was no change in body weight (Fig. D), which would be expected if the diuretic effects were dominant. In mice after 10 weeks, echocardiography confirmed TAC induced pressure-overload, leading to reduced LVEF. Empagliflozin attenuated changes in LVEF (Fig. G) and improved diastolic dysfunction (isovolumetric relaxation time, data not shown). To test if direct inhibition of SGLT2 in the heart and kidney is mechanistically involved, TAC surgery was repeated in SGLT2-deficient mice (SGLT2-KO). In fact, exposure to TAC resulted in comparable reduction of LVEF in SGLT2-KO and Empagliflozin prevented this deterioration similar to WT mice (Fig. G vs. I). Surprisingly, Empagliflozin did not increase drinking and urine volume neither in wildtype nor in SGLT2 deficient mice, suggesting a mechanism of cardioprotection independent of diuretic effects. Conclusion and Outlook: This is the first study investigating the role of SGLT2 in Empagliflozin treated patients and mice with heart failure. Importantly, empagliflozin treatment prevented deterioration of LVEF independent of the presence of SGLT2 and diuresis.

TMOD-11. ADVANCED MRI ANALYSIS TO ASSESS CHEMO-RADIATION RESPONSE IN PEDIATRIC EPENDYMOMA MODELS

Abstract Pediatric Ependymoma (EPN) is an aggressive brain tumor for which the benefits of chemo-radiation (CR) therapy have yet to be established. Our team has previously reported behavior patterns of EPN, including high tumor cellularity, cytological anaplasia, high mitotic index, tumor necrosis, and the presence of inflammatory cells such as M2-type macrophages. Recently, we have established advanced MRI protocols and computational algorithms for cell- and vessel-size imaging. The goal of this study is to develop advanced MRI analysis for CR response biomarkers (including tumor size, cell- and vessel-size correlates, and texture analysis) in mice with patient-derived xenografts (PDX) of pediatric EPN. Female severely immune deficient (SCID) mice were used for intracranial orthotopical inoculation of disaggregated tumors from pediatric EPN patients. All multi-parametric MRI sequences (fast spin echo, FLAIR, diffusion weighted, quantitative T2- and r2*-maps) were acquired on a Bruker 9.4 Tesla MRI scanner prior to CR, followed by 2 days and 2 weeks after CR treatment. All radiation treatment was performed using an animal image-guided precision XRAD irradiator (2Gyx5days), using MRI and CT guided EPN localization with added 30 mg/kg 5-fluoracil. All MRI analysis was performed using Bruker ParaVision software and MATLAB based modeling. The sensitivity of T2w-MRI scans was 0.2 mm for the smallest tumor detected; the median tumor volume at baseline was 2.5 mm3. Untreated mice showed rapid progression of tumor growth from small to intermediate to large EPN. The increased tumor sizes in untreated EPN were characterized by low ADC, highly elevated blood vessel density and large tumor cell size. A significant decrease in vessel size density and an increase in inflammatory cells were seen as soon as 2 days after CR therapy. The late response (2 weeks post CR) is characterized by increased ADC values and decreased cell size, resulting in significantly decreased tumor volumes.

TMIC-44. ANDROGEN LOSS WEAKENS ANTI-TUMOR IMMUNITY AND ACCELERATES BRAIN TUMOR GROWTH

Abstract Many cancers, including glioblastoma (GBM), exhibit a male-biased incidence and outcome disparity. The underlying reasons for this sex bias are unclear but likely involve differences in tumor cell state and immune response. This effect is further influenced by sex hormones, including androgens, which have been shown to inhibit anti-tumor T cell immunity in other solid tumors. Using a series of pre-clinical models, we observed that androgens drive anti-tumor immunity in brain tumors, contrasting with their effect in other tumor types. Upon castration, tumor growth was accelerated in GBM and brain tumor models, while the opposite effect was observed when tumors were located outside the brain. This castration effect could be reversed by testosterone administration. Flow cytometry revealed decreased T cell function, indicated by reduced anti-tumor cytokines (IFNγ and TNFα), and increased T cell exhaustion in both tumors and peripheral tissues in castrated mice, suggesting systemic immunosuppression. Indeed, the survival difference was completely abrogated in T cell deficient mice (RAG1 knockout). Mechanistically, increased hypothalamus-pituitary-adrenal (HPA) axis activity in castrated mice was responsible for the observed systemic immunosuppression, particularly in those with brain tumors. Blocking glucocorticoid receptors reversed the accelerated tumor growth in castrated mice, indicating that elevated glucocorticoid signaling mediated the castration effect. This mechanism was brain-specific rather than GBM-specific, as hyperactivation of the HPA axis was also observed with intracranial implantation of non-GBM tumors. Neuroinflammation caused by brain tumors was stronger in castrated mice, and proinflammatory cytokines like IL-1 and TNF induced HPA axis hyperactivation. Together, these findings highlight that brain tumors drive distinct endocrine-mediated mechanisms in the androgen-deprived setting and highlight the importance of organ-specific effects on anti-tumor immunity.

Clotting promotes glioma growth and infiltration through activation of focal adhesion kinase.

The tumor architecture of high-grade gliomas is shaped by tumor cell necrosis, invasive growth and the leakage of a fibrin-rich edema from poorly organized tumor blood vessels. Here, we demonstrate a marked upregulation of clot formation in the interstitial spaces of tumor tissues from patients with glioblastoma while tumor-free brain is essentially devoid of fibrin. The accumulation of fibrin in tumor interstitial spaces is functionally relevant as we demonstrate increased infiltration and growth of primary glioblastoma cells after embedding in a 3-dimensional matrix made of fibrin ex vivo. Additionally, we detected accelerated tumor growth after implanting glioblastoma cells together with clotted plasma in brains of immune deficient mice while glioblastoma development in clotting-deficient hemophilia mice was delayed. Glioblastoma growth correlated with the outgrowth of invadopodia and their adhesive interactions with the 3-dimensional clot matrix, which was mediated by integrins β1 and β3 and their common downstream target focal adhesion kinase (FAK). Knocking down FAK with CRISPR Cas9 caused an upregulation of p21/p27 cell cycle inhibitors, strong growth inhibition in cultured glioblastoma cells and sustained anti-tumorigenic effects in orthotopic glioblastoma xenografts in vivo. These results go hand in hand with genomic data from The Cancer Genome Atlas that indicate increased clotting activity and reduced patient survival in glioma subgroups with high integrin β1 and β3 expression. We therefore conclude that clotting in glioma interstitial spaces provides tumor cells with a potent proliferative stimulus that can be reversed by targeting the adhesive machinery of glioblastoma cells via inhibition of FAK.

Increased exercise tolerance in humanized G6PD deficient mice

Glucose-6-phosphate dehydrogenase (G6PD) deficiency affects 500 million people globally, impacting red blood cell (RBC) antioxidant pathways and increasing susceptibility to hemolysis under oxidative stress. Despite the systemic generation of reactive oxygen species during exercise, the effects of exercise on individuals with G6PD deficiency remain poorly understood This study utilized humanized mouse models expressing the G6PD Mediterranean variant (S188F, with 10% enzymatic activity) to investigate exercise performance and molecular outcomes. Surprisingly, despite decreased enzyme activity, G6PD-deficient mice have faster critical speed (CS) compared to mice expressing human canonical G6PD. Post-exercise, deficient mice did not exhibit differences in RBC morphology or hemolysis, but had improved cardiac function, including cardiac output, stroke volume, sarcomere length and mitochondrial content. Proteomics analyses of cardiac and skeletal muscles (gastrocnemius, soleus) from G6PD deficient compared to sufficient mice revealed improvements in mitochondrial function and increased protein turnover via ubiquitination, especially for mitochondrial and structural myofibrillar proteins. Mass spectrometry-based metabolomics revealed alterations in energy metabolism and fatty acid oxidation. These findings challenge the traditional assumptions regarding hemolytic risk during exercise in G6PD deficiency, suggesting a potential metabolic advantage in exercise performance for individuals carrying non-canonical G6PD variants.

Metabolomics reveals the metabolic disturbance caused by arsenic in the mouse model of inflammatory bowel disease

Arsenic exposure has long been a significant global health concern due to its association with various human diseases. The adverse health effects of arsenic can be influenced by multiple factors, resulting in considerable individual variability. Individuals with inflammatory bowel disease (IBD) are particularly vulnerable to the effects of toxin exposure, yet the specific impact of arsenic in the context of IBD remains unclear. In this study, we employed a non-targeted metabolomics approach to investigate how arsenic exposure affects metabolic homeostasis in an IBD model using Helicobacter trogontum-infected interleukin-10 deficient mice. Our results demonstrated that arsenic exposure disrupted the balance of various metabolites, including tryptophan, polyunsaturated fatty acids, purine and pyrimidine metabolites, and branched-chain amino acids, in mice with colitis but not in those without colitis. Notably, several crucial metabolites involved in anti-inflammatory responses, oxidative stress, and energy metabolism were significantly altered in mice with colitis. These results indicate that arsenic exposure in an IBD context can lead to extensive metabolic disturbances, potentially exacerbating disease severity and impacting overall health. This study underscores the necessity of evaluating arsenic toxicity in relation to IBD to better understand and mitigate associated health risks.

All-in-one AAV-mediated Nrl gene inactivation rescues retinal degeneration in Pde6a mice.

Retinitis pigmentosa (RP) is a complex group of inherited retinal diseases characterized by progressive death of photoreceptor cells and eventual blindness. Pde6a, which encodes a cGMP-specific phosphodiesterase, is a crucial pathogenic gene for autosomal recessive RP (RP43); there is no effective therapy for this form of RP. The compact CRISPR/SaCas9 system, which can be packaged into a single adeno-associated virus, holds promise for simplifying effective gene therapy. Here, we demonstrated that all-in-one AAV-SaCas9-mediated Nrl gene inactivation can efficiently prevent retinal degeneration in a RP mouse model with Pde6anmf363/nmf363 mutation. We screened single guide RNAs (sgRNAs) capable of efficiently editing mouse Nrl gene in N2a cells and then achieved effective gene editing by using a single AAV to co-deliver SaCas9 and an optimal Nrl-sg2 into the mouse retina. Excitingly, in vivo inactivation of Nrl improved photoreceptor cell survival and rescued retinal function in treated Pde6a deficient mice. Thus, we showed that a practical, gene-independent method, AAV-SaCas9-mediated Nrl inactivation, holds promise for future therapeutic applications in patients with RP.

LMAN1 serves as a cargo receptor for thrombopoietin.

Thrombopoietin (TPO) is a plasma glycoprotein that binds its receptor on megakaryocytes (MK) and MK progenitors, resulting in enhanced platelet production. The mechanism by which TPO is secreted from hepatocytes remains poorly understood. LMAN1 and MCFD2 form a complex at the endoplasmic reticulum membrane, recruiting cargo proteins into COPII vesicles for secretion. In this study, we showed that LMAN1 deficient mice (with complete germline LMAN1 deficiency) exhibited mild thrombocytopenia, whereas the platelet count was entirely normal in mice with approximately 7% Lman1 expression. Surprisingly, mice deleted for Mcfd2 did not exhibit thrombocytopenia. Analysis of peripheral blood from LMAN1 deficient mice demonstrated normal platelet size and normal morphology of dense and alpha granules. LMAN1 deficient mice exhibited a trend toward reduced MK and MK progenitors in the bone marrow. We next showed that hepatocyte-specific but not hematopoietic Lman1 deletion results in thrombocytopenia, with plasma TPO level reduced in LMAN1 deficient mice, despite normal Tpo mRNA levels in LMAN1 deficient livers. TPO and LMAN1 interacted by co-immunoprecipitation in a heterologous cell line and TPO accumulated intracellularly in LMAN1 deleted cells. Altogether, these studies confirmed the hepatocyte as the cell of origin for TPO production in vivo and were consistent with LMAN1 as the endoplasmic reticulum cargo receptor that mediates the efficient secretion of TPO. To our knowledge, TPO is the first example of an LMAN1-dependent cargo that is independent of MCFD2.

Teriparatide administration is osteoanabolic but does not impact atherosclerotic plaque calcification and progression in a mouse model of menopause

Menopause exacerbates osteoporosis and increases the risk of atherosclerotic plaque rupture, leading to cardiovascular mortality. Osteoporotic women are increasingly treated with teriparatide (TPTD, 1–34 parathyroid hormone), one of the few treatments that stimulate bone formation. Despite the fact that atherosclerotic plaque calcification is a hallmark of plaque development, the impact of TPTD administration on plaque calcification remain unclear. In this context, we sought to determine the effects of TPTD administration on atherosclerosis in ovariectomized (OVX) apolipoprotein E deficient mice (ApoE−/−), as a model of postmenopausal osteoporosis. OVX ApoE−/− mice, fed a high fat, high cholesterol diet to induce atherosclerosis, received either vehicle or TPTD daily injections (40 μg/kg/d) for 4 or 10 weeks, at which points plaques are respectively weakly and heavily calcified. After sacrifice, bone remodeling was evaluated by serum markers and bone histomorphometry. Bone architectural parameters were measured by μCT. Aortic plaques were analyzed histologically, and their calcification with von Kossa staining and the calcium tracer Osteosense. Plaque inflammation and calcification markers were measured by RT-qPCR. Intermittent TPTD increased bone volume in OVX mice, due to a higher stimulation of bone formation relatively to bone resorption. These effects were not accompanied by changes in serum levels of cholesterol, triglycerides, glucose or insulin. TPTD neither significantly affected aortic plaque size, inflammation, and calcification, even if it slightly increased vascular smooth muscle cell transdifferentiation into calcifying cells. In conclusion, TPTD exhibits osteoanabolic effects in OVX ApoE−/− mice, without significantly influencing atherosclerotic plaque progression or calcification in the short term.

Comparative time-series analyses of gut microbiome profiles in genetically and chemically induced lupus-prone mice and the impacts of fecal transplantation

Although the association between gut dysbiosis (imbalance of the microbiota) in systemic lupus erythematosus (SLE) is well-known, the simultaneous exploration in gut dysbiosis in fecal and different intestinal sections before and after lupus onset (at 2, 4, 6, 8, and 10 months old) resulting from the loss of inhibitory Fc gamma receptor IIb (FcGIIb) and pristane induction have never been conducted. Anti-dsDNA (an important lupus autoantibody) and proteinuria developed as early as 6 months old in both models, with higher levels in FcGRIIb deficient (FcGRIIb-/-) mice. Compared to the healthy control at 2 and 4 months, the lupus mice (both FcGRRIIb-/- and pristane) and healthy mice at 6 months old demonstrated an alteration as indicated by the Shannon alpha diversity index, highlighting influences of lupus- and age-induced dysbiosis, respectively. Non-metric multidimensional scaling (NMDS) revealed that the fecal microbiota of FcGRIIb-/- mice were distinct from the age-matched healthy control at all timepoints (at 6 month, p < 0.05), while pristane mice showed divergence at only some timepoints. Analyses of different intestinal sections revealed similarity among microbiota in the cecum, colon, and feces, contrasting with those in the small intestines (duodenum, jejunum, and ileum). Subtle differences were found between FcGRIIb-/- and pristane mice in feces and the intestinal sections as assessed by several analyses, for examples, the similar or dissimilar distances (NMDS), the neighbor-joining clustering, and the potential metabolisms (KEGG pathway analysis). Due to the differences between the gut microbiota (feces and intestinal sections) in the lupus mice and the healthy control, rebalancing of the microbiota using rectal administration of feces from the healthy control (fecal transplantation; FMT) to 7-month-old FcGIIb-/- mice (the established lupus; positive anti-dsDNA and proteinuria) was performed. In comparison to FcGRIIb-/- mice without FMT, FMT mice (more effect on the female than the male mice) showed the lower anti-dsDNA levels with similar fecal microbiome diversity (16s DNA gene copy number) and microbiota patterns to the healthy control. In conclusion, gut microbiota (feces and intestinal sections) of lupus mice (FcGRIIb-/- and pristane) diverged from the control as early as 4–6 months old, correlating with lupus characteristics (anti-dsDNA and proteinuria). The different gut microbiota in FcGRIIb-/- and pristane suggested a possible different gut microbiota in lupus with various molecular causes. Furthermore, FMT appeared to mitigate gut dysbiosis and reduce anti-dsDNA, supporting the benefit of the rebalancing gut microbiota in lupus, with more studies are warranted.

The Parkinson's disease DJ-1/PARK7 gene controls peripheral neuronal excitability and painful neuropathy.

Parkinson's disease is a progressive neurodegenerative disease with well-documented motor symptoms as well as less recognised, but significant, non-motor symptoms. These non-motor symptoms include prodromal pain and peripheral neuropathy, the causes of which are unknown. We investigated the role of DJ-1/PARK7, a Parkinson's disease-associated gene, in prodromal pain and peripheral neuropathy. Using DJ-1 deficient mice, we conducted comprehensive sensory tests, cutaneous staining, molecular analyses and electrophysiological studies on mouse and human primary sensory neurons from dorsal root ganglia. We found that these mice exhibited cold hypersensitivity, oxidative stress, and neuropathy of the cutaneous fibres of primary sensory neurones before any motor impairments were observed. Mechanistically, DJ-1 in primary sensory neurones regulated this hypersensitivity and neuropathy via TRPA1 signalling. Interestingly, we discovered that DJ-1 also plays a role in the progression of chemotherapy-induced peripheral neuropathies. Pain and mechanisms associated with these neuropathies were exacerbated in DJ-1 deficient mice but were significantly reduced by the pharmacological activation of DJ-1. Importantly, we also confirmed the expression of DJ-1 and its therapeutic potential in human primary sensory neurons. Thus, we uncover a peripheral mechanism of DJ-1 and propose that it may serve as a new target for developing therapeutic approaches for Parkinson's disease-linked and other painful neuropathies.

The role of S-nitrosoglutathione reductase (GSNOR) in T cell-mediated immunopathology of experimental autoimmune encephalomyelitis (EAE)

Previously, we reported that both S-nitrosoglutathione (GSNO), a carrier of cellular nitric oxide, and N6022, an injectable form of GSNO reductase (GSNOR) inhibitor that increases endogenous GSNO levels, alleviate experimental autoimmune encephalomyelitis (EAE) in mice by suppressing Th1 and Th17 immune responses. Building on these findings, we explored the role of GSNOR in EAE pathogenesis and evaluated the efficacy of an orally active GSNOR inhibitor (N91115) in treating the EAE disease. EAE mice exhibited heightened expression/activity of GSNOR in the spinal cord, and the knockout of the GSNOR gene resulted in much milder clinical manifestations of EAE, with lower degrees of demyelination and axonal loss, reduced microglial and astrocyte activations, as well as suppressed Th1 and Th17 cell responses, alongside bolstered Treg immune responses. Next, we evaluated the efficacy of N91115 against EAE immunopathology. Consistent with our findings in GSNOR deficient EAE mice, daily N91115 administration reduced clinical EAE severity, with less spinal cord demyelination and axonal loss compared to untreated EAE mice. Furthermore, N91115 treated EAE mice showed diminished Th1 and Th17 immune responses and enhanced Treg responses. This observation underscores the potential of increased GSNOR expression and activity as a risk factor exacerbating EAE immunopathology, while simultaneously highlighting its potential as a target for modifying the disease. Furthermore, the balanced immune regulation provided by orally active N91115 (IL-6/IL-17a vs. IL-10) presents a promising alternative to immunosuppressive drugs, reducing the risk of opportunistic infections.

Impairment of neuromotor development and cognition associated with histopathological and neurochemical abnormalities in the cerebral cortex and striatum of glutaryl-CoA dehydrogenase deficient mice

Impairment of neuromotor development and cognition associated with histopathological and neurochemical abnormalities in the cerebral cortex and striatum of glutaryl-CoA dehydrogenase deficient mice

FoxO1 Deficiency in M-MDSCs Exacerbates B Cell Dysfunction in Systemic Lupus Erythematosus.

Myeloid-derived suppressor cells (MDSCs) contribute to the pathogenesis of systemic lupus erythematosus (SLE), in part due to promoting the survival of plasma cells. Forkhead box protein O1 (FoxO1) expression in monocytic MDSCs (M-MDSCs) exhibits a negative correlation with the SLE Disease Activity Index (SLEDAI) score. This study aimed to investigate the hypothesis that M-MDSCs specific FoxO1 deficiency enhances aberrant B cell function in aggressive SLE. We used GEO datasets and clinical cohorts to verify the FoxO1 expression and circulating M-MDSCs clinical significance. Using Cre-LoxP technology, we generated myeloid FoxO1 deficiency mice (mFoxO1-/-) to establish murine lupus-prone models. The transcriptional stage was assessed by integrating ChIP-seq with transcriptomic analysis, luciferase reporter assay and ChIP-qPCR. Methylated RNA immunoprecipitation sequencing, RNA sequencing and CRISPR-dCas9 were used to identify m6A modification. In vitro B cell co-culture experiments, Capmatinib intragastric administration, m6A-modulated MDSCs adoptive transfer, and SLE patient sample validation were performed to determine the role of FoxO1 on M-MDSCs dysregulation during B cell autoreacted with SLE. We present evidence that low FoxO1 is predominantly expressed in M-MDSCs in both SLE patients and lupus mice, and mice with myeloid FoxO1 deficiency (mFoxO1-/-) are more prone to B cell dysfunction. Mechanically, FoxO1 inhibits Met transcription by binding to the promoter region. M-MDSCs FoxO1 deficiency blocks the Met/COX2/PGE2 secretion pathway, promoting B cell proliferation and hyperactivation. Met antagonist Capmatinib effectively mitigates lupus exacerbation. Furthermore, ALKBH5 targeting catalyzes m6A modification on FoxO1 mRNA in CDS and 3'-UTR regions. Upregulation of FoxO1 mediated by ALKBH5 overexpression in M-MDSCs improves lupus progression. Finally, these correlations were confirmed in untreated SLE patients. Our findings indicate that effective inhibition of B cells mediated by ALKBH5/FoxO1/Met axis in M-MDSCs could offer a novel therapeutic approach to manage SLE.

GDF15 Associates with, but is not Responsible for, Exercise-Induced Increases in Corticosterone and Indices of Lipid Utilization in Mice.

Growth differentiation factor 15 (GDF15) is a stress-induced cytokine that increases with exercise and is thought to increase corticosterone and lipid utilization. How post-exercise nutrient availability impacts GDF15 and the physiological role that GDF15 plays during and/or in the recovery from exercise has not been elucidated. The purpose of this investigation was to examine how post-exercise nutrient availability impacts GDF15 and to use this as a model to explore associations between GDF15, corticosterone and indices of lipid and carbohydrate metabolism. In addition, we explored the causality of these relationships using GDF15 deficient mice. Male and female C57BL/6J mice ran for 2 hours on a treadmill and were sacrificed immediately or 3 hours after exercise with or without access to a chow diet. In both sexes, circulating concentrations of GDF15, corticosterone, non-esterified fatty acids (NEFA), and beta hydroxybutyrate (BHB) were higher immediately post-exercise and remained elevated when food was withheld during the recovery period. While serum GDF15 was positively associated with corticosterone, BHB and NEFA, increases in these factors were similar in wildtype and GDF15-/- mice following exercise. The lack of a genotype effect was not explained by differences in insulin, glucagon or epinephrine after exercise. Our findings provide evidence that while GDF15 is associated with increases in corticosterone and indices of lipid utilization this is not a causal relationship.

A type VI secretion system in Burkholderia species cenocepacia and orbicola triggers distinct macrophage death pathways independent of the pyrin inflammasome.

The Burkholderia cepacia complex contains opportunistic pathogens that cause chronic infections and inflammation in the lungs of people with cystic fibrosis. Two closely related species within this complex are Burkholderia cenocepacia and the recently classified Burkholderia orbicola. B. cenocepacia and B. orbicola encode a type VI secretion system and the effector TecA, which is detected by the pyrin/caspase-1 inflammasome, and triggers macrophage inflammatory death. We previously showed that the pyrin inflammasome was dispensable for lung inflammation in mice infected with B. orbicola AU1054, indicating this species activates an alternative pathway of macrophage inflammatory death. Notably, B. cenocepacia strains J2315 and K56-2 can damage macrophage phagosomes, and K56-2 triggers activation of the caspase-11 inflammasome, which detects cytosolic lipopolysaccharide. Here, we investigated inflammatory cell death in pyrin- (Mefv-/-) or caspase-1/caspase-11- (Casp1/11-/-) deficient mouse macrophages infected with B. cenocepacia J2315 or K56-2 or B. orbicola AU1054 or PC184. Macrophage inflammatory death was measured by cleavage of gasdermin D protein, the release of cytokines IL-1α and IL-1β, and plasma membrane rupture. We found that J2315 and K56-2 are detected by the caspase-11 inflammasome in Mefv-/- macrophages, resulting in IL-1β release. By contrast, inflammasome activation was not detected in Mefv-/- macrophages infected with AU1054 or PC184. Instead, AU1054 triggered an alternative macrophage inflammatory death pathway that required TecA and resulted in plasma membrane rupture and IL-1α release. Structural modeling of TecA orthologs in B. cenocepacia and B. orbicola suggested that amino acid changes in the latter may underlie its ability to trigger a non-inflammasome macrophage death pathway.

Ethanol consumption during gestation promotes placental alterations in IGF-1 deficient mouse placentas

Background During pregnancy, the placenta is an extremely important organ as it secretes its own hormones, e.g. insulin-like growth factor 1 (IGF-1), to ensure proper intrauterine fetal growth and development. Ethanol, an addictive and widely used drug, has numerous adverse effects during pregnancy, including fetal growth restriction (FGR). To date, the molecular mechanisms by which ethanol triggers its toxic effects during pregnancy, particularly in the placenta, are not entirely known. For this reason, a murine model of partial IGF-1 deficiency was used to determine ethanol alterations in placental morphology and aspartyl/asparaginyl β-hydroxylase (AAH) expression. Methods Wild type (WT, Igf1 +/+) and heterozygous (HZ, Igf1 +/-) female mice were given 10% ethanol in water during 14 days as an acclimation period and throughout pregnancy. WT and HZ female mice given water were used as controls. At gestational day 19, pregnant dams were sacrificed, placentas were collected and genotyped for subsequent studies. Results IGF-1 deficiency and ethanol consumption during pregnancy altered placental morphology, and decreased placental efficiency and AAH expression in placentas from all genotypes. No differences were found in Igf1, Igf2, Igf1r and Igf2r mRNA expression in placentas from all groups. Conclusions IGF-1 deficiency and ethanol consumption throughout gestation altered placental development, suggesting the crucial role of IGF-1 in the establishment of an adequate intrauterine environment that allows fetal growth. However, more studies are needed to study the precise mechanism to stablish the relation between both insults.