Authors: Bernhardt ML, Stein P, Carvacho I, Krapp C, Ardestani G, Mehregan A, Umbach DM, Bartolomei MS, Fissore RA, Williams CJ
Journal: Proc Natl Acad Sci U S A. 2018 Oct 15. pii: 201810422. doi: 10.1073/pnas.1810422115. [Epub ahead of print]
The success of mammalian development following fertilization depends on a series of transient increases in egg cytoplasmic Ca2+, referred to as Ca2+ oscillations. Maintenance of these oscillations requires Ca2+ influx across the plasma membrane, which is mediated in part by T-type, CaV3.2 channels. Here we show using genetic mouse models that TRPM7 channels are required to support this Ca2+ influx. Eggs lacking both TRPM7 and CaV3.2 stop oscillating prematurely, indicating that together they are responsible for the majority of Ca2+ influx immediately following fertilization. Fertilized eggs lacking both channels also frequently display delayed resumption of Ca2+ oscillations, which appears to require sperm-egg fusion. TRPM7 and CaV3.2 channels almost completely account for Ca2+ influx observed following store depletion, a process previously attributed to canonical store-operated Ca2+ entry mediated by STIM/ORAI interactions. TRPM7 serves as a membrane sensor of extracellular Mg2+ and Ca2+ concentrations and mediates the effects of these ions on Ca2+ oscillation frequency. When bred to wild-type males, female mice carrying eggs lacking TRPM7 and CaV3.2 are subfertile, and their offspring have increased variance in postnatal weight. These in vivo findings confirm previous observations linking in vitro experimental alterations in Ca2+ oscillatory patterns with developmental potential and offspring growth. The identification of TRPM7 and CaV3.2 as key mediators of Ca2+ influx following fertilization provides a mechanistic basis for the rational design of culture media that optimize developmental potential in research animals, domestic animals, and humans.
Authors: Venniro M, Zhang M, Caprioli D, Hoots JK, Golden SA, Heins C, Morales M, Epstein DH, Shaham Y
Journal: Nat Neurosci. 2018 Oct 15. doi: 10.1038/s41593-018-0246-6. [Epub ahead of print]
Addiction treatment has not been appreciably improved by neuroscientific research. One problem is that mechanistic studies using rodent models do not incorporate volitional social factors, which play a critical role in human addiction. Here, using rats, we introduce an operant model of choice between drugs and social interaction. Independent of sex, drug class, drug dose, training conditions, abstinence duration, social housing, or addiction score in Diagnostic & Statistical Manual IV-based and intermittent access models, operant social reward prevented drug self-administration. This protection was lessened by delay or punishment of the social reward but neither measure was correlated with the addiction score. Social-choice-induced abstinence also prevented incubation of methamphetamine craving. This protective effect was associated with activation of central amygdala PKCδ-expressing inhibitory neurons and inhibition of anterior insular cortex activity. These findings highlight the need for incorporating social factors into neuroscience-based addiction research and support the wider implantation of socially based addiction treatments.
Authors: Joshi AA, Lerman JB, Dey AK, Sajja AP, Belur AD, Elnabawi YA, Rodante JA, Aberra TM, Chung J, Salahuddin T, Natarajan B, Dave J, Goyal A, Groenendyk JW, Rivers JP, Baumer Y, Teague HL, Playford MP, Bluemke DA, Ahlman MA, Chen MY, Gelfand JM, Mehta NN
Journal: JAMA Cardiol. 2018 Sep 12. doi: 10.1001/jamacardio.2018.2769. [Epub ahead of print]
IMPORTANCE: Inflammation is critical to atherosclerosis. Psoriasis, a chronic inflammatory disease associated with early cardiovascular events and increased aortic vascular inflammation (VI), provides a model to study the process of early atherogenesis. Fludeoxyglucose F 18 positron emission tomography/computed tomography (18F-FDG PET/CT) helps quantify aortic VI, and coronary computed tomography angiography provides coronary artery disease (CAD) assessment through evaluation of total plaque burden (TB) and noncalcified coronary plaque burden (NCB), luminal stenosis, and high-risk plaques (HRP). To our knowledge, association between aortic VI and broad CAD indices has not yet been assessed in a chronic inflammatory disease state. Such a study may provide information regarding the utility of aortic VI in capturing early CAD.
OBJECTIVE: To assess the association between aortic VI and CAD indices, including TB, NCB, luminal stenosis, and HRP prevalence, in psoriasis.
DESIGN, SETTING, AND PARTICIPANTS: In a cross-sectional cohort study at the National Institutes of Health, 215 consecutive patients with psoriasis were recruited from surrounding outpatient dermatology practices. All patients underwent 18F-FDG PET/CT for aortic VI assessment, and 190 of 215 patients underwent coronary computed tomography angiography to characterize CAD. The study was conducted between January 1, 2013, and May 31, 2017. Data were analyzed in March 2018.
EXPOSURES: Aortic VI assessed by 18F-FDG PET/CT.
MAIN OUTCOMES AND MEASURES: Primary outcome: TB and NCB. Secondary outcomes: luminal stenosis and HRP.
RESULTS: Among 215 patients with psoriasis (mean [SD] age, 50.4 [12.6] years; 126 men [59%]), patients with increased aortic VI had increased TB (standardized β = 0.48; P < .001), and higher prevalence of luminal stenosis (OR, 3.63; 95% CI, 1.71-7.70; P = .001) and HRP (OR, 3.05; 95% CI, 1.42-6.47; P = .004). The aortic VI and TB association was primarily driven by NCB (β = 0.49; P < .001), whereas the aortic VI and HRP association was driven by low-attenuation plaque (OR, 5.63; 95% CI, 1.96-16.19; P = .001). All associations of aortic VI remained significant after adjustment for cardiovascular risk factors: aortic VI and TB (β = 0.23; P < .001), NCB (β = 0.24; P < .001), luminal stenosis (OR, 3.40; 95% CI, 1.40-8.24; P = .007), and HRP (OR, 2.72; 95% CI, 1.08-6.83; P = .03). No association was found between aortic VI and dense-calcified coronary plaque burden.
CONCLUSIONS AND RELEVANCE: Aortic VI is associated with broad CAD indices, suggesting that aortic VI may be a surrogate for early CAD. Larger prospective studies need to assess these associations longitudinally and examine treatment effects on these outcomes.
Authors: Wang M, Zhang L, Zhu W, Zhang J, Kim SH, Wang Y, Ni L, Telljohann R, Monticone RE, McGraw K, Liu L, de Cabo R, Lakatta EG
Journal: J Am Heart Assoc. 2018 Sep 18;7(18):e009112. doi: 10.1161/JAHA.118.009112.
Background: Aging exponentially increases the incidence of morbidity and mortality of quintessential cardiovascular disease mainly due to arterial proinflammatory shifts at the molecular, cellular, and tissue levels within the arterial wall. Calorie restriction (CR) in rats improves arterial function and extends both health span and life span. How CR affects the proinflammatory landscape of molecular, cellular, and tissue phenotypic shifts within the arterial wall in rats, however, remains to be elucidated.
Methods and Results: Aortae were harvested from young (6-month-old) and old (24-month-old) Fischer 344 rats, fed ad libitum and a second group maintained on a 40% CR beginning at 1 month of age. Histopathologic and morphometric analysis of the arterial wall demonstrated that CR markedly reduced age-associated intimal medial thickening, collagen deposition, and elastin fractionation/degradation within the arterial walls. Immunostaining/blotting showed that CR effectively prevented an age-associated increase in the density of platelet-derived growth factor, matrix metalloproteinase type II activity, and transforming growth factor beta 1 and its downstream signaling molecules, phospho-mothers against decapentaplegic homolog-2/3 (p-SMAD-2/3) in the arterial wall. In early passage cultured vascular smooth muscle cells isolated from AL and CR rat aortae, CR alleviated the age-associated vascular smooth muscle cell phenotypic shifts, profibrogenic signaling, and migration/proliferation in response to platelet-derived growth factor.
Conclusions: CR reduces matrix and cellular proinflammation associated with aging that occurs within the aortic wall and that are attributable to platelet-derived growth factor signaling. Thus, CR reduces the platelet-derived growth factor-associated signaling cascade, contributing to the postponement of biological aging and preservation of a more youthful aortic wall phenotype.
Authors: Klubo-Gwiezdzinska J, Lange M, Cochran E, Semple RK, Gewert C, Brown RJ, Gorden P
Journal: Diabetes Care. 2018 Sep 10. pii: dc180884. doi: 10.2337/dc18-0884. [Epub ahead of print]
OBJECTIVE: Type B insulin resistance due to autoantibodies against the insulin receptor is characterized by diabetes refractory to massive doses of insulin, severe hypercatabolism, hyperandrogenism, and a high mortality rate. We analyzed the efficacy of combined immunosuppressive therapy in the management of this extreme form of diabetes.
RESEARCH DESIGN AND METHODS: We performed a prospective cohort study including patients with confirmed insulin receptor autoantibodies, monitored for median 72 months (25th, 75th interquartile range 25, 88), and treated with rituximab, high-dose pulsed steroids, and cyclophosphamide until remission, followed by maintenance therapy with azathioprine. Remission was defined as the amelioration of the hyperglycemia and discontinuation of insulin and/or normalization of hyperandrogenemia.
RESULTS: All data are given as median (25th, 75th interquartile range). Twenty-two patients aged 42 (25, 57) years, 86.4% women, fulfilled inclusion criteria. At baseline, fasting glucose was 307 (203, 398) mg/dL, HbA1c was 11.8% (9.7, 13.6), total testosterone (women) was 126 (57, 571) ng/dL (normal 8-60), and daily insulin requirement was 1,775 (863, 2,700) units. After 5 (4, 6.3) months, 86.4% (19 of 22) of patients achieved remission, documented by discontinuation of insulin in all patients, normal fasting glucose of 80 (76, 92) mg/dL, HbA1c of 5.5% (5.2, 6), and testosterone (women) of 28 (20, 47) ng/dL. During follow-up of 72 (25, 88) months, 13.6% (3 of 22) of patients developed disease recurrence, occurring 24 (22, 36) months after initial remission, which responded to repeated therapy. None of the patients died.
CONCLUSIONS: Combined immunosuppressive therapy has changed the natural history of this disease, from 54% mortality to a curable form of diabetes and, as such, should be recommended in patients with type B insulin resistance.
Authors: Wolff BS, Raheem SA, Saligan LN
Journal: Sci Rep. 2018 Sep 24;8(1):14238. doi: 10.1038/s41598-018-32654-1.
Fatigue is a very common and costly symptom associated with various diseases and disorders. Nonetheless, understanding the pathobiology and developing of therapies for fatigue have been difficult, partly because of a lack of consensus on the measures to phenotype this behavior, both in clinical settings and in animal studies. Here, we describe a fatigue-like behavior induced in mice by abdominal irradiation and compare three different methods of measuring changes in physical activity over time: running wheels, video home cage monitoring, and telemetry. These methods collect data passively and continuously, requiring no disruption of animals' normal home cage behavior. In our experiments, all three methods reported a fatigue-like behavior, exhibited by a reduction in physical activity following abdominal irradiation. Video tracking showed the largest fatigue effect size (Cohen's D = 1.78) over four days of monitoring, and was the only method showing a significant decrease in activity during the light period. Telemetry and running wheels showed a similar effect size (D = 1.68 and 1.65, respectively), but running wheels showed different circadian patterns of physical activity. In addition, we conducted rotarod and inverted grid suspension tests, which suggested that fatigue-like behavior was not the result of gross motor abnormalities.
Authors: Lynes J, Jackson S, Sanchez V, Dominah G, Wang X, Kuek A, Hayes CP, Benzo S, Scott GC, Chittiboina P, Zaghloul KA, Park DM, Wu J, Hourigan CS, Giles AJ, Wu T, Maric D, Chen J, Quezado M, Heiss JD, Gilbert MR, Nduom EK
Journal: Neurosurgery. 2018 Sep 4. doi: 10.1093/neuros/nyy392. [Epub ahead of print]
BACKGROUND: Glioblastoma is the most common primary malignancy of the brain, with a dismal prognosis. Immunomodulation via checkpoint inhibition has provided encouraging results in non-CNS malignancies, but prediction of responders has proven to be challenging in glioblastoma patients.
OBJECTIVE: To determine the proportion of patients who have a measurable increase of interferon gamma levels in brain tumor tissue after their first dose of nivolumab, and to evaluate the safety of using brain tumor microdialysis to monitor for immune response while evaluating the safety of the combination of anti-programmed death 1 (PD-1) and anti-lymphocyte activation gene 3 (LAG-3) checkpoint inhibition.
METHODS: The study design is a single-center, nonrandomized phase 1 clinical trial. Up to 15 adult patients with recurrent glioblastoma will be enrolled with the goal of 10 patients completing the trial over an anticipated 18 mo. Patients will undergo biopsy; placement of microdialysis catheters and lumbar drains; treatment with anti-PD-1 checkpoint inhibition; comprehensive immune biomarker collection; tumor resection; and then treatment with anti-PD-1 and anti-LAG-3 checkpoint inhibition until progression.
EXPECTED OUTCOMES: We expect interferon gamma levels to increase in the brain as measured via microdialysis in treated patients. Based on published reports, microdialysis in this patient population is expected to be safe, and anti-LAG-3 and anti-PD-1 combined will likely have a similar side effect profile to other checkpoint inhibitor combinations.
DISCUSSION: The failure of recent trials of immune therapies in glioblastoma underscores the need to appropriately measure response in the treated tissue. This trial may provide insight on indicators of which patients will respond to immune therapy.
Authors: Brick K, Thibault-Sennett S, Smagulova F, Lam KG, Pu Y, Pratto F, Camerini-Otero RD, Petukhova GV
Journal: Nature. 2018 Sep 5. doi: 10.1038/s41586-018-0492-5. [Epub ahead of print]
Meiotic recombination differs between males and females; however, when and how these differences are established is unknown. Here we identify extensive sex differences at the initiation of recombination by mapping hotspots of meiotic DNA double-strand breaks in male and female mice. Contrary to past findings in humans, few hotspots are used uniquely in either sex. Instead, grossly different recombination landscapes result from up to fifteen-fold differences in hotspot usage between males and females. Indeed, most recombination occurs at sex-biased hotspots. Sex-biased hotspots seem to be partly determined by chromosome structure, and DNA methylation, which is absent in females at the onset of meiosis, has a substantial role. Sex differences are also evident later in meiosis as the rate at which meiotic breaks are repaired as crossovers differs between males and females in distal regions. The suppression of distal crossovers may help to minimize age-related aneuploidy that arises owing to cohesion loss during dictyate arrest in females.
Authors: Zhang DL, Ghosh MC, Ollivierre H, Li Y, Rouault TA
Journal: Blood. 2018 Sep 13. pii: blood-2018-04-842997. doi: 10.1182/blood-2018-04-842997. [Epub ahead of print]
Ferroportin (FPN), the only known vertebrate iron exporter, transports iron from intestinal, splenic, and hepatic cells into the blood to provide iron to other tissues and cells in vivo. Most of the circulating iron is consumed by erythroid cells to synthesize hemoglobin. Here we found that erythroid cells not only consumed large amounts of iron, but also returned significant amounts of iron to the blood. Erythroblast-specific Fpn knockout (Fpn KO) mice developed lower serum iron levels in conjunction with tissue iron overload, and increased FPN expression in spleen and liver without changing hepcidin levels. Our results also showed that Fpn KO mice, which suffer from mild hemolytic anemia, were sensitive to phenylhydrazine-induced oxidative stress, but were able to tolerate iron deficiency upon exposure to a low iron diet and phlebotomy, supporting that the anemia of Fpn KO mice resulted from erythrocytic iron overload and resulting oxidative injury rather than a RBC production defect. Moreover, we found that the mean corpuscular volume (MCV) values of gain-of-function FPN mutation patients were positively associated with serum transferrin saturations, whereas MCVs of loss-of-function FPN mutation patients were not, supporting that erythroblasts donate iron to blood through FPN in response to serum iron levels. Our results indicate that FPN of erythroid cells plays an unexpectedly essential role in maintaining systemic iron homeostasis and protecting RBCs from oxidative stress, providing insight into the pathophysiology of FPN diseases.
Authors: Vinales KL, Begaye B, Bogardus C, Walter M, Krakoff J, Piaggi P
Journal: Diabetes. 2018 Sep 26. pii: db180696. doi: 10.2337/db18-0696. [Epub ahead of print]
Fibroblast growth factor 21 (FGF21) regulates energy expenditure (EE) and influences weight change after low-protein overfeeding in rodent models. The change in EE after low-protein overfeeding diet is a predictor of weight change in humans and a feature of the "thrifty" metabolic phenotype. However, there are no studies showing an association between circulating FGF21 and EE in humans. We assessed the changes in plasma FGF21 concentrations after 24 hours of seven dietary interventions with different macronutrient content while in a whole-room indirect calorimeter in 64 healthy subjects with normal glucose regulation. Plasma FGF21 concentration consistently increased by 3-fold only after the two low-protein (3%) overfeeding diets, one high in carbohydrate (75%) and the other high in fat (46%), with larger increases in FGF21 being associated with greater increases in 24-h EE. Subjects with smaller increases in FGF21 after the low-protein high-fat diet gained more weight after six months in free-living conditions. Therefore, the individual predisposition to weight gain over time can be assessed by 24-h overfeeding a low-protein diet and measurements of plasma FGF21 concentrations. Individuals with a blunted FGF21 response to a low-protein diet have a thrifty metabolism and are at risk for future weight gain.