Authors: Yano H, Cai NS, Xu M, Verma RK, Rea W, Hoffman AF, Shi L, Javitch JA, Bonci A, Ferré S.
Journal: Nat Commun. 2018 Feb 5;9(1):486. doi: 10.1038/s41467-017-02606-w.
The two highly homologous subtypes of stimulatory G proteins Gαs (Gs) and Gαolf (Golf) display contrasting expression patterns in the brain. Golf is predominant in the striatum, while Gs is predominant in the cortex. Yet, little is known about their functional distinctions. The dopamine D1 receptor (D1R) couples to Gs/olf and is highly expressed in cortical and striatal areas, making it an important therapeutic target for neuropsychiatric disorders. Using novel drug screening methods that allow analysis of specific G-protein subtype coupling, we found that, relative to dopamine, dihydrexidine and N-propyl-apomorphine behave as full D1R agonists when coupled to Gs, but as partial D1R agonists when coupled to Golf. The Gs/Golf-dependent biased agonism by dihydrexidine was consistently observed at the levels of cellular signaling, neuronal function, and behavior. Our findings of Gs/Golf-dependent functional selectivity in D1R ligands open a new avenue for the treatment of cortex-specific or striatum-specific neuropsychiatric dysfunction.
Authors: Choi SH, Arai AL, Mou Y, Kang B, Yen CC, Hallenbeck J, Silva AC.
Journal: Stroke. 2018 Feb 13. pii: STROKEAHA.117.019664. doi: 10.1161/STROKEAHA.117.019664. [Epub ahead of print]
BACKGROUND AND PURPOSE: MAGL (monoacylglycerol lipase) is an enzyme that hydrolyzes the endocannabinoid 2-arachidonoylglycerol and regulates the production of arachidonic acid and prostaglandins-substances that mediate tissue inflammatory response. Here, we have studied the effects of the selective MAGL inhibitors JZL184 and MJN110 and their underlying molecular mechanisms on 3 different experimental models of focal cerebral ischemia.
METHODS: SHR (spontaneously hypertensive rats) and normotensive WKY (Wistar Kyoto) rats were subject to an intracortical injection of the potent vasoconstrictor endothelin-1, permanent occlusion of a distal segment of the middle cerebral artery via craniectomy, or transient occlusion of the middle cerebral artery by the intraluminal suture method. JZL184 or MJN110 was administered 60 minutes after focal cerebral ischemia. Infarct volumes, hemispheric swelling, and functional outcomes were assessed between days 1 to 28 by magnetic resonance imaging, histology, and behavioral tests.
RESULTS: Pharmacological inhibition of MAGL significantly attenuated infarct volume and hemispheric swelling. MAGL inhibition also ameliorated sensorimotor deficits, suppressed inflammatory response, and decreased the number of degenerating neurons. These beneficial effects of MAGL inhibition were not fully abrogated by selective antagonists of cannabinoid receptors, indicating that the anti-inflammatory effects are caused by inhibition of eicosanoid production rather than by activation of cannabinoid receptors.
CONCLUSIONS: Our results suggest that MAGL may contribute to the pathophysiology of focal cerebral ischemia and is thus a promising therapeutic target for the treatment of ischemic stroke.
Authors: Cobo I, Martinelli P, Flández M, Bakiri L, Zhang M, Carrillo-de-Santa-Pau E, Jia J, Sánchez-Arévalo Lobo VJ, Megías D, Felipe I, Del Pozo N, Millán I, Thommesen L, Bruland T, Olson SH, Smith J, Schoonjans K, Bamlet WR, Petersen GM, Malats N, Amundadottir LT, Wagner EF, Real FX
Journal: Nature. 2018 Feb 22;554(7693):533-537. doi: 10.1038/nature25751. Epub 2018 Feb 14.
Chronic inflammation increases the risk of developing one of several types of cancer. Inflammatory responses are currently thought to be controlled by mechanisms that rely on transcriptional networks that are distinct from those involved in cell differentiation. The orphan nuclear receptor NR5A2 participates in a wide variety of processes, including cholesterol and glucose metabolism in the liver, resolution of endoplasmic reticulum stress, intestinal glucocorticoid production, pancreatic development and acinar differentiation. In genome-wide association studies, single nucleotide polymorphisms in the vicinity of NR5A2 have previously been associated with the risk of pancreatic adenocarcinoma. In mice, Nr5a2 heterozygosity sensitizes the pancreas to damage, impairs regeneration and cooperates with mutant Kras in tumour progression. Here, using a global transcriptomic analysis, we describe an epithelial-cell-autonomous basal pre-inflammatory state in the pancreas of Nr5a2+/- mice that is reminiscent of the early stages of pancreatitis-induced inflammation and is conserved in histologically normal human pancreases with reduced expression of NR5A2 mRNA. In Nr5a2+/- mice, NR5A2 undergoes a marked transcriptional switch, relocating from differentiation-specific to inflammatory genes and thereby promoting gene transcription that is dependent on the AP-1 transcription factor. Pancreatic deletion of Jun rescues the pre-inflammatory phenotype, as well as binding of NR5A2 to inflammatory gene promoters and the defective regenerative response to damage. These findings support the notion that, in the pancreas, the transcriptional networks involved in differentiation-specific functions also suppress inflammatory programmes. Under conditions of genetic or environmental constraint, these networks can be subverted to foster inflammation.
Authors: Qin Y, Roberts JD, Grimm SA, Lih FB, Deterding LJ, Li R, Chrysovergis K, Wade PA
Journal: Genome Biol. 2018 Jan 23;19(1):7. doi: 10.1186/s13059-018-1389-1.
BACKGROUND: The gut microbiome, a key constituent of the colonic environment, has been implicated as an important modulator of human health. The eukaryotic epigenome is postulated to respond to environmental stimuli through alterations in chromatin features and, ultimately, gene expression. How the host mediates epigenomic responses to gut microbiota is an emerging area of interest. Here, we profile the gutmicrobiome and chromatin characteristics in colon epithelium from mice fed either an obesogenic or control diet, followed by an analysis of the resultant changes in gene expression.
RESULTS: The obesogenic diet shapes the microbiome prior to the development of obesity, leading to altered bacterial metabolite production which predisposes the host to obesity. This microbiota-diet interaction leads to changes in histone modification at active enhancers that are enriched for binding sites for signal responsive transcription factors. These alterations of histone methylation and acetylation are associated with signaling pathways integral to the development of colon cancer. The transplantation of obesogenic diet-conditioned microbiota into germ free mice, combined with an obesogenic diet, recapitulates the features of the long-term diet regimen. The diet/microbiome-dependent changes are reflected in both the composition of the recipient animals' microbiome as well as in the set of transcription factor motifs identified at diet-influenced enhancers.
CONCLUSIONS: These findings suggest that the gut microbiome, under specific dietary exposures, stimulates a reprogramming of the enhancer landscape in the colon, with downstream effects on transcription factors. These chromatin changes may be associated with those seen during colon cancer development.
Authors: Malachowa N, Freedman B, Sturdevant DE, Kobayashi SD, Nair V, Feldmann F, Starr T, Steele-Mortimer O, Kash JC, Taubenberger JK, Feldmann H, DeLeo FR
Journal: mSphere. 2018 Jan 3;3(1). pii: e00567-17. doi: 10.1128/mSphereDirect.00567-17. eCollection 2018 Jan-Feb
Neutrophils are essential cells of host innate immunity. Although the role of neutrophils in defense against bacterial and fungal infections is well characterized, there is a relative paucity of information about their role against viral infections. Influenza A virus (IAV) infection can be associated with secondary bacterial coinfection, and it has long been posited that the ability of IAV to alter normal neutrophil functionpredisposes individuals to secondary bacterial infections. To better understand this phenomenon, we evaluated the interaction of pandemic or seasonal H1N1 IAV with human neutrophils isolated from healthy persons. These viruses were ingested by human neutrophils and elicited changes in neutrophil gene expression that are consistent with an interferon-mediated immune response. The viability of neutrophils following coculture with either pandemic or seasonal H1N1 IAV was similar for up to 18 h of culture. Notably, neutrophil exposure to seasonal (but not pandemic) IAV primed these leukocytes for enhanced functions, including production of reactive oxygen species and bactericidal activity. Taken together, our results are at variance with the universal idea that IAV impairs neutrophil function directly to predispose individuals to secondary bacterial infections. Rather, we suggest that some strains of IAV prime neutrophils for enhanced bacterial clearance.
IMPORTANCE: A long-standing notion is that IAV inhibits normal neutrophil function and thereby predisposes individuals to secondary bacterial infections. Here we report that seasonal H1N1 IAV primes human neutrophils for enhanced killing of Staphylococcus aureus. Moreover, we provide a comprehensive view of the changes in neutrophil gene expression during interaction with seasonal or pandemic IAV and report how these changes relate to functions such as bactericidal activity. This study expands our knowledge of IAV interactions with human neutrophils.
Authors: Ramsuran V, Naranbhai V, Horowitz A, Qi Y, Martin MP, Yuki Y, Gao X, Walker-Sperling V, Del Prete GQ, Schneider DK, Lifson JD, Fellay J, Deeks SG, Martin JN, Goedert JJ, Wolinsky SM, Michael NL, Kirk GD, Buchbinder S, Haas D, Ndung'u T, Goulder P, Parham P, Walker BD, Carlson JM, Carrington M.
Journal: Science. 2018 Jan 5;359(6371):86-90. doi: 10.1126/science.aam8825. Epub 2018 Jan 4.
The highly polymorphic human leukocyte antigen (HLA) locus encodes cell surface proteins that are critical for immunity. HLA-A expression levels vary in an allele-dependent manner, diversifying allele-specific effects beyond peptide-binding preference. Analysis of 9763 HIV-infected individuals from 21 cohorts shows that higher HLA-A levels confer poorer control of HIV. Elevated HLA-A expression provides enhanced levels of an HLA-A-derived signal peptide that specifically binds and determines expression levels of HLA-E, the ligand for the inhibitory NKG2A natural killer (NK) cell receptor. HLA-B haplotypes that favor NKG2A-mediated NK cell licensing (i.e., education) exacerbate the deleterious effect of high HLA-A on HIV control, consistent with NKG2A-mediated inhibition impairing NK cell clearance of HIV-infected targets. Therapeutic blockade of HLA-E:NKG2A interaction may yield benefit in HIV disease.
Authors: Sivro A, Schuetz A,, Sheward D, Joag V, Yegorov S, Liebenberg L, Yende-Zuma N, Stalker A, Mwatelah RS, Selhorst P, Garrett N, Samsunder N, Balgobin A, Nawaz F, Cicala C, Arthos J, Fauci AS, Anzala AO, Kimani J, Bagaya BS, Kiwanuka N, Williamson C, Kaul R, Passmore JS, Phanuphak N, Ananworanich J, Ansari A, Abdool Karim Q, Abdool Karim SS, McKinnon LR; CAPRISA004 and RV254 study groups
Journal: Sci Transl Med. 2018 Jan 24;10(425). pii: eaam6354. doi: 10.1126/scitranslmed.aam6354.
The gastrointestinal (GI) mucosa is central to HIV pathogenesis, and the integrin α4β7 promotes the homing of immune cells to this site, including those that serve as viral targets. Data from simian immunodeficiency virus (SIV) animal models suggest that α4β7 blockade provides prophylactic and therapeutic benefits. We show that pre-HIV infection frequencies of α4β7+ peripheral blood CD4+ T cells, independent of other T cell phenotypes and genital inflammation, were associated with increased rates of HIV acquisition in South African women. A similar acquisition effect was observed in a Kenyan cohort and in nonhuman primates (NHPs) after intravaginal SIV challenge. This association was stronger when infection was caused by HIV strains containing V2 envelope motifs with a preference for α4β7 binding. In addition, pre-HIV α4β7+ CD4+ T cells predicted a higher set-point viral load and a greater than twofold increased rate of CD4+ T cell decline. These results were confirmed in SIV-infected NHPs. Increased frequencies of pre-HIV α4β7+ CD4+ T cells were also associated with higher postinfection expression of lipopolysaccharide binding protein, a microbial translocation marker, suggestive of more extensive gut damage. CD4+ T cells expressing α4β7 were rapidly depleted very early in HIV infection, particularly from the GI mucosa, and were not restored by early antiretroviral therapy. This study provides a link between α4β7 expression and HIV clinical outcomes in humans, in line with observations made in NHPs. Given the availability of a clinically approved anti-α4β7 monoclonal antibody for treatment of inflammatory bowel disease, these data support further evaluation of targeting α4β7 integrin as a clinical intervention during HIV infection.
Authors: Michels KA, Pfeiffer RM, Brinton LA, Trabert B
Journal: JAMA Oncol. 2018 Jan 18. doi: 10.1001/jamaoncol.2017.4942. [Epub ahead of print]
IMPORTANCE: Although oral contraceptive (OC) use is common, the influence of OC use on carcinogenesis is not fully understood. A recent Agency for Healthcare Research and Quality report identified a need to understand the consistency of OC use and cancer associationsacross subpopulations, including smokers and obese women.
OBJECTIVE: To determine whether associations between duration of OC use and risk of specific cancers were modified by lifestyle characteristics.
DESIGN, SETTING, AND PARTICIPANTS: The prospective NIH-AARP Diet and Health Study (enrolled 1995-1996, followed until 2011), with population-based recruitment of AARP members in 6 states and 2 metropolitan areas. All analyses included at least 100 000 women who reported OC use at enrollment. We identified 1241 ovarian, 2337 endometrial, 11 114 breast, and 3507 colorectal cancer cases during follow-up. Data analysis was performed between September 2016 and April 2017.
EXPOSURES: Duration of OC use (never or <1 year [reference], 1-4, 5-9, or ≥10 years).
MAIN OUTCOMES AND MEASURES: Development of ovarian, endometrial, breast, and colorectal cancers. We examined effect modificationby modifiable lifestyle characteristics: cigarette smoking, alcohol consumption, body mass index (BMI), and physical activity. We used Cox models adjusted for age, race, age at menarche, and the modifiers of interest.
RESULTS: The analytic population was aged 50 to 71 years (median, 62 years) at enrollment and largely white (91%) and postmenopausal (96%). For ovarian cancer, OC use-associated risk reductions strengthened with duration of use (long-term OC use [≥10 years] HR, 0.60; 95% CI, 0.47-0.76; P < .001 for trend) and were similar across modifiable lifestyle factors. Risk reductions for endometrial cancer strengthened with duration of use (long-term OC use HR, 0.66; 95% CI, 0.56-0.78; P < .001 for trend); the most pronounced reductions were among long-term OC users who were smokers (HR, 0.47; 95% CI, 0.25-0.88), had obese BMIs (0.36; 95% CI, 0.25-0.52), and who exercised rarely (HR, 0.40; 95% CI, 0.29-0.56). Associations between OC use and breast and colorectal cancers were predominantly null.
CONCLUSIONS AND RELEVANCE: Long-term OC use is consistently associated with reduced ovarian cancer risk across lifestyle factors. We observed the greatest risk reductions for endometrial cancer among women at risk for chronic diseases (ie, smokers, obese BMI). Oralcontraceptive use may be beneficial for chemoprevention for a range of women with differing baseline cancer risks.
Authors: Cheung LC, Katki HA, Chaturvedi AK, Jemal A, Berg CD
Journal: Ann Intern Med. 2018 Jan 2. doi: 10.7326/M17-2067. [Epub ahead of print]
BACKGROUND: The U.S. Preventive Services Task Force (USPSTF) recommends annual low-dose computed tomography (CT) lung cancer screening for persons aged 55 to 80 years who currently smoke or quit within the past 15 years and have at least a 30–pack-year history of cigarette smoking. The number of U.S. persons meeting USPSTF criteria for CT screening sharply decreased between 2010 and 2015. However, these criteria may exclude smokers at high risk for lung cancer who would have been selected for CT screening by individual risk calculators that more specifically account for demographic, clinical, and smoking characteristics.
OBJECTIVE: To compare USPSTF eligibility criteria with individualized, risk-based eligibility and estimate the effect of eligibility on lung cancer deaths preventable by screening since 2005.
Authors: Lee JM, Nair J, Zimmer A, Lipkowitz S, Annunziata CM, Merino MJ, Swisher EM, Harrell MI, Trepel JB, Lee MJ, Bagheri MH, Botesteanu DA, Steinberg SM, Minasian L, Ekwede I, Kohn EC
Journal: Lancet Oncol. 2018 Jan 17. pii: S1470-2045(18)30009-3. doi: 10.1016/S1470-2045(18)30009-3. [Epub ahead of print]
BACKGROUND: High-grade serous ovarian carcinoma is characterised by TP53 mutations, DNA repair defects, and genomic instability. We hypothesised that prexasertib (LY2606368), a cell cycle checkpoint kinase 1 and 2 inhibitor, would be active in BRCA wild-type disease.
METHODS: In an open-label, single-centre, two-stage, proof-of-concept phase 2 study, we enrolled women aged 18 years or older with measurable, recurrent high-grade serous or high-grade endometrioid ovarian carcinoma. All patients had a negative family history of hereditary breast and ovarian cancer or known BRCA wild-type status, measurable disease according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1, Eastern Cooperative Oncology Group performance status score 0-2, and adequate haematological, renal, hepatic, and bone-marrow function. Patients received intravenous prexasertib 105 mg/m2 administered over 1 h every 14 days in 28-day cycles until disease progression, unacceptable toxicity, or withdrawal of consent. The primary endpoint of investigator-assessed tumour response, based on RECIST version 1.1, was assessed per protocol (assessable patients who had undergone CT imaging at baseline and attended at least one protocol-specified follow-up) and by intention to treat. The final analysis of this cohort of patients with BRCA wild-type high-grade serous ovarian carcinoma is reported here. This ongoing trial is registered with ClinicalTrials.gov, number NCT02203513, and continues to enrol patients for the BRCA-mutated ovarian cancer cohort.
FINDINGS: Between Jan 20, 2015, and Nov 2, 2016, we enrolled 28 women with a median age of 64 years (IQR 58·0-69·5) who had previously received a median of 5·0 (IQR 2·5-5·0) systemic therapies. Most patients (22 [79%]) had platinum-resistant or platinum-refractory disease. All women received at least one dose of prexasertib, but four (14%) of 28 patients were not assessable for RECIST response. Eight (33%, 95% CI 16-55) of 24 patients assessable per protocol had partial responses. In the intention-to-treat population, eight (29%, 95% CI 13-49) of 28 had a partial responses. The most common (in >10% patients) grade 3 or 4 treatment-emergent adverse events were neutropenia in 26 (93%) of 28 patients, reduced white blood cell count in 23 (82%), thrombocytopenia in seven (25%), and anaemia in three (11%). Grade 4 neutropenia was reported in 22 (79%) patients after the first dose of prexasertib and was transient (median duration 6 days [IQR 4-8]) and recovered without growth-factor support in all cases. The treatment-related serious adverse event of grade 3 febrile neutropenia was reported in two (7%) patients. One patient died during the study due to tumour progression.
INTERPRETATION: Prexasertib showed clinical activity and was tolerable in patients with BRCA wild-type high-grade serous ovarian carcinoma. This drug warrants further development in this setting, especially for patients with platinum-resistant or platinum-refractory disease.