Fatal demyelinating disease is induced by monocyte-derived macrophages in the absence of TGF-ß signaling.

The cytokine transforming growth factor-ß (TGF-ß) regulates the development and homeostasis of several tissue-resident macrophage populations, including microglia. TGF-ß is not critical for microglia survival but is required for the maintenance of the microglia-specific homeostatic gene signature1,2. Under defined host conditions, circulating monocytes can compete for the microglial niche and give rise to long-lived monocyte-derived macrophages residing in the central nervous system (CNS)3-5. Whether monocytes require TGF-ß for colonization of the microglial niche and maintenance of CNS integrity is unknown. We found that abrogation of TGF-ß signaling in CX3CR1+ monocyte-derived macrophages led to rapid onset of a progressive and fatal demyelinating motor disease characterized by myelin-laden giant macrophages throughout the spinal cord. Tgfbr2-deficient macrophages were characterized by high expression of genes encoding proteins involved in antigen presentation, inflammation and phagocytosis. TGF-ß is thus crucial for the functional integration of monocytes into the CNS microenvironment.

Neutrophils license iNKT cells to regulate self-reactive mouse B cell responses.

The innate responsiveness of the immune system is important not only for quick responses to pathogens but also for the initiation and shaping of the subsequent adaptive immune response. Activation via the cytokine IL-18, a product of inflammasomes, gives rise to a rapid response that includes the production of self-reactive antibodies. As increased concentrations of this cytokine are found in inflammatory diseases, we investigated the origin of the B cell response and its regulation. We identified an accumulation of B cell-helper neutrophils in the spleen that interacted with innate-type invariant natural killer T cells (iNKT cells) to regulate B cell responses. We found that neutrophil-dependent expression of the death-receptor ligand FasL by iNKT cells was needed to restrict autoantibody production. Neutrophils can thus license iNKT cells to regulate potentially harmful autoreactive B cell responses during inflammasome-driven inflammation.

Noncanonical PDK4 action alters mitochondrial dynamics to affect the cellular respiratory status.

Dynamic regulation of mitochondrial morphology provides cells with the flexibility required to adapt and respond to electron transport chain (ETC) toxins and mitochondrial DNA-linked disease mutations, yet the mechanisms underpinning the regulation of mitochondrial dynamics machinery by these stimuli is poorly understood. Here, we show that pyruvate dehydrogenase kinase 4 (PDK4) is genetically required for cells to undergo rapid mitochondrial fragmentation when challenged with ETC toxins. Moreover, PDK4 overexpression was sufficient to promote mitochondrial fission even in the absence of mitochondrial stress. Importantly, we observed that the PDK4-mediated regulation of mitochondrial fission was independent of its canonical function, i.e., inhibitory phosphorylation of the pyruvate dehydrogenase complex (PDC). Phosphoproteomic screen for PDK4 substrates, followed by nonphosphorylatable and phosphomimetic mutations of the PDK4 site revealed cytoplasmic GTPase, Septin 2 (SEPT2), as the key effector molecule that acts as a receptor for DRP1 in the outer mitochondrial membrane to promote mitochondrial fission. Conversely, inhibition of the PDK4-SEPT2 axis could restore the balance in mitochondrial dynamics and reinvigorates cellular respiration in mitochondrial fusion factor, mitofusin 2-deficient cells. Furthermore, PDK4-mediated mitochondrial reshaping limits mitochondrial bioenergetics and supports cancer cell growth. Our results identify the PDK4-SEPT2-DRP1 axis as a regulator of mitochondrial function at the interface between cellular bioenergetics and mitochondrial dynamics.

Bacterial peptidoglycan signalling in microglia: Activation by MDP via the NF-κB/MAPK pathway.

Bacterial peptidoglycan (PGN) fragments are commonly studied in the context of bacterial infections. However, PGN fragments recently gained recognition as signalling molecules from the commensal gut microbiota in the healthy host. Here we focus on the minimal bioactive PGN motif muramyl dipeptide (MDP), found in both Gram-positive and Gram-negative commensal bacteria, which signals through the Nod2 receptor. MDP from the gut microbiota translocates to the brain and is associated with changes in neurodevelopment and behaviour, yet there is limited knowledge about the underlying mechanisms. In this study we demonstrate that physiologically relevant doses of MDP induce rapid changes in microglial gene expression and lead to cytokine and chemokine secretion. In immortalised microglial (IMG) cells, C-C Motif Chemokine Ligand 5 (CCL5/RANTES) expression is acutely sensitive to the lowest physiologically prevalent dose (0.1 µg/ml) of MDP. As CCL5 plays an important role in memory formation and synaptic plasticity, microglial CCL5 might be the missing link in elucidating MDP-induced alterations in synaptic gene expression. We observed that a higher physiological dose of MDP elevates the expression of cytokines TNF-α and IL-1ß, indicating a transition toward a pro-inflammatory phenotype in IMG cells, which was validated in primary microglial cultures. Furthermore, MDP induces the translocation of NF-κB subunit p65 into the nucleus, which is blocked by MAPK p38 inhibitor SB202190, suggesting that an interplay of both the NF-κB and MAPK pathways is responsible for the MDP-specific microglial phenotype. These findings underscore the significance of different MDP levels in shaping microglial function in the CNS and indicate MDP as a potential mediator for early inflammatory processes in the brain. It also positions microglia as an important target in the gut microbiota-brain-axis pathway through PGN signalling.

Myeloid cell-specific topoisomerase 1 inhibition using DNA origami mitigates neuroinflammation.

Targeting myeloid cells, especially microglia, for the treatment of neuroinflammatory diseases such as multiple sclerosis (MS), is underappreciated. Our in silico drug screening reveals topoisomerase 1 (TOP1) inhibitors as promising drug candidates for microglial modulation. We show that TOP1 is highly expressed in neuroinflammatory conditions, and TOP1 inhibition using camptothecin (CPT) and its FDA-approved analog topotecan (TPT) reduces inflammatory responses in microglia/macrophages and ameliorates neuroinflammation in vivo. Transcriptomic analyses of sorted microglia from LPS-challenged mice reveal an altered transcriptional phenotype following TPT treatment. To target myeloid cells, we design a nanosystem using ß-glucan-coated DNA origami (MyloGami) loaded with TPT (TopoGami). MyloGami shows enhanced specificity to myeloid cells while preventing the degradation of the DNA origami scaffold. Myeloid-specific TOP1 inhibition using TopoGami significantly suppresses the inflammatory response in microglia and mitigates MS-like disease progression. Our findings suggest that TOP1 inhibition in myeloid cells represents a therapeutic strategy for neuroinflammatory diseases and that the myeloid-specific nanosystems we designed may also benefit the treatment of other diseases with dysfunctional myeloid cells.

Inhibition of pyruvate dehydrogenase kinase 4 ameliorates kidney ischemia-reperfusion injury by reducing succinate accumulation during ischemia and preserving mitochondrial function during reperfusion.

Ischemia-reperfusion (IR) injury, a leading cause of acute kidney injury (AKI), is still without effective therapies. Succinate accumulation during ischemia followed by its oxidation during reperfusion leads to excessive reactive oxygen species (ROS) and severe kidney damage. Consequently, the targeting of succinate accumulation may represent a rational approach to the prevention of IR-induced kidney injury. Since ROS are generated primarily in mitochondria, which are abundant in the proximal tubule of the kidney, we explored the role of pyruvate dehydrogenase kinase 4 (PDK4), a mitochondrial enzyme, in IR-induced kidney injury using proximal tubule cell-specific Pdk4 knockout (Pdk4ptKO) mice. Knockout or pharmacological inhibition of PDK4 ameliorated IR-induced kidney damage. Succinate accumulation during ischemia, which is responsible for mitochondrial ROS production during reperfusion, was reduced by PDK4 inhibition. PDK4 deficiency established conditions prior to ischemia resulting in less succinate accumulation, possibly because of a reduction in electron flow reversal in complex II, which provides electrons for the reduction of fumarate to succinate by succinate dehydrogenase during ischemia. The administration of dimethyl succinate, a cell-permeable form of succinate, attenuated the beneficial effects of PDK4 deficiency, suggesting that the kidney-protective effect is succinate-dependent. Finally, genetic or pharmacological inhibition of PDK4 prevented IR-induced mitochondrial damage in mice and normalized mitochondrial function in an in vitro model of IR injury. Thus, inhibition of PDK4 represents a novel means of preventing IR-induced kidney injury, and involves the inhibition of ROS-induced kidney toxicity through reduction in succinate accumulation and mitochondrial dysfunction.

Activation of TRPV1 receptor facilitates myelin repair following demyelination via the regulation of microglial function.

The transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel that is activated by capsaicin (CAP), the main component of chili pepper. Despite studies in several neurological diseases, the role of TRPV1 in demyelinating diseases remains unknown. Herein, we reported that TRPV1 expression was increased within the corpus callosum during demyelination in a cuprizone (CPZ)-induced demyelination mouse model. TRPV1 deficiency exacerbated motor coordinative dysfunction and demyelination in CPZ-treated mice, whereas the TRPV1 agonist CAP improved the behavioral performance and facilitated remyelination. TRPV1 was predominantly expressed in Iba1+ microglia/macrophages in human brain sections of multiple sclerosis patients and mouse corpus callosum under demyelinating conditions. TRPV1 deficiency decreased microglial recruitment to the corpus callosum, with an associated increase in the accumulation of myelin debris. Conversely, the activation of TRPV1 by CAP enhanced the recruitment of microglia to the corpus callosum and potentiated myelin debris clearance. Using real-time live imaging we confirmed an increased phagocytic function of microglia following CAP treatment. In addition, the expression of the scavenger receptor CD36 was increased, and that of the glycolysis regulators Hif1a and Hk2 was decreased. We conclude that TRPV1 is an important regulator of microglial function in the context of demyelination and may serve as a promising therapeutic target for demyelinating diseases such as multiple sclerosis.

Inhibition of colony stimulating factor-1 receptor (CSF-1R) as a potential therapeutic strategy for neurodegenerative diseases: opportunities and challenges.

Microglia are specialized dynamic immune cells in the central nervous system (CNS) that plays a crucial role in brain homeostasis and in disease states. Persistent neuroinflammation is considered a hallmark of many neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) and primary progressive multiple sclerosis (MS). Colony stimulating factor 1-receptor (CSF-1R) is predominantly expressed on microglia and its expression is significantly increased in neurodegenerative diseases. Cumulative findings have indicated that CSF-1R inhibitors can have beneficial effects in preclinical neurodegenerative disease models. Research using CSF-1R inhibitors has now been extended into non-human primates and humans. This review article summarizes the most recent advances using CSF-1R inhibitors in different neurodegenerative conditions including AD, PD, HD, ALS and MS. Potential challenges for translating these findings into clinical practice are presented.

Spinal Cord Injury Induces Permanent Reprogramming of Microglia into a Disease-Associated State Which Contributes to Functional Recovery.

Microglia are resident myeloid cells of the CNS. Recently, single-cell RNA sequencing (scRNAseq) has enabled description of a disease-associated microglia (DAM) with a role in neurodegeneration and demyelination. In this study, we use scRNAseq to investigate the temporal dynamics of immune cells harvested from the epicenter of traumatic spinal cord injury (SCI) induced in female mice. We find that as a consequence of SCI, baseline microglia undergo permanent transcriptional reprogramming into a previously uncharacterized subtype of microglia with striking similarities to previously reported DAM as well as a distinct microglial state found during development. Using a microglia depletion model we showed that DAM in SCI are derived from baseline microglia and strongly enhance recovery of hindlimb locomotor function following injury.SIGNIFICANCE STATEMENT Although disease-associated microglia (DAM) have been the subject of strong research interest during recent years (Keren-Shaul, 2017; Jordão, 2019), their cellular origin and their role in "normal" acute injury processes is not well understood. Our work directly addresses the origin and the role of DAM in traumatic injury response. Further, we use a microglia depletion model to prove that DAM in spinal cord injury (SCI) are indeed derived from homeostatic microglia, and that they strongly enhance recovery. Thus, in this work we significantly expand the knowledge of immune response to traumatic injury, demonstrate the applicability to human injury via our unique access to injured human spinal cord tissue, and provide the community with a comprehensive dataset for further exploration.

An overlooked subset of Cx3cr1wt/wt microglia in the Cx3cr1CreER-Eyfp/wt mouse has a repopulation advantage over Cx3cr1CreER-Eyfp/wt microglia following microglial depletion.

BACKGROUND: Fluorescent reporter labeling and promoter-driven Cre-recombinant technologies have facilitated cellular investigations of physiological and pathological processes, including the widespread use of the Cx3cr1CreER-Eyfp/wt mouse strain for studies of microglia. METHODS: Immunohistochemistry, Flow Cytometry, RNA sequencing and whole-genome sequencing were used to identify the subpopulation of microglia in Cx3cr1CreER-Eyfp/wt mouse brains. Genetically mediated microglia depletion using Cx3cr1CreER-Eyfp/wtRosa26DTA/wt mice and CSF1 receptor inhibitor PLX3397 were used to deplete microglia. Primary microglia proliferation and migration assay were used for in vitro studies. RESULTS: We unexpectedly identified a subpopulation of microglia devoid of genetic modification, exhibiting higher Cx3cr1 and CX3CR1 expression than Cx3cr1CreER-Eyfp/wtCre+Eyfp+ microglia in Cx3cr1CreER-Eyfp/wt mouse brains, thus termed Cx3cr1highCre-Eyfp- microglia. This subpopulation constituted less than 1% of all microglia under homeostatic conditions, but after Cre-driven DTA-mediated microglial depletion, Cx3cr1highCre-Eyfp- microglia escaped depletion and proliferated extensively, eventually occupying one-third of the total microglial pool. We further demonstrated that the Cx3cr1highCre-Eyfp- microglia had lost their genetic heterozygosity and become homozygous for wild-type Cx3cr1. Therefore, Cx3cr1highCre-Eyfp- microglia are Cx3cr1wt/wtCre-Eyfp-. Finally, we demonstrated that CX3CL1-CX3CR1 signaling regulates microglial repopulation both in vivo and in vitro. CONCLUSIONS: Our results raise a cautionary note regarding the use of Cx3cr1CreER-Eyfp/wt mouse strains, particularly when interpreting the results of fate mapping, and microglial depletion and repopulation studies.

A Two-to-Five Year Follow-Up of a Pediatric Acute-Onset Neuropsychiatric Syndrome Cohort.

Little is known about the long-term prognosis of children with pediatric acute-onset neuropsychiatric syndrome (PANS). Out of the 46 eligible patients from the Karolinska PANS cohort, 34 consented to participate in a follow-up (median 3.3 years). Participants underwent a thorough clinical evaluation and were classified according to their clinical course. Resulting groups were compared on clinical characteristics and laboratory test results. We observed significant reductions in clinician-rated PANS symptom severity and improved general function. Two patients were classified as remitted, 20 as relapsing-remitting, and 12 as having a chronic-static/progressive course. The latter group had an earlier onset, greater impairment and received more pharmacological and psychological treatments. Although remission was rare, the majority of children with PANS were significantly improved over the follow-up period but a non-negligible minority of patients displayed a chronic-static/progressive course and required additional treatments. The proposed definitions of flare and clinical course may be useful in future clinical trials.

Uncovering sex differences of rodent microglia.

There are inherent structural and functional differences in the central nervous systems (CNS) of females and males. It has been gradually established that these sex-specific differences are due to a spectrum of genetic, epigenetic, and hormonal factors which actively contribute to the differential incidences, disease courses, and even outcomes of CNS diseases between sexes. Microglia, as principle resident macrophages in the CNS, play a crucial role in both CNS physiology and pathology. However, sex differences of microglia have been relatively unexplored until recently. Emerging data has convincingly demonstrated the existence of sex-dependent structural and functional differences of rodent microglia, consequently changing our current understanding of these versatile cells. In this review, we attempt to comprehensively outline the current advances revealing microglial sex differences in rodent and their potential implications for specific CNS diseases with a stark sex difference. A detailed understanding of molecular processes underlying microglial sex differences is of major importance in design of translational sex- and microglia-specific therapeutic approaches.

Metabolic activation of CaMKII by coenzyme A.

Active metabolism regulates oocyte cell death via calcium/calmodulin-dependent protein kinase II (CaMKII)-mediated phosphorylation of caspase-2, but the link between metabolic activity and CaMKII is poorly understood. Here we identify coenzyme A (CoA) as the key metabolic signal that inhibits Xenopus laevis oocyte apoptosis by directly activating CaMKII. We found that CoA directly binds to the CaMKII regulatory domain in the absence of Ca(2+) to activate CaMKII in a calmodulin-dependent manner. Furthermore, we show that CoA inhibits apoptosis not only in X. laevis oocytes but also in Murine oocytes. These findings uncover a direct mechanism of CaMKII regulation by metabolism and further highlight the importance of metabolism in preserving oocyte viability.

Safety and target engagement profile of two oxaloacetate doses in Alzheimer's patients.

INTRODUCTION: Brain bioenergetics are defective in Alzheimer's disease (AD). Preclinical studies find oxaloacetate (OAA) enhances bioenergetics, but human safety and target engagement data are lacking. METHODS: We orally administered 500 or 1000 mg OAA, twice daily for 1 month, to AD participants (n = 15 each group) and monitored safety and tolerability. To assess brain metabolism engagement, we performed fluorodeoxyglucose positron emission tomography (FDG PET) and magnetic resonance spectroscopy before and after the intervention. We also assessed pharmacokinetics and cognitive performance. RESULTS: Both doses were safe and tolerated. Compared to the lower dose, the higher dose benefited FDG PET glucose uptake across multiple brain regions (P < .05), and the higher dose increased parietal and frontoparietal glutathione (P < .05). We did not demonstrate consistent blood level changes and cognitive scores did not improve. CONCLUSIONS: 1000 mg OAA, taken twice daily for 1 month, is safe in AD patients and engages brain energy metabolism.

Absence of microglia or presence of peripherally-derived macrophages does not affect tau pathology in young or old hTau mice.

Microglia are implicated in the pathophysiology of several neurodegenerative disorders, including Alzheimer's disease. While the role of microglia and peripheral macrophages in regulating amyloid beta pathology has been well characterized, the impact of these distinct cell subsets on tau pathology remains poorly understood. We and others have recently demonstrated that monocytes can engraft the brain and give rise to long-lived parenchymal macrophages, even under nonpathological conditions. We undertook the current study to investigate the regulation of tau pathology by microglia and peripheral macrophages using hTau transgenic mice, which do not exhibit microglial activation/pathology or macrophage engraftment. To assess the direct impact of microglia on tau pathology we developed a protocol for long-term microglial depletion in Cx3cr1CreER R26DTA mice and crossed them with hTau mice. We then depleted microglia up to 3 months in both young and old mice, but no net change in forebrain soluble oligomeric tau or total or phosphorylated levels of aggregated tau was recorded. To investigate the consequence of peripherally-derived parenchymal macrophages on tau aggregation we partially repopulated the hTau microglial pool with peripheral macrophages, but this also did not affect levels of tau oligomers or insoluble aggregates. Our study questions the direct involvement of microglia or peripheral macrophages in the development of tau pathology in the hTau model.

Aggravated brain injury after neonatal hypoxic ischemia in microglia-depleted mice.

BACKGROUND: Neuroinflammation plays an important role in neonatal hypoxic-ischemic encephalopathy (HIE). Although microglia are largely responsible for injury-induced inflammatory response, they play beneficial roles in both normal and disease states. However, the effects of microglial depletion on neonatal HIE remain unclear. METHODS: Tamoxifen was administered to Cx3cr1CreER/+Rosa26DTA/+ (microglia-depleted model) and Cx3cr1CreER/+Rosa26DTA/- (control) mice at P8 and P9 to assess the effect of microglial depletion. The density of microglia was quantified using Iba-1 staining. Moreover, the proportion of resident microglia after the HI insult was analyzed using flow cytometric analysis. At P10, the HI insult was conducted using the Rice-Vannucci procedure at P10. The infarct size and apoptotic cells were analyzed at P13. Cytokine analyses were performed using quantitative polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) at P13. RESULTS: At P10, tamoxifen administration induced > 99% microglial depletion in DTA+ mice. Following HI insult, there was persisted microglial depletion over 97% at P13. Compared to male DTA- mice, male DTA+ mice exhibited significantly larger infarct volumes; however, there were no significant differences among females. Moreover, compared to male DTA- mice, male DTA+ mice had a significantly higher density of TUNEL+ cells in the caudoputamen, cerebral cortex, and thalamus. Moreover, compared to female DTA- mice, female DTA+ mice showed a significantly greater number of TUNEL+ cells in the hippocampus and thalamus. Compared to DTA- mice, ELISA revealed significantly lower IL-10 and TGF-ß levels in both male and female DTA+ mice under both normal conditions and after HI (more pronounced). CONCLUSION: We established a microglial depletion model that aggravated neuronal damage and apoptosis after the HI insult, which was predominantly observed in males.

PDK4 drives metabolic alterations and muscle atrophy in cancer cachexia.

Cachexia is frequently accompanied by severe metabolic derangements, although the mechanisms responsible for this debilitating condition remain unclear. Pyruvate dehydrogenase kinase (PDK)4, a critical regulator of cellular energetic metabolism, was found elevated in experimental models of cancer, starvation, diabetes, and sepsis. Here we aimed to investigate the link between PDK4 and the changes in muscle size in cancer cachexia. High PDK4 and abnormal energetic metabolism were found in the skeletal muscle of colon-26 tumor hosts, as well as in mice fed a diet enriched in Pirinixic acid, previously shown to increase PDK4 levels. Viral-mediated PDK4 overexpression in myotube cultures was sufficient to promote myofiber shrinkage, consistent with enhanced protein catabolism and mitochondrial abnormalities. On the contrary, blockade of PDK4 was sufficient to restore myotube size in C2C12 cultures exposed to tumor media. Our data support, for the first time, a direct role for PDK4 in promoting cancer-associated muscle metabolic alterations and skeletal muscle atrophy.-Pin, F., Novinger, L. J., Huot, J. R., Harris, R. A., Couch, M. E., O'Connell, T. M., Bonetto, A. PDK4 drives metabolic alterations and muscle atrophy in cancer cachexia.

E2F1 Suppresses Oxidative Metabolism and Endothelial Differentiation of Bone Marrow Progenitor Cells.

RATIONALE: The majority of current cardiovascular cell therapy trials use bone marrow progenitor cells (BM PCs) and achieve only modest efficacy; the limited potential of these cells to differentiate into endothelial-lineage cells is one of the major barriers to the success of this promising therapy. We have previously reported that the E2F transcription factor 1 (E2F1) is a repressor of revascularization after ischemic injury. OBJECTIVE: We sought to define the role of E2F1 in the regulation of BM PC function. METHODS AND RESULTS: Ablation of E2F1 (E2F1 deficient) in mouse BM PCs increases oxidative metabolism and reduces lactate production, resulting in enhanced endothelial differentiation. The metabolic switch in E2F1-deficient BM PCs is mediated by a reduction in the expression of pyruvate dehydrogenase kinase 4 and pyruvate dehydrogenase kinase 2; overexpression of pyruvate dehydrogenase kinase 4 reverses the enhancement of oxidative metabolism and endothelial differentiation. Deletion of E2F1 in the BM increases the amount of PC-derived endothelial cells in the ischemic myocardium, enhances vascular growth, reduces infarct size, and improves cardiac function after myocardial infarction. CONCLUSION: Our results suggest a novel mechanism by which E2F1 mediates the metabolic control of BM PC differentiation, and strategies that inhibit E2F1 or enhance oxidative metabolism in BM PCs may improve the effectiveness of cell therapy.

Induction of SIRT1 by melatonin improves alcohol-mediated oxidative liver injury by disrupting the CRBN-YY1-CYP2E1 signaling pathway.

Alcoholic liver disease is the most prevalent chronic liver disease. Melatonin is known to control many vital processes. Here, we explored a novel molecular mechanism by which melatonin-induced SIRT1 signaling protects against alcohol-mediated oxidative stress and liver injury. Gene expression profiles and metabolic changes were measured in liver specimens of mice and human subjects. Expression levels of Cb1r, Crbn, Btg2, Yy1, pro-inflammatory cytokines, and Cyp2e1 were significantly enhanced in chronic alcohol-challenged mice and human subjects. Levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hepatic CYP2E1 protein, and reactive oxygen species (ROS) were elevated in alcohol-fed WT mice but not in Cb1r antagonist-treated, Crbn null, or Yy1-silenced mice. Importantly, alcohol-induced Yy1 and Cyp2e1 expression, ROS amount, and liver injury were markedly diminished by melatonin treatment and the transduction of Sirt1 in mice, whereas this phenomenon was prominently ablated by silencing of Sirt1. Notably, SIRT1 physically interacted with YY1 and attenuated YY1 occupancy on the Cyp2e1 gene promoter. Melatonin-SIRT1 signaling ameliorates alcohol-induced oxidative liver injury by disrupting the CRBN-YY1-CYP2E1 signaling pathway. The manipulation of CRBN-YY1-CYP2E1 signaling network by the melatonin-SIRT1 pathway highlights a novel entry point for treating alcoholic liver disease.

Features of repeated muscle biopsies and phenotypes of monocytes in paired blood samples and clinical long-term response to treatment in patients with idiopathic inflammatory myopathy: a pilot study.

OBJECTIVES: In a pilot study we aimed to identify biomarkers in repeated muscle biopsies and paired blood samples, taken before and after conventional immunosuppressive therapy, in order to predict long-term therapeutic response in patients with idiopathic inflammatory myopathies (IIM). METHODS: Muscle biopsies were selected from 13 new onset patients, six responders and seven non-responders. Repeated muscle biopsies after a median of 11 months follow-up were available from 9 patients and paired peripheral blood mononuclear cells (PBMCs) from 5 patients. Treatment response after 3 years was defined by MMT-8 measuring muscle strength and the ACR/EULAR 2016 improvement criteria. Frozen biopsy sections were immunohistochemically stained for expression of CD3, CD66b, IL-15, CD68, CD163 and myosin heavy chain neonatal (MHCn). PBMCs were analysed by flow cytometry for monocyte phenotypes (CD14, CD16, CD68, CX3CR1, and CCR2). RESULTS: Before treatment there were no significant differences in any clinical or muscle biopsy variables or monocyte subsets between responders and non-responders. MMT-8 was significantly higher compared to baseline in the responders at 3-year follow-up. In responders the expression of CD68 in the repeated biopsies was significantly lower compared to non-responders (p<0.05). CONCLUSIONS: Baseline biopsy, monocyte profile or clinical data did not predict long-term treatment response, but in the repeated biopsy within 1 year of immunosuppressive treatment, the lower number of macrophages (CD68+) seemed to predict a more favourable long-term clinical response with regard to improved muscle strength.