Abstract 472: Liver X Receptor Ligands Suppress Intestinal Soat2 and Reduce Cholesterol in Mice Fed a High Cholesterol Diet

The nuclear receptors, liver X receptor-alpha and -beta (LXRa and LXRb), were originally identified as orphan members of the nuclear receptor (NR) superfamily that function as heterodimers with the retinoid X receptor (RXR). Both LXRa and LXRb play important roles in cholesterol homeostasis and lipid metabolism and have been implicated in the pathology of several diseases including atherosclerosis, cancer, and obesity. Detailed examination of mice deficient in LXRa have revealed significant information regarding its role in regulating lipid metabolism while pharmacological roles of LXR in metabolism and inflammation have been identified using synthetic agonists. We have identified novel synthetic LXR Inverse Agonists that display the ability to suppress lipogenesis and significantly improve the phenotype of fatty liver diseases in several mouse models. During our previous investigation of LXR inverse agonists and fatty liver, we observed a substantial decrease in LDL and total cholesterol, as well as a significant decrease in soat2 gene expression. Recent basic and clinical studies indicate that soat2 may be a potential therapeutic target for cholesterol regulation and atherosclerosis treatment. Based on our observations, we investigated the effects of tissue-selective LXR inverse agonists on cholesterol regulation with greater intensity. We hypothesized that soat2 may be a novel target of LXR and that selectively suppressing LXR in the liver and/or intestine may lead to lowered cholesterol levels in hyperlipidemic models (n = 12). While our research is currently ongoing, we have validated soat2 as a potential LXR target gene by ChIP in hepatocytes, RNA-Seq experiments, fecal cholesterol excretion experiments, as well as expression assays in LXRa/b double knockout mouse tissues (n = 3). Additional studies in LDLr KO mice indicate that selectively targeting LXR in the gut with inverse agonists significantly decrease total and LDL cholesterol (n=12). We believe that this is an innovative method of targeting hypercholesterolemia and may lead to a new class of atherosclerosis therapeutics.

Circadian rhythm-dependent and circadian rhythm-independent impacts of the molecular clock on type 3 innate lymphoid cells

Many gut functions are attuned to circadian rhythm. Intestinal group 3 innate lymphoid cells (ILC3s) include NKp46⁺ and NKp46^- subsets, which are RORγt dependent and provide mucosal defense through secretion of interleukin-22 (IL-22) and IL-17. Because ILC3s highly express some key circadian clock genes, we investigated whether ILC3s are also attuned to circadian rhythm. We noted circadian oscillations in the expression of clock and cytokine genes, such as REV-ERBα, IL-22, and IL-17, whereas acute disruption of the circadian rhythm affected cytokine secretion by ILC3s. Because of prominent and rhythmic expression of REV-ERBα in ILC3s, we also investigated the impact of constitutive deletion of REV-ERBα, which has been previously shown to inhibit the expression of a RORγt repressor, NFIL3, while also directly antagonizing DNA binding of RORγt. Development of the NKp46⁺ ILC3 subset was markedly impaired, with reduced cell numbers, RORγt expression, and IL-22 production in REV-ERBα-deficient mice. The NKp46^- ILC3 subsets developed normally, potentially due to compensatory expression of other clock genes, but IL-17 secretion paradoxically increased, probably because RORγt was not antagonized by REV-ERBα. We conclude that ILC3s are attuned to circadian rhythm, but clock regulator REV-ERBα also has circadian-independent impacts on ILC3 development and functions due to its roles in the regulation of RORγt.

SR9009 administered for one day after myocardial ischemia-reperfusion prevents heart failure in mice by targeting the cardiac inflammasome

Reperfusion of patients after myocardial infarction (heart attack) triggers cardiac inflammation that leads to infarct expansion and heart failure (HF). We previously showed that the circadian mechanism is a critical regulator of reperfusion injury. However, whether pharmacological targeting using circadian medicine limits reperfusion injury and protects against HF is unknown. Here, we show that short-term targeting of the circadian driver REV-ERB with SR9009 benefits long-term cardiac repair post-myocardial ischemia reperfusion in mice. Gain and loss of function studies demonstrate specificity of targeting REV-ERB in mice. Treatment for just one day abates the cardiac NLRP3 inflammasome, decreasing immunocyte recruitment, and thereby allowing the vulnerable infarct to heal. Therapy is given in vivo, after reperfusion, and promotes efficient repair. This study presents downregulation of the cardiac inflammasome in fibroblasts as a cellular target of SR9009, inviting more targeted therapeutic investigations in the future.

A synthesis strategy for tetracyclic terpenoids leads to agonists of ERβ

Natural product and natural product-like molecules continue to be important for the development of pharmaceutical agents, as molecules in this class play a vital role in the pipeline for new therapeutics. Among these, tetracyclic terpenoids are privileged, with >100 being FDA-approved drugs. Despite this significant pharmaceutical success, there remain considerable limitations to broad medicinal exploitation of the class due to lingering scientific challenges associated with compound availability. Here, we report a concise asymmetric route to forging natural and unnatural (enantiomeric) C19 and C20 tetracyclic terpenoid skeletons suitable to drive medicinal exploration. While efforts have been focused on establishing the chemical science, early investigations reveal that the emerging chemical technology can deliver compositions of matter that are potent and selective agonists of the estrogen receptor beta, and that are selectively cytotoxic in two different glioblastoma cell lines (U251 and U87).

Many natural-product like drugs have a tetracyclic terpenoid core. Here, the authors developed a synthesis of triterpene-like tetracyclic systems, and apply this method to the preparation of a number of enantiomeric compounds, two of which are very selective ligands for estrogen receptor beta

Pharmacological activation of the nuclear receptor REV-ERB reverses cognitive deficits and reduces amyloid-β burden in a mouse model of Alzheimer's disease

Alzheimer's disease currently lacks treatment options that effectively reverse the biological/anatomical pathology and cognitive deficits associated with the disease. Loss of function of the nuclear receptor REV-ERB is associated with reduced cognitive function in mouse models. The effect of enhanced REV-ERB activity on cognitive function has not been examined. In this study, we tested the hypothesis that enhanced REV-ERB function may enhance cognitive function in a model of Alzheimer's disease. We utilized the REV-ERB agonist SR9009 to pharmacologically activate the activity of REV-ERB in the SAMP8 mouse model of Alzheimer's disease. SR9009 reversed cognitive dysfunction of an aged SAMP8 mouse in several behavioral assays including novel object recognition, T-maze foot shock avoidance, and lever press operant conditioning task assessments. SR9009 treatment reduced amyloid-β 1-40 and 1-42 levels in the cortex, which is consistent with improved cognitive function. Furthermore, SR9009 treatment led to increased hippocampal PSD-95, cortical synaptophysin expression and the number of synapses suggesting improvement in synaptic function. We conclude that REV-ERB is a potential target for treatment of Alzheimer's disease.

Doubled lifespan and patient-like pathologies in progeria mice fed high-fat diet

Hutchinson-Gilford Progeria Syndrome (HGPS) is a devastating premature aging disease. Mouse models have been instrumental for understanding HGPS mechanisms and for testing therapies, which to date have had only marginal benefits in mice and patients. Barriers to developing effective therapies include the unknown etiology of progeria mice early death, seemingly unrelated to the reported atherosclerosis contributing to HGPS patient mortality, and mice not recapitulating the severity of human disease. Here, we show that progeria mice die from starvation and cachexia. Switching progeria mice approaching death from regular diet to high-fat diet (HFD) rescues early lethality and ameliorates morbidity. Critically, feeding the mice only HFD delays aging and nearly doubles lifespan, which is the greatest lifespan extension recorded in progeria mice. The extended lifespan allows for progeria mice to develop degenerative aging pathologies of a severity that emulates the human disease. We propose that starvation and cachexia greatly influence progeria phenotypes and that nutritional/nutraceutical strategies might help modulate disease progression. Importantly, progeria mice on HFD provide a more clinically relevant animal model to study mechanisms of HGPS pathology and to test therapies.

RORγ regulates the NLRP3 inflammasome

RAR-related orphan receptor γ (RORγ) is a nuclear receptor that plays an essential role in the development of T helper 17 (T_h17) cells of the adaptive immune system. The NLRP3 inflammasome is a component of the innate immune system that processes interleukin (IL)-1β into a mature cytokine. Elevated activity of the NLRP3 inflammasome contributes to the progression of an array of inflammatory diseases. Bone marrow-derived macrophages (BMDMs) isolated from RORγ-null mice displayed reduced capacity to secrete IL-1β, and they also displayed a reduction in Nlrp3 and Il1b gene expression. Examination of the promoters of the Il1b and Nlrp3 genes revealed multiple putative ROR response elements (ROREs) that were occupied by RORγ. RORγ inverse agonists were effective inhibitors of the inflammasome. RORγ inverse agonists suppressed lipopolysaccharide (LPS)/ATP-stimulated IL-1β secretion and expression of Il1b and Nlrp3 in BMDMs. Additionally, the ability of the RORγ inverse agonists to suppress IL-1β secretion was lost in Nlrp3-null macrophages. The potential for targeting the NLRP3 inflammasome in vivo using RORγ inverse agonists was examined in two models: LPS-induced sepsis and fulminant hepatitis. Pharmacological inhibition of RORγ activity reduced plasma IL-1β as well as IL-1β production by peritoneal macrophages in a model of LPS-induced sepsis. Additionally, RORγ inverse agonists reduced mortality in an LPS/d-galactosamine-induced fulminant hepatitis mouse model. These results illustrate a major role for RORγ in regulation of innate immunity via modulation of NLRP3 inflammasome activity. Furthermore, these data suggest that inhibiting the NLRP3 inflammasome with RORγ inverse agonists may be an effective method to treat NLRP3-associated diseases.

Inhibition of Hepatotoxicity by a LXR Inverse Agonist in a Model of Alcoholic Liver Disease

Alcohol abuse is a major cause of liver disease and mortality worldwide and is a significant public health issue. Patients with alcoholic liver disease (ALD) have severe hepatic lipid accumulation, inflammation, and fibrosis. Therapies for ALD are very limited and even abstinence from alcohol consumption does not necessarily protect patients from progression of the disease. We sought to evaluate the efficacy of a liver X receptor (LXR) inverse agonist, SR9238, in an animal model of ALD. SR9238 suppresses hepatic lipogenesis, a pathological hallmark of ALD, and we hypothesized that targeting suppression of hepatic metabolic pathways that are activated in ALD may be an effective treatment for the disease. A chronic ethanol diet with or without a final ethanol binge treatment was used to induce ALD in mice. Mice were administered the liver specific LXR inverse agonist SR9238 for 4 weeks after the mice had been maintained on the ethanol diet for 14 days. Mice developed all the hallmarks of advanced ALD demonstrating significant pathophysiology and hepatotoxicity. SR9238 significantly attenuated liver injury and hepatic steatosis and fibrosis was nearly eliminated in SR9238 treated mice. SR9238 treatment reversed the damage associated with chronic ethanol use returning the liver to near normal morphology. These results indicate that inhibiting LXR activity using the inverse agonist has a hepatoprotective effect in rodent models of ALD; thus, this pharmacological approach may be efficacious for treatment of ALD in humans.

Distinct roles for REV-ERBα and REV-ERBβ in oxidative capacity and mitochondrial biogenesis in skeletal muscle

The nuclear receptors REV-ERBα and REV-ERBβ have been demonstrated to be core members of the circadian clock and participate in the regulation of a diverse set of metabolic functions. Due to their overlapping tissue expression patterns and gene expression profiles, REV-ERBβ is thought to be redundant to REV-ERBα. Recent work has highlighted REV-ERBα's role in the regulation of skeletal muscle oxidative capacity and mitochondrial biogenesis. Considering the similarity between the REV-ERBs and the hypothesized overlap in function, we sought to determine whether REV-ERBβ-deficiency presented with a similar skeletal muscle phenotype as REV-ERBα-deficiency. Ectopic overexpression in C2C12 cells demonstrated that REV-ERBβ drives mitochondrial biogenesis and the expression of genes involved in fatty acid oxidation. Intriguingly, knock down of REV-ERBβ in C2C12 cultures also resulted in mitochondrial biogenesis and increased expression of genes involved in fatty acid β-oxidation. To determine whether these effects occurred in vivo, we examined REV-ERBβ-deficient mice and observed a similar increase in expression of genes involved in mitochondrial biogenesis and fatty acid β-oxidation. Consistent with these results, REV-ERBβ-deficient mice exhibited an altered metabolic phenotype compared to wild-type littermate controls when measured by indirect calorimetry. This likely compensated for the increased food consumption that occurred, possibly aiding in the maintenance of their weight over time. Since feeding behaviors are a direct circadian output, this study suggests that REV-ERBβ may have more subtle effects on circadian behaviors than originally identified. Furthermore, these data implicate REV-ERBβ in the control of skeletal muscle metabolism and energy expenditure and suggest that development of REV-ERBα versus REV-ERBβ selective ligands may have therapeutic utility in the treatment of metabolic syndrome.

Pharmacological targeting of the mammalian clock reveals a novel analgesic for osteoarthritis-induced pain

Environmental disruption of the circadian rhythm is linked with increased pain due to osteoarthritis (OA). We aimed to characterize the role of the clock gene in OA-induced pain more systemically using both genetic and pharmacological approaches. Genetically modified mice, (bmal1f/fNav1.8CreERT mice), generated by deleting the critical clock gene, bmal1, from Nav1.8 sensory neurons, were resistant to the development of mechanical hyperalgesia associated with OA induced by partial medial meniscectomy (PMM) of the knee. In wild-type mice, induction of OA by PMM surgery led to a substantial increase in BMAL1 expression in DRG neurons. Interestingly, pharmacological activation of the REV-ERB (a negative regulator of bmal1 transcription) with SR9009 resulted in reduction of BMAL1 expression, and a significant decrease in mechanical hyperalgesia associated with OA. Cartilage degeneration was also significantly reduced in mice treated with the REV-ERB agonist SR9009. Based on these data, we also assessed the effect of pharmacological activation of REV-ERB using a model of environmental circadian disruption with its associated mechanical hyperalgesia, and noted that SR9009 was an effective analgesic in this model as well. Our data clearly demonstrate that genetic disruption of the molecular clock, via deletion of bmal1 in the sensory neurons of the DRG, decreases pain in a model of OA. Furthermore, pharmacological activation of REV-ERB leading to suppression of BMAL1 expression may be an effective method for treating OA-related pain, as well as to reduce joint damage associated with this disease.

Adropin: An endocrine link between the biological clock and cholesterol homeostasis

Objective

Identify determinants of plasma adropin concentrations, a secreted peptide translated from the Energy Homeostasis Associated (ENHO) gene linked to metabolic control and vascular function.

Methods

Associations between plasma adropin concentrations, demographics (sex, age, BMI) and circulating biomarkers of lipid and glucose metabolism were assessed in plasma obtained after an overnight fast in humans. The regulation of adropin expression was then assessed in silico, in cultured human cells, and in animal models.

Results

In humans, plasma adropin concentrations are inversely related to atherogenic LDL-cholesterol (LDL-C) levels in men (n = 349), but not in women (n = 401). Analysis of hepatic Enho expression in male mice suggests control by the biological clock. Expression is rhythmic, peaking during maximal food consumption in the dark correlating with transcriptional activation by RORα/γ. The nadir in the light phase coincides with the rest phase and repression by Rev-erb. Plasma adropin concentrations in nonhuman primates (rhesus monkeys) also exhibit peaks coinciding with feeding times (07:00 h, 15:00 h). The ROR inverse agonists SR1001 and the 7-oxygenated sterols 7-β-hydroxysterol and 7-ketocholesterol, or the Rev-erb agonist SR9009, suppress ENHO expression in cultured human HepG2 cells. Consumption of high-cholesterol diets suppress expression of the adropin transcript in mouse liver. However, adropin over expression does not prevent hypercholesterolemia resulting from a high cholesterol diet and/or LDL receptor mutations.

Conclusions

In humans, associations between plasma adropin concentrations and LDL-C suggest a link with hepatic lipid metabolism. Mouse studies suggest that the relationship between adropin and cholesterol metabolism is unidirectional, and predominantly involves suppression of adropin expression by cholesterol and 7-oxygenated sterols. Sensing of fatty acids, cholesterol and oxysterols by the RORα/γ ligand-binding domain suggests a plausible functional link between adropin expression and cellular lipid metabolism. Furthermore, the nuclear receptors RORα/γ and Rev-erb may couple adropin synthesis with circadian rhythms in carbohydrate and lipid metabolism.

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In male humans, plasma adropin concentrations are inversely related to low-density circulating cholesterol (LDL-C) levels.

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Adropin expression is regulated by core elements of the biological clock (RORA/G, Rev-Erb).

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Sterol-sensing by the ROR ligand-binding domain provides a plausible link between adropin expression and lipid metabolism.

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In mouse liver, adropin expression is rhythmic and suppressed by exogenous (dietary) cholesterol.

Pharmacological inhibition of REV-ERB stimulates differentiation, inhibits turnover and reduces fibrosis in dystrophic muscle

Duchenne muscular dystrophy (DMD) is a debilitating X-linked disorder that is fatal. DMD patients lack the expression of the structural protein dystrophin caused by mutations within the DMD gene. The absence of functional dystrophin protein results in excessive damage from normal muscle use due to the compromised structural integrity of the dystrophin associated glycoprotein complex. As a result, DMD patients exhibit ongoing cycles of muscle destruction and regeneration that promote inflammation, fibrosis, mitochondrial dysfunction, satellite cell (SC) exhaustion and loss of skeletal and cardiac muscle function. The nuclear receptor REV-ERB suppresses myoblast differentiation and recently we have demonstrated that the REV-ERB antagonist, SR8278, stimulates muscle regeneration after acute injury. Therefore, we decided to explore whether the REV-ERB antagonist SR8278 could slow the progression of muscular dystrophy. In mdx mice SR8278 increased lean mass and muscle function, and decreased muscle fibrosis and muscle protein degradation. Interestingly, we also found that SR8278 increased the SC pool through stimulation of Notch and Wnt signaling. These results suggest that REV-ERB is a potent target for the treatment of DMD.

REV-ERBα ameliorates heart failure through transcription repression

A cure for heart failure remains a major unmet clinical need, and current therapies targeting neurohomonal and hemodynamic regulation have limited efficacy. The pathological remodeling of the myocardium has been associated with a stereotypical gene expression program, which had long been viewed as the consequence and not the driver of the disease until very recently. Despite the advance, there is no therapy available to reverse the already committed gene program. Here, we demonstrate that transcriptional repressor REV-ERB binds near driver transcription factors across the genome. Pharmacological activation of REV-ERB selectively suppresses aberrant pathologic gene expression and prevents cardiomyocyte hypertrophy. In vivo, REV-ERBα activation prevents development of cardiac hypertrophy, reduces fibrosis, and halts progression of advanced heart failure in mouse models. Thus, to our knowledge, modulation of gene networks by targeting REV-ERBα represents a novel approach to heart failure therapy.

Abstract 1620: Oral IL-10 suppresses colon carcinogenesis via elimination of pathogenic CD4+ T-cells and induction of antitumor CD8+ T-cell activity

An oral sustained-release formulation of Interleukin-10 suppressed tumor growth and enhanced survival in the APCmin/+ / Bacteroides fragilis spontaneous colon cancer model. Therapeutic benefit was associated with a 5-fold reduction in CD4+RORγt+Foxp3-IL-17+ T-helper cell, CD4+RORγt+Foxp3+IL-17+ pathogenic T-regulatory cell (pgTreg) and CD4+RORγt-Foxp3+IL-17- conventional T-regulatory cell (cTreg) numbers; and a concurrent enhancement of CD8+ T-cell cytotoxicity in the colonic lamina propria. Selective subset depletion and functional blockade studies demonstrated that CD4+RORγt+IL-17+ T-cell subsets and CD4+Foxp3+ cTreg supported tumorigenesis/tumor progression whereas CD8+ cytotoxic T-lymphocytes suppressed tumor growth. These findings establish the utility of oral particulate IL-10 as a potential new therapeutic in the management of colon cancer and shed light on the cellular mechanisms that underlie its antitumor activity.

Note: This abstract was not presented at the meeting.

Citation Format: TAO GU, Magdia DeJesus, Thomas P. Burris, Nejat K. Egilmez. Oral IL-10 suppresses colon carcinogenesis via elimination of pathogenic CD4+ T-cells and induction of antitumor CD8+ T-cell activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1620. doi:10.1158/1538-7445.AM2017-1620

Targeting Th17-IL-17 Pathway in Prevention of Micro-Invasive Prostate Cancer in a Mouse Model

BACKGROUND

Chronic inflammation has been associated with the development and progression of human cancers including prostate cancer. The exact role of the inflammatory Th17-IL-17 pathway in prostate cancer remains unknown. In this study, we aimed to determine the importance of Th17 cells and IL-17 in a Pten-null prostate cancer mouse model.

METHODS

The Pten-null mice were treated by Th17 inhibitor SR1001 or anti-mouse IL-17 monoclonal antibody from 6 weeks of age up to 12 weeks of age. For SR1001 treatment, the mice were injected intraperitoneally (i.p.) twice a day with vehicle or SR1001, which was dissolved in a dimethylsulfoxide (DMSO) solution. All mice were euthanized for necropsy at 12 weeks of age. For IL-17 antibody treatment, the mice were injected intravenously (i.v.) once every two weeks with control IgG or rat anti-mouse IL-17 monoclonal antibody, which was dissolved in PBS. The injection time points were at 6, 8, and 10 weeks old. All mice were analyzed for the prostate phenotypes at 12 weeks of age.

RESULTS

We found that either SR1001 or anti-IL-17 antibody treatment decreased the formation of micro-invasive prostate cancer in Pten-null mice. The SR1001 or anti-IL-17 antibody treated mouse prostates had reduced proliferation, increased apoptosis, and reduced angiogenesis, as well as reduced inflammatory cell infiltration. By assessing the epithelial-to-mesenchymal transition (EMT) markers, we found that SR1001 or anti-IL-17 antibody treated prostate tissues had weaker EMT phenotype compared to the control treated prostates.

CONCLUSIONS

These results demonstrated that Th17-IL-17 pathway plays a key role in prostate cancer progression in Pten-null mice. Targeting Th17-IL-17 pathway could prevent micro-invasive prostate cancer formation in mice. Prostate 77:888-899, 2017. © 2017 Wiley Periodicals, Inc.

Rev-Erb co-regulates muscle regeneration via tethered interaction with the NF-Y cistrome

Objective

The loss of skeletal muscle mass and strength are a central feature of traumatic injury and degenerative myopathies. Unfortunately, pharmacological interventions typically fail to stem the long-term decline in quality of life. Reduced Rev-Erb-mediated gene suppression in cultured C2C12 myoblasts has been shown to stimulate myoblast differentiation. Yet the mechanisms that allow Rev-Erb to pleiotropically inhibit muscle differentiation are not well understood. In this study, we sought to elucidate the role of Rev-Erb in the regulation of muscle differentiation and regeneration in vivo.

Methods

Using Rev-Erbα/β shRNAs, pharmacological ligands, and Rev-Erbα null and heterozygous mice, we probed the mechanism of Rev-Erbα/β regulation of muscle differentiation and muscle regeneration.

Results

ChIP seq analysis of Rev-Erb in differentiating myoblasts showed that Rev-Erbα did not transcriptionally regulate muscle differentiation through cognate Rev-Erb/ROR-response elements but through possible interaction with the cell fate regulator NF-Y at CCAAT-motifs. Muscle differentiation is stimulated by Rev-Erb release from CCAAT-motifs at promoter and enhancer elements of a number of myogenesis proteins. Partial loss of Rev-Erb expression in mice heterozygous for Rev-Erbα accelerated muscle repair in vivo whereas Rev-Erb knockout mice showed deficiencies in regenerative repair compared to wild type mice. These phenotypic differences between heterozygous and knockout mice were not apparently dependent on MRF induction in response to injury. Similarly, pharmacological disruption of Rev-Erb suppressive activity in injured muscle accelerated regenerative repair in response to acute injury.

Conclusions

Disrupting Rev-Erb activity in injured muscle accelerates regenerative muscle repair/differentiation through transcriptional de-repression of myogenic programs. Rev-Erb, therefore, may be a potent therapeutic target for a myriad of muscular disorders.

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The nuclear receptor Rev-Erb is released from myogenic gene promoter and enhancer regions during myoblast differentiation.

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Rev-Erb regulates myoblast differentiation through interaction with the cell-fate regulator NF-Y at CCAAT-motifs.

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Rev-Erb antagonists accelerate muscle regeneration following acute muscle injury by stimulating myoblast differentiation.

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Human muscle differentiation can be regulated using pharmacological ligands that target Rev-Erb.

Oral IL-10 suppresses colon carcinogenesis via elimination of pathogenicCD4+ T-cells and induction of antitumor CD8+ T-cell activity

An oral sustained-release formulation of Interleukin-10 suppressed tumor growth and enhanced survival in the APC^min/+/Bacteroides fragilis spontaneous colon cancer model. Therapeutic benefit was associated with a 5-fold reduction in CD4⁺RORγt⁺Foxp3^-IL-17⁺ T-helper cell, CD4⁺RORγt⁺Foxp3⁺IL-17⁺ pathogenic T-regulatory cell and CD4⁺RORγt^-Foxp3⁺IL-17^- conventional T-regulatory cell numbers and a concurrent 2-fold enhancement in CD8⁺ T-cell activity in the colon. Selective subset depletion and functional blockade studies demonstrated that at steady-state CD4⁺RORγt⁺IL-17⁺ T-cell subsets and CD4⁺Foxp3⁺ cTreg supported tumorigenesis, whereas CD8⁺ cytotoxic T-lymphocytes impeded tumor progression following IL-10 therapy. Suppression of tumor growth by CD8⁺ T-cells was associated with enhanced tumor infiltration and cytotoxic granule exocytosis. These findings establish the utility of oral IL-10 as a potential new therapeutic in the management of colon cancer and shed light on the cellular mechanisms that underlie its antitumor activity.

Disrupting the key circadian regulator CLOCK leads to age-dependent cardiovascular disease

The circadian mechanism underlies daily rhythms in cardiovascular physiology and rhythm disruption is a major risk factor for heart disease and worse outcomes. However, the role of circadian rhythms is generally clinically unappreciated. Clock is a core component of the circadian mechanism and here we examine the role of Clock as a vital determinant of cardiac physiology and pathophysiology in aging. Clock^Δ19/Δ19 mice develop age-dependent increases in heart weight, hypertrophy, dilation, impaired contractility, and reduced myogenic responsiveness. Young Clock^Δ19/Δ19 hearts express dysregulated mRNAs and miRNAs in the PTEN-AKT signal pathways important for cardiac hypertrophy. We found a rhythm in the Pten gene and PTEN protein in WT hearts; rhythmic oscillations are lost in Clock^Δ19/Δ19 hearts. Changes in PTEN are associated with reduced AKT activation and changes in downstream mediators GSK-3β, PRAS40, and S6K1. Cardiomyocyte cultures confirm that Clock regulates the AKT signalling pathways crucial for cardiac hypertrophy. In old Clock^Δ19/Δ19 mice cardiac AKT, GSK3β, S6K1 phosphorylation are increased, consistent with the development of age-dependent cardiac hypertrophy. Lastly, we show that pharmacological modulation of the circadian mechanism with the REV-ERB agonist SR9009 reduces AKT activation and heart weight in old WT mice. Furthermore, SR9009 attenuates cardiac hypertrophy in mice subjected to transverse aortic constriction (TAC), supporting that the circadian mechanism plays an important role in regulating cardiac growth. These findings demonstrate a crucial role for Clock in growth and renewal; disrupting Clock leads to age-dependent cardiomyopathy. Pharmacological targeting of the circadian mechanism provides a new opportunity for treating heart disease.